KR20050056952A - PROCESS FOR PRODUCING ALUMINA COATING COMPOSED MAINLY OF α-TYPE CRYSTAL STRUCTURE, ALUMINA COATING COMPOSED MAINLY OF α-TYPE CRYSTAL STRUCTURE, LAMINATE COATING INCLUDING THE ALUMINA COATING, MEMBER CLAD WITH THE ALUMINA COATING OR LAMINATE COATING, PROCESS FOR PRODUCING THE MEMBER, AND PHYSICAL EVAPORATION APPARATUS - Google Patents

Abstract

A process for producing an alumina coating composed mainly of alpha- type crystal structure especially excelling in heat resistance, comprising (1) providing a laminate coating including a hard coating composed of a metal component containing Al and Ti as unavoidable elements and a compound of B, C, N, O, etc., oxidizing the hard coating to thereby form an oxide-containing layer, and forming an alumina coating composed mainly of alpha-type crystal structure on the oxide-containing layer. Alternatively, the process comprises (2) forming a hard coating composed of a metal whose standard free energy for oxide formation is greater than that of aluminum and a compound of B, C, N, O, etc., oxidizing the surface of the hard coating to thereby form an oxide- containing layer, and forming an alumina coating while being accompanied by reduction of the oxide at the surface of the oxide-containing layer.

Description

Method for producing alumina film of α-form crystal structure main body, Laminated film comprising alumina film of α-type crystal structure main body and the alumina film, Member coated with the alumina film or laminate film and its manufacturing method, Physical vapor deposition apparatus {PROCESS FOR PRODUCING ALUMINA COATING COMPOSED MAINLY OF α-TYPE CRYSTAL STRUCTURE, ALUMINA COATING COMPOSED MAINLY OF α-TYPE CRYSTAL STRUCTURE, LAMINATE COATING INCLUDING THE ALUMINA COATING, MEMBER CLAD WITH THE ALUMINA COATING OR LAMINATE COATING ATE PHYSICAL EVAPORATION APPARATUS}

The present invention provides a method for producing an alumina film of the α-type crystal structure main body, a laminated film comprising the alumina film of the α-type crystal structure main body and the alumina film, a member coated with the alumina film or the laminated film, and a method of producing the same. The present invention also relates to a physical vapor deposition apparatus used for their production.

Specifically, the alumina film of the α-type crystal structure main body having excellent abrasion resistance and heat resistance coated on abrasion resistant members such as a cutting tool, a sliding member, a metal mold, and the like can be used. A useful manufacturing method which can be formed at low temperature conditions that are not damaged, a laminated film comprising the obtained alumina film of the α-form crystal structure main body and an alumina film of the α-type crystal structure main body, coated with the alumina film or the laminated film thereof Forming an oxide-based hard coating such as the alumina coating having excellent abrasion resistance and heat resistance applied to a member, a method of manufacturing the same, and a wear resistant member such as a cutting tool, a sliding member, and a mold on the surface of a substrate such as a cutting tool or a sliding member To a physical vapor deposition apparatus.

In addition, the present invention is based on a cubic boron nitride (hereinafter, abbreviated as "cBN") sintered body having excellent abrasion resistance, and an alumina film mainly composed of an α-type crystal structure having excellent oxidation resistance on the substrate. It also relates to a useful method for producing a film, and a surface coating member having such a coating to have excellent abrasion resistance and oxidation resistance, and a useful method for producing such a surface coating member. The invention method ".

In addition, although the alumina film of the (alpha) -type crystal structure main body of this invention is applicable to the member of the various uses mentioned above, it demonstrates centering on the case where it applies to a cutting tool as a representative example below.

In general, as a cutting tool or a sliding member requiring excellent wear resistance and sliding characteristics, a hard film such as titanium nitride or titanium aluminum nitride is coated on the surface of a substrate made of high speed steel or cemented carbide, or physical vapor deposition (hereinafter referred to as PVD method). What is formed by methods, such as a chemical vapor deposition method (henceforth CVD method), is used.

Particularly, when used as a cutting tool, since the hard film is required to have abrasion resistance and heat resistance (oxidation resistance at high temperature) as characteristics, it has both characteristics. Especially, titanium aluminum nitride (TiAlN) has a high cutting edge temperature when cutting Recently, it has been used a lot as a coating material for cemented carbide tools. The reason why TiAlN exhibits excellent characteristics is that heat resistance can be improved by the action of aluminum contained in the film, and stable wear resistance and heat resistance can be maintained up to a high temperature of about 800 ° C. As TiAlN, various ones having different composition ratios of Ti and Al are used, but most of them have an atomic ratio of 50:50 to 25:75 with Ti and Al having the above characteristics.

By the way, cutting edges, such as a cutting tool, may become high temperature 1000 degreeC or more at the time of cutting. Under such a situation, since the TiAlN film alone cannot secure sufficient heat resistance, for example, as disclosed in Japanese Patent Laid-Open No. 2742049, an alumina layer is further formed on the TiAlN film to ensure heat resistance. have.

Alumina has various crystal structures depending on the temperature, but all are in a semi-stable state thermally. However, when the temperature of the blade edge at the time of cutting, such as a cutting tool, fluctuates significantly over a wide range from room temperature to 1000 ° C or more, problems such as a change in the crystal structure of alumina and cracking or peeling of the film are caused. Causes By the way, only the alumina of the α-type crystal structure (corundum structure) formed by employing the CVD method and raising the substrate temperature to 1000 ° C or higher, once formed, maintains a thermally stable structure regardless of the subsequent temperature. . Therefore, in order to give heat resistance to a cutting tool etc., it is an effective means to coat the alumina film of alpha type crystal structure.

However, in order to form an alumina having an α-type crystal structure as described above, the substrate must be heated up to 1000 ° C. or higher, so that the substrate to which it can be applied is limited. This is because, depending on the type of the substrate, it may be softened when exposed to a high temperature of 100 ° C. or higher, and the aptitude as the substrate for the wear resistant member may be lost. Moreover, even if it is a high temperature base material like a cemented carbide, when exposed to such high temperature, a problem, such as a deformation | transformation, will arise. In addition, the practical temperature range of a hard film such as a TiAlN film formed on a substrate as a film exhibiting abrasion resistance is generally about 800 ° C. at most, and when exposed to a high temperature of 100 ° C. or higher, there is a possibility that the film deteriorates and wear resistance deteriorates.

For this problem, Japanese Patent Laid-Open No. 5-208326 discloses that (Al, Cr) ₂ O ₃ mixed crystals having a high hardness of the same level as the alumina were obtained in a low temperature region of 500 ° C or lower. have. However, when the workpiece is mainly composed of iron, Cr existing on the surface of the mixed crystal film is likely to cause a chemical reaction with iron in the workpiece during cutting, so that the coating is excessively consumed and the service life is increased. It causes shortening.

In addition, O. Zywitzki, G. Hoetzsch, "Surf. Coat. (N. 86-87, 1996, p. 640-647), by forming reactive sputtering using a high power (11-17 kW) pulse power supply, an alumina film having an α-type crystal structure can be formed at 750 ° C. It is reported. However, in order to obtain alumina having an α-type crystal structure by this method, the enlargement of the pulse power supply cannot be avoided.

As a technique for solving such a problem, Japanese Patent Laid-Open No. 2002-53946 discloses an oxide film having a corundum structure (α crystal structure) having a film thickness of at least 0.005 µm with a lattice constant of 4.779 GPa or 5.000 GPa. A method of forming a layer and forming an alumina film having an α-type crystal structure on its base layer is disclosed. The component of the oxide film is preferably Cr ₂ 0 ₃ , (Fe, Cr) ₂ 0 ₃ or (Al, Cr) ₂ 0 ₃ , and the component of the oxide film is (Fe, Cr) ₂ 0 ₃ When (Fe _x , Cr _(1-x) ) ₂ 0 ₃ (where x is 0≤x≤0.54) is more preferably employed, and the component of the oxide film is (Al, Cr) ₂ 0 _{In the} case of ₃ , it is disclosed that (Al _y , Cr _(1-y) ) ₂ 0 ₃ (where y is 0 ≦ y ≦ 0.90) is more preferably employed.

Further, in Japanese Laid-Open Patent Publication No. 2002-53946, after forming a composite nitride film of Al and at least one element selected from the group consisting of Ti, Cr, and V as a hard film, (Al _z , Cr _{( 1-z)} ) N (where z is O ≦ z ≦ 0.90), and the film is oxidized to further form an oxide film having a corundum structure (α-type crystal structure). It is disclosed that it is useful to form α-type alumina on the film, and according to this method, alumina having an α-type crystal structure can be formed at a low substrate temperature.

In the above method, however, in forming an alumina film having an α-type crystal structure, for example, a CrN film is formed, and the CrN film is oxidized to form Cr ₂ 0 ₃ having a corundum structure (α-type crystal structure) as an intermediate film. Since it must form separately, there is still room for improvement in increasing the formation efficiency of a laminated film. Further, the coating film containing Cr, such as Cr ₂ 0 ₃ or (CrN + Cr ₂ 0 ₃₎ is formed as an interlayer film, because it is not a material that is generic for a cutting tool, the deterioration of the cutting performance is concerned. Therefore, it can be considered that it leaves room for improvement from the viewpoint of improving cutting performance.

In view of the above, the present invention provides an alumina film mainly composed of an α-type crystal structure or a laminated film having an alumina film mainly composed of the α-type crystal structure. Is a useful method that can be efficiently formed without interposing an interlayer film at a relatively low temperature with low device load, and a lamination film excellent in wear resistance and heat resistance obtained by such a method, and also a lamination film thereof In order to realize the tool (member) coated with the alumina film of a crystal structure main body, examination was implemented.

The alumina film obtained by the above method is alumina mainly composed of an α-type crystal structure. However, when the X-ray diffraction pattern is observed in detail, a diffraction peak indicating alumina of a crystal structure other than α-type such as γ-type is observed. Has been observed. Moreover, even when the alumina film which consists only of an alpha-type crystal structure was obtained, when the surface of the film was observed with a scanning electron microscope (SEM), the space | gap between alumina crystal grains may be large and the size of the crystal grains may be nonuniform. Therefore, it is thought that a new improvement is required to obtain an alumina film excellent in wear resistance and heat resistance more reliably.

In the present invention, in view of the above, alumina coatings having finer and more uniform abrasion resistance and heat resistance while inhibiting the formation of crystal phases other than the α-type crystal structure are impaired in the characteristics of substrates such as cutting tools and sliding members. Examination was conducted to provide a useful method for forming under low temperature conditions.

Further, in the conventional method, a crystalline α alumina can be formed at a relatively low substrate temperature, but a nitride film capable of forming a corundum structure oxide having a specific lattice constant when the film is subjected to oxidation treatment as an intermediate layer. In addition to the disadvantage of needing to be limited to this, since the intermediate layer is a stable nitride represented by CrN, there is a disadvantage that the oxidation process requires a high temperature or a prolonged oxidation treatment. Therefore, in order to perform an oxidation process in a shorter time, a new examination is needed.

In view of the above, the α element crystal structure mainly capable of performing an oxidation step at a relatively low temperature without being limited to the metal element forming the oxide having a specific lattice constant structure is mainly composed of the metal element constituting the intermediate layer. In order to provide a useful method for producing an alumina coating, a member coated with the alumina coating, and a method useful for producing the alumina coating member, a study was conducted.

Moreover, the useful method which can form the alumina film of the alpha type crystal structure main body excellent in abrasion resistance and heat resistance on a various kind of base material, without forming a specific intermediate | middle layer, the member coated with the alumina film, and its manufacture The study was also conducted for the purpose of providing a method.

In the present invention, as described above, in addition to the method of forming α-alumina on a TiAlN-based commonly used as a hard coating, or on a hard coating such as TiN or TiCN without interposing a special intermediate layer or the like, an apparatus for realizing the same. The research and development were also performed about the structure.

By the way, the cutting tool is required to have excellent abrasion resistance and heat resistance as described above, but as the material used for the cutting tool, cemented carbide, high speed steel, cBN, and the like are known, and various hard films are added to the surface of such a material (substrate). The formed material is also widely used as a cutting tool.

Among various materials mentioned above, cBN is said to be superior in strength and abrasion resistance compared to other materials. As such cBN is used, for example, a technique such as Japanese Patent Application Laid-Open No. 59-8679 (claims, etc.) This is known. In this technique, a ceramic bonded phase composed of TiC, TiN or TiCN, or Al ₂ O ₃ , WC, TiB ₂ , or the like occupies 20 to 50% by volume, with the remainder substantially consisting of cBN dispersed phases cBN Physical surface deposition method (PVD method) or chemical vapor deposition method (CVD method) is applied to the surface of the sintered body substrate, and a single layer or two or more types of Ti carbide, nitride, carbon nitride, carbonate and carbon oxide, and aluminum oxide A surface-coated cBN-based ceramic cutting tool has been proposed, which is formed by forming a hard coating layer composed of a multilayer with an average layer thickness of 5 to 20 µm, and is used for cutting of hardened hardened steel and cast iron. It is used.

Although the characteristics of the cutting tool can be determined by an appropriate combination of the tool substrate and the hard film formed on the surface thereof, the most attractive as a coating material based on the cBN sintered body in this respect is aluminum oxide (Al _2). 0 ₃ : alumina) film. It is based on a cBN sintered body having excellent plastic deformation resistance under high temperature, and an Al ₂ O ₃ film having excellent chemical stability with good adhesion, thereby providing a coating member having excellent abrasion resistance, particularly crater resistance at high temperature and high load. It is because it can be configured, and it is considered that it is suitable for application to a cutting tool etc. which such a characteristic is calculated | required.

From this point of view, various techniques for forming an alumina film on the cBN sintered base material have been proposed. For example, Japanese Patent Application Laid-Open No. 2000-44370 (the scope of claims, etc.) discloses excellent wear resistance, in particular, crater wear resistance, in order to achieve cutting of high-hardness hard materials and high-speed and high-efficiency cutting of iron-based materials. For the purpose of providing a cutting tool, a tool in which at least one Al ₂ O ₃ layer is formed on at least a part of a surface involved in cutting in a cBN sintered body substrate is proposed. The sintered substrate is 20-99% by volume of the cBN the dispersed phase, including the average particle size of less than 1.0 to 10% by volume of Al ₂ O ₃ as a combination of the following 1㎛ and alumina film is formed enough thick 0.5~50㎛ on its base will be. The Al ₂ O ₃ film had an average grain size of 0.01 to 4 μm when the thickness was 0.5 to 25 μm, and an average grain size of 0.01 to 10 μm when the thickness was 25 to 50 μm. It is also disclosed that control is effective.

On the other hand, as a technique related to a coated cBN cutting tool for metal processing, for example, Patent Publication No. 2002-543993 (claims, etc.), one or more cBN sintered body with or without sintered carbide support As a tool consisting of, the coating layer is composed of a layer of one or a plurality of heat-resistant compounds, it is disclosed that at least one of the layers is composed of particulate crystalline γ-phase alumina having a particle size of less than 0.1 µm. The alumina layer is deposited by a bipolar pulse DMS (Dual Magnetron Sputtering) technique at a substrate temperature of 450 to 700 ° C.

Alternatively, as a technique related to the same cBN cutting tool, for example, Japanese Patent Application Laid-Open No. 2002-543997 (claims, etc.) is a tool having the same configuration, but? Phase alumina as a film is formed by plasma activated chemical vapor deposition (PACVD). It is disclosed that it is deposited. In this technique, plasma is generated by applying a two-pole pulsed direct current voltage between two electrodes which are fixed and electrically connected to a tool base to be coated.

Regarding the alumina film formation, the following problems also exist in various techniques proposed so far. That is, the alumina film formed by the technique of the above-mentioned patent publication 2002-543993 (the scope of a claim, etc.) or the patent publication 2002-543997 (the scope of a claim, etc.) is an alumina ((gamma) alumina which has a (gamma) type crystal structure. However, since γ-alumina is a metastable crystalline form among aluminas in which various crystal forms exist, the γ-alumina may transform into alumina (α alumina) having an α-type crystal structure which is essentially stable when the film is exposed to a high temperature environment. In connection with this transformation, there is a possibility that a crack or a peeling of the film may occur. For this reason, it cannot fully respond to the recent cutting which tends to make high speed cutting.

In contrast, in the technique disclosed in Japanese Patent Application Laid-Open No. 2000-44370 (claims, etc.), alumina having an α-type crystal structure is also included as an alumina film to be formed. It does not occur However, in this technique, the composition of the bonding phase in the cBN sintered body which forms a film becomes limited. Moreover, although the CVD method is disclosed as a method of forming an alpha-alumina film by this technique, in this method, the substrate temperature at the time of film formation becomes a high temperature atmosphere beyond 100 degreeC, and at such high temperature, the cBN sintered compact of a base material overheats, As a result, it may transform into hBN, resulting in an undesirable situation.

In view of the above, the present inventors have prepared an alumina film which can form an alumina film mainly composed of an α-type crystal structure on a cBN sintered body base without high temperature such as CVD method and without specifying the composition of the cBN sintered body. The method, the member which coat | covered such an alumina film, and the useful method for manufacturing this alumina coating member were also examined.

1 is a thin film X-ray diffraction result of the first embodiment of the present invention (TiN film) in the second embodiment according to the first aspect.

It is a figure which shows XPS depth profiling of the film obtained by carrying out oxidation process of TiN.

3 is a thin film X-ray diffraction result of a film obtained by oxidizing TiN.

4 is a schematic explanatory diagram (top view) showing an example of a device used in the implementation of the first, second or sixth aspect.

FIG. 5 is a schematic explanatory diagram (top view) showing an example of the apparatus used for implementing the fourth aspect. FIG.

It is explanatory drawing which shows typically the method (5th aspect) of this invention.

FIG. 7 is a schematic explanatory diagram (top view) showing an example of a device used in the fifth embodiment.

8 is a schematic cross-sectional view showing an outline of a physical vapor deposition apparatus according to an embodiment of the present invention.

9 is a cross-sectional explanatory diagram showing an outline of a physical vapor deposition apparatus according to another embodiment of the present invention.

10 is a cross-sectional explanatory diagram showing an outline of a physical vapor deposition apparatus according to still another embodiment of the present invention.

11 is a thin film X-ray diffraction result of the first example of the present invention in the first example according to the first aspect.

12 is a thin film X-ray diffraction result of the first comparative example in the first example according to the first aspect.

Fig. 13 is a thin film X-ray diffraction result of Example 2 of the present invention (TiCN film) in Example 2 of the first aspect.

14 is a schematic explanatory diagram (top view) showing an example of the apparatus used in the implementation of the third aspect.

15 is a graph showing thin film X-ray diffraction results of an alumina film formed on a cBN sintered body substrate.

16 is a thin film X-ray diffraction result (film formation temperature of 750 ° C.) of an alumina film (comparative example) formed on a TiAlN film.

17 is a thin film X-ray diffraction result (film formation temperature of 750 ° C.) of an alumina film (example of the present invention) formed on a TiAlN film.

FIG. 18 is a microscopic observation photograph (a is a comparative example, b is an example of the present invention) photographing the surface of the alumina film formed on the TiAlN film by SEM. FIG.

19 is a thin film X-ray diffraction result (film formation temperature of 750 ° C.) of an alumina film (comparative example) formed on a CrN film.

20 is a thin film X-ray diffraction result (film formation temperature of 750 ° C.) of an alumina film (example of the present invention) formed on a CrN film.

Fig. 21 is a microscope observation photograph (a is a comparative example, b is an example of the present invention) photographing the surface of an alumina film formed on a CrN film.

Fig. 22 is a drawing substitute photograph showing the result of observing the crystal sphere of the alumina film obtained in the example according to the sixth aspect with a transmission electron microscope (TEM).

FIG. 23 is a drawing substitute photograph showing an enlarged portion of FIG. 22. FIG.

It is a figure which shows the thin-film X-ray-diffraction result of the alumina film on the TiAlN film obtained by the Example of this invention.

<About the first sun>

Means for obtaining a laminated film having an alumina film mainly composed of an α-type crystal structure main body having excellent abrasion resistance and heat resistance include the following means.

In the laminated film of the present invention, a laminated film having a hard film composed of a metal component consisting of Al and Ti and a compound of B, C, N, O, etc., comprising: an oxide-containing layer formed by oxidizing the hard film; It is supposed to have an alumina film mainly composed of the α-type crystal structure formed on the oxide-containing layer (hereinafter also referred to as "sun of the first ①").

It is preferable that the oxide-containing layer is most preferably made of alumina at the most surface side, and the hard coating is made of TiAlN.

In addition, a hard film composed of a metal component of Al and Ti and a compound of B, C, N, O, and the like, the group consisting of Al and Ti and Group IVa (excluding Ti), Group Va, Group VIa and Si What consists of nitrides, carbides, carbonitrides, borides, nitrates, or carbonitrides containing at least one element selected from among them as essential components may be employed, and in this case, it is particularly preferable to use one consisting of TiAlCrN.

In addition, the present invention is a laminated film having a hard film composed of a metal component containing Al and a compound of B, C, N, O and the like, wherein the most surface side formed by oxidizing the hard film is substantially composed of alumina. It may be referred to as a laminated film having a feature of having an oxide-containing layer and an alumina film mainly composed of an α-type crystal structure formed on the oxide-containing layer (hereinafter also referred to as "the first solar cell").

As a hard film which consists of a metal component which makes said Al essential, and a compound of B, C, N, O, etc., at least 1 type element chosen from the group which consists of Al, IVa group, Va group, VIa group, and Si is used. It is good to use the thing which consists of nitride, carbide, carbonitride, boride, nitrate, or carbonitride which are an essential component.

The alumina film formed on the oxide-containing layer preferably has an α-type crystal structure of 70% or more.

In this invention, the laminated | stack-coated coating tool in which such laminated film was formed in the surface is also included as a protection object.

In addition, the present invention, in addition to the laminated film having an alumina film mainly composed of the α-type crystal structure in the aspect of the first ① or the first ②, after forming the hard film, the surface of the hard film is oxidized to form an oxide-containing layer. After that, a method of producing an alumina film or a laminated film mainly composed of the α-type crystal structure, which is characterized by forming an alumina film mainly composed of the α-type crystal structure on the oxide-containing layer, is also prescribed.

The formation of the oxide-containing layer is preferably performed by maintaining the substrate temperature at 650 to 800 ° C. under an oxidizing gas-containing atmosphere, and the formation of the alumina film mainly containing the α-type crystal structure is preferably performed by PVD method. In addition, the "substrate temperature" at the time of this oxidation process shall mean the temperature of the hard-film formed on the base material, such as a cemented carbide, a carbon steel, a tool steel, etc. (it is the same below).

Formation of the oxide-containing layer and formation of the alumina film mainly composed of the α-type crystal structure are preferably performed in the same apparatus from the viewpoint of productivity improvement. More preferably, the hard film is formed and the oxide-containing layer is formed. And all of the formation of the alumina film mainly composed of the α-type crystal structure are performed in the same apparatus.

Moreover, this invention also prescribes | requires the following method, in order to obtain the laminated | multilayer film in which the alumina film of the (alpha) type crystal structure main body was formed. That is, as a method of manufacturing a laminated film in which an alumina film is formed on a hard film made of a metal compound, a compound having a standard free energy for producing oxides larger than aluminum and B, C, N, 0, or the like (for example, nitride, After forming a hard film composed of carbide, carbonitride, boride, nitrate, or carbon oxide, the surface of the hard film is oxidized to form an oxide-containing layer, followed by reduction of the oxide on the surface of the oxide-containing layer. It is a method characterized by forming an alumina film mainly composed of the α-type crystal structure (hereinafter, also referred to as "sun of the first ③").

It is preferable to use Ti as a metal whose standard free energy of oxide formation is larger than aluminum, and in this case, it is preferable to form one or two or more layers selected from the group consisting of TiN, TiC and TiCN as the hard film.

In addition, it is preferable to form a composition gradient layer of two material constituent elements to be bonded to the bonding interface between the hard film and the substrate or the hard film, because the adhesion between the substrate and the hard film or the hard film can be improved.

As such a hard film, when a hard film containing Ti as a metal component having a standard free energy of oxide generation greater than aluminum is used, a method of producing a laminated film (alumina film mainly composed of an α-type crystal structure) is provided. After oxidizing the surface of and forming a titanium oxide-containing layer, it is preferable to form an alumina film with reduction of titanium oxide on the surface of the layer, specifically forming a TiO ₂ -containing layer as the oxide-containing layer (the titanium oxide-containing layer). after, it is preferred that while in the form of alumina accompanied by reduction to the Ti ₃ O ₅ in the TiO ₂ of the layer surface for forming the alumina film.

It is preferable to form the said oxide containing layer in oxidizing gas containing atmosphere, maintaining substrate temperature at 650-800 degreeC, and it is preferable to form the alumina film which mainly has the said alpha type crystal structure by PVD method.

Also in the above method, it is preferable to perform the formation of the oxide-containing layer and the formation of an alumina film mainly composed of the α-type crystal structure in the same apparatus from the viewpoint of productivity improvement, and more preferably It is good to perform all of formation, formation of the said oxide containing layer, and formation of the alumina film which mainly has the said alpha type crystal structure in the same apparatus.

In the present invention, the laminated film produced in the aspect of the first ③, the alumina film mainly composed of the α-type crystal structure is formed on the hard film made of a metal compound, the laminated film excellent in wear resistance and heat resistance, The laminated coating tool which is excellent in abrasion resistance and heat resistance in which the laminated film was formed in the surface is also included as a protection object.

<About the second sun>

As another method of producing an alumina film mainly composed of an α-type crystal structure, a method of producing an alumina film mainly composed of an α-type crystal structure on a substrate (including a base film formed on a substrate in advance), wherein the film is formed of alumina. After forming at least any one of the following (a)-(c) films before, the manufacturing method which has a summary in the point which oxidizes the surface and forms an alumina film after that is defined (hereinafter, "the 2nd It is called the "sun of."

(a) Coatings made of pure metals or alloys

(b) coatings of metallic subjects with nitrogen, oxygen, carbon or boron

(c) coatings of metal nitrides, oxides, carbides or nitrides containing nitrogen, oxygen, carbon or boron insufficient for stoichiometric composition;

In this invention, it is preferable to perform the said oxidation process, maintaining substrate temperature at 650-800 degreeC in the oxidizing gas atmosphere in a vacuum chamber.

Moreover, the coating member in which the alumina film which mainly consists of an alpha type crystal structure was formed on the base material (including the base film previously formed on the base material), and the at least one film of said (a)-(c) is an intermediate | middle layer on the base material surface. In addition, the coating member having a summary on the point that the oxide-containing layer and the alumina film of the α-type crystal structure main body are formed in sequence on the surface side of the intermediate layer is also defined.

In manufacturing such a covering member,

(I) a step of forming at least one of the above films (a) to (c) as an intermediate layer on the substrate, a step of oxidizing the surface of the intermediate layer, followed by an alumina film mainly composed of an α-type crystal structure. Performing the forming step sequentially in the same film forming apparatus, or

(II) a step of forming a base film on the substrate, a step of forming at least one of the films (a) to (c) as an intermediate layer on the surface of the base film, and a step of oxidizing the surface of the intermediate layer. It is useful to sequentially perform a step of forming an alumina film mainly composed of an α-type crystal structure in the same film forming apparatus.

<About the third sun>

In this invention, the method of forming an alumina film of (alpha) type crystal structure main body also uses the cBN sintered compact as a base material (henceforth "the 3rd aspect"). The manufacturing method is a method of producing an alumina film mainly composed of α-type crystals on a cBN sintered body substrate composed of a bonded phase and a cubic boron nitride dispersed phase, and oxidizing the surface of the cBN sintered body substrate and then forming an alumina film. Have a point on the point.

In this method, the binder phase in the cBN sintered compact includes one or more selected from the group consisting of TiC, TiN, TiCN, AlN, TiB ₂ and Al ₂ O ₃ .

The oxidation treatment is preferably carried out under an oxidizing gas oxidizing atmosphere at a temperature of 65O to 800 DEG C, and the formation of an alumina film mainly containing the α-type crystal structure is performed at a substrate temperature of 650 to 800 DEG C. It is preferable to carry out by applying the method.

This invention also prescribes the coating member which coat | covered the alumina film which mainly consists of alpha type crystals. The coating member is a coating member coated with an alumina film mainly composed of α-type crystals on a cBN sintered body substrate composed of a bonded phase and a cubic boron nitride dispersed phase, and an oxide-containing layer is interposed between the cBN sintered body and the alumina film. It is to have a point.

In such a coating member, the bonding phase preferably comprises at least one member selected from the group consisting of TiC, TiN, TiCN, AlN, TiB _2, and Al ₂ O ₃ , and the bonding phase is 1 to 50 volumes based on the entire sintered body. It is preferable to include%.

Further, the alumina film mainly composed of the α-type crystal structure formed on the surface of the coating member has a compressive residual stress.

In manufacturing the said member, it is preferable to perform the process of oxidizing the surface of a cBN sintered compact base material, and the process of forming the alumina film which mainly has an alpha type crystal structure in the same film-forming apparatus sequentially.

<About the fourth sun>

The present invention also defines the following method as a method for producing an alumina film mainly composed of the α-type crystal structure. That is, a method of forming an alumina film mainly composed of an α-type crystal structure on a substrate (including a base film formed on the substrate in advance. The same applies to the following), wherein the surface of the substrate is subjected to a gas ion bombard treatment. The surface is oxidized and a method which has a point in the point which forms an alumina film on an oxidized surface after that (it is also called a "fourth aspect" hereafter).

As said base material, it is good to use a steel material, a cemented carbide, a cermet, a cBN sintered compact, or a ceramic sintered compact.

In the case where the base film is formed as a base material, at least one element selected from the group consisting of elements of Groups 4a, 5a and 6a, Al, Si, Fe, Cu and Y of the periodic table as the base film and It is recommended to use a compound with one or more elements in C, N, B, O, or any one or more of mutually solid solutions of these compounds.

The gas ion bombard treatment is preferably performed by applying a voltage to the substrate in a gas plasma in a vacuum chamber, and the oxidation treatment is performed by storing the substrate temperature at 650 to 800 ° C. under an oxidizing gas-containing atmosphere. It is good to do.

This invention also prescribes | regulates the manufacturing method of the member coat | covered with the alumina film of the said alpha-type crystal structure main body, The method

(1) forming a base film on a substrate;

② process of performing gas ion bombard treatment on the base film surface;

③ process of oxidizing the base film surface after gas ion bombard treatment,

(4) It is characterized in that the step of subsequently forming an alumina film mainly composed of the α-type crystal structure is carried out in the same apparatus.

As the base film, at least one member selected from the group consisting of Ti (C, N), Cr (C, N), TiAl (C, N), CrAl (C, N), and TiAlCr (C, N) is formed. It is desirable to. The Ti (C, N), Cr (C, N), TiAl (C, N), CrAl (C, N), TiAlCr (C, N) is each carbide of Ti, Cr, TiAl, CrAl, or TiAlCr , Nitride or carbon nitride (hereinafter referred to).

<About the fifth sun>

In addition, the present invention is a method for producing an alumina film mainly composed of an α-type crystal structure, and a method of forming an alumina film mainly composed of an α-type crystal structure on a substrate (including a base film previously formed on a substrate). After the metal ion bombard treatment is performed on the surface, the surface is oxidized, and a method having a summary where alumina film is formed thereafter is defined (hereinafter also referred to as "the fifth aspect").

The metal ion bombard treatment may be performed by generating a metal plasma while applying a voltage to the substrate in a vacuum chamber, and the oxidation treatment may be performed by maintaining the substrate temperature at 650 to 800 ° C. under an oxidizing gas-containing atmosphere.

It is preferable to generate a plasma of Cr or Ti from the vacuum arc evaporation source as the metal plasma.

This invention also prescribes about the member coat | covered with the alumina film of (alpha) type crystal structure main body formed in the said 5th aspect. The member is a member having an alumina film mainly composed of an α-type crystal structure on a substrate (including a base film formed on the substrate in advance), and in the vicinity of the surface of the substrate, the metal used for the metal ion bombard treatment goes to the surface layer side and has a high concentration. It is a concentration gradient layer, and is characterized in that the oxide-containing layer and the alumina film of the α-type crystal structure main body are sequentially formed on the surface side of the concentration gradient layer.

Moreover, this invention also prescribes | regulates the manufacturing method of the member coat | covered with the alumina film of the (alpha) type crystal structure principal formed in the said 5th aspect, When the method does not form a base film on a base material,

① process of performing a metal ion bombard treatment on the surface of the substrate,

② process of oxidizing substrate surface after metal ion bombard treatment,

(3) Then, the step of forming an alumina film mainly composed of the α-type crystal structure is characterized in that the steps are sequentially performed in the same apparatus.

Moreover, when forming a base film on a base material previously,

(1) forming a base film on a substrate;

② a step of performing a metal ion bombard treatment on the surface of the base coating,

③ a step of subjecting the surface of the base film after the metal ion bombard treatment to an oxidation treatment,

(4) The method is characterized in that the step of subsequently forming an alumina film mainly composed of the α-type crystal structure is carried out in the same apparatus.

The base film formed in the fifth aspect includes at least one element selected from the group consisting of elements of Groups 4a, 5a, and 6a, Al, Si, Cu, and Y, and C, N, B, and O of the periodic table. It is preferable to form any 1 or more types of the compound with 1 or more types of elements, the mutual solid solution of these compounds, or the simple substance or compound which consists of 1 or more types of elements in C, N, and B. As the base material, steel, cemented carbide, cermet, cBN sintered body, ceramic sintered body, crystalline diamond or Si wafer can be used.

<About the alumina film of this invention>

This invention also prescribes | regulates the alumina film of the alpha type crystal structure formed in the said aspect, The alumina film of the alpha type crystal structure is a physical vapor deposition method on the base material (including the base film previously formed on the base material) by the physical vapor deposition method. As the formed alumina film, when the crystal structure of the alumina film was observed with a cross-sectional transmission electron microscope (magnification: 20000 times), at least the film growth initiation portion was composed of alumina crystals having a fine structure, and in the microcrystalline region, This has the point that a crystal structure other than a type crystal structure is not observed substantially.

Here, the term "substantially" means that the present invention is not limited to 100% of the α crystal structure, but allows to include impurities that are inevitably contained in the film forming process and those containing an extremely small amount of a crystal structure. I mean.

In the alumina coating of the present invention, the (A) microstructured alumina crystal has a grain size of not more than 0.3 µm in the range from the initial stage of growth to 0.5 µm in thickness, and (B) α-type over the entire alumina coating. Crystal structures other than a crystal structure are not observed substantially, (C) the alumina of an alpha type crystal structure shows structures, such as those which grew to the columnar shape in the film surface side, and the like. Moreover, it is preferable that the film thickness of the alumina film of this invention is 0.5-20 micrometers.

<About physical vapor deposition apparatus (film deposition apparatus)>

In addition, the present invention also defines a physical vapor deposition apparatus used for the production of the alumina film or the like.

The physical vapor deposition apparatus of the present invention includes a vacuum chamber, a substrate holder (oil rotating jig) disposed in the vacuum chamber as a rotating material for storing a plurality of substrates, an inert gas and an oxidizing gas introduction mechanism into the vacuum chamber, and A plasma source disposed at a position opposite to the substrate holder (planetary rotation jig), a sputtering evaporation source disposed at a position opposite to the substrate holder (planetary rotational jig), and a position opposite to the substrate holder (planetary rotational jig) A radiant heating mechanism arranged to heat the substrate and a bias power source connected to the substrate holder (planetary rotational jig) and capable of applying a negative pulsed bias voltage to the substrate holder (planetary rotational jig) are provided. .

With such a configuration, all the processes of physical vapor deposition-related treatments such as ion bombard treatment, thermal oxidation treatment and reactive sputtering on the substrate, and film formation treatment of high heat-resistant and high wear-resistant coating, can be efficiently and stably performed. In addition, this apparatus can form an alumina film mainly composed of an α-type crystal structure at relatively low processing conditions of about 650 ° C to 800 ° C. It can increase.

In place of the plasma source or in addition to the plasma source, an arc evaporation source may be disposed at a position facing the substrate holder (the planetary rotational jig). With such a configuration, it becomes possible to perform the film forming process of the hard film by arc ion plating and the formation of the alumina film in the same apparatus. This makes it possible to diversify the type of the film that can be formed, and is effective also when forming a multilayer film.

The radiant heating mechanism may be composed of a cylindrical heating source disposed concentrically with the rotation center of the substrate holder (oily rotating jig) and a planar heating source disposed on the side of the substrate holder (oily rotating jig). do.

Moreover, by setting it as the said structure, it can be set as the compact apparatus structure which can heat a base material uniformly from inside and outside. Moreover, since the distance of a base material and a heating source can be shortened, heating efficiency can also be improved.

The cross-sectional shape of the vacuum chamber may be either rectangular, hexagonal or octagonal, and the pair of sputtering evaporation sources and the planar heating source may be arranged on inner surfaces of the vacuum chamber that face each other.

By setting it as the said structure, the physical vapor deposition apparatus which has a more compact apparatus structure can be provided. In addition, since the sputtering evaporation source and the planar superheating source can be arranged evenly, the shape of the sputtering evaporation source and the planar heating source can be made to conform to the shape of the vacuum chamber, thereby reducing the volume of the vacuum chamber. have.

The cross-sectional shape of the vacuum chamber may be hexagonal or octagonal, and a pair of the sputtering evaporation source, the planar heating source, and the arc evaporation source may be arranged on the inner side surfaces of the vacuum chamber that face each other. By setting it as the said structure, it can be set as a more compact apparatus structure.

In addition, a filament for hot electron emission may be used as the plasma source in which the longitudinal direction in the vacuum chamber and close to the substrate holder (the planetary rotating jig) is opposed to each other. By setting it as the structure, the physical vapor deposition apparatus which has a more compact apparatus structure can be provided. In addition, hot electrons emitted from the filament can be efficiently induced into the substrate.

(1) About the first sun

The present inventors conducted a study on the method for forming the alumina of the α-type crystal structure main body in the temperature range below about 800 degreeC which can maintain the characteristic of a hard film, a base material, etc. under the above-mentioned circumstances. As a result,

(1) After forming a hard film composed of a metal component containing Al as a first means and a compound of B, C, N, O, etc., the surface of the hard film is oxidized and a process of forming an oxide-containing layer is performed. A method of forming a film of, or,

(2) As a second means, after forming a hard film composed of a metal having a standard free energy of oxide formation larger than aluminum and a compound of B, C, N, O, etc., the surface of the hard film is oxidized to form an oxide containing layer, Subsequently, the method of forming an alumina film with reduction of the oxide in the oxide containing layer surface.

It was found that a good thing to adopt, and reached the present invention. Hereinafter, the first and second means will be described.

<About the first means (sun of the first ①②)>

As described above, the present inventors have referred to an alumina film (hereinafter, also simply referred to as an "α-type alumina film" or an "α-alumina film") of the α-type crystal structure principal under the above-described circumstances. As a result of research on a method for forming at a temperature range of about 800 ° C. or less capable of maintaining the properties of, as a first means, after forming a hard film containing Al such as TiAlN, TiAlCrN, etc., the surface of the film The oxide containing layer formed by oxidizing was found to be a base for forming an alumina film mainly composed of an α-type crystal structure, and the present invention was reached.

Although the detailed mechanism which can obtain such an action is not certain, when Ikeda et al. Derives from the high temperature oxidation behavior of the TiAlN film disclosed in "Thin Solid Films" [195 (1991) 99-110], the above action of the present invention is as follows. You can think of it as following reasons.

In other words, Ikeda et al. Point out that when the TiAlN film is oxidized in a high temperature oxygen-containing atmosphere, a thin alumina film is deposited on the most surface side of the TiAlN film. In addition, as a result of observation, the results of the ozone depth direction analysis of TiAlN (Ti: Al = 50: 50 at atomic ratio) oxidized by heating up to 800 ° C. in the air are shown. It is shown in 12. Fig. 12 is a film composition from the outermost surface to the inside of the film, first of all there is a layer mainly composed of alumina, an oxide layer containing Ti and Al mixed therein, and an oxide layer mainly composed of Ti It is clear that this exists.

And as is clear from the later examples performed by the present inventors, the oxidation treatment temperature (740 to 780 ° C) of the hard film made of TiAlN is relatively close to the oxidation temperature (800 ° C) in the experiment of Ikeda et al. In the present invention, it is assumed that the same layer as the above experimental results is formed.

The present inventors further oxidize the hard film containing various metal elements and perform the same measurement. As a result, when the surface of the hard film containing Al is oxidized, Al in the hard film preferentially floats on the surface and is oxidized. As a result, it was found that alumina is easy to form on the outermost surface of the formed oxide layer. When the oxide layer containing such alumina was used as the base for forming the alumina film, it was found that the alumina film of the α-type crystal structure main body was formed even in a relatively low temperature region of 800 ° C or lower. The reason why such a phenomenon occurs is that when the alumina film is formed on the oxide-containing layer formed by oxidizing the hard film, for example, by reactive sputtering, crystal nuclei of α-alumina are selectively formed on the oxide-containing layer. It is because it is formed.

<About a hard film in a first means (sun of the first ①②)>

A hard film useful for securing excellent wear resistance of cutting tools and the like, and for oxidizing the hard film to form an oxide layer useful for forming an alumina film of the α-type crystal structure main body. , A hard film made of a compound with C, N, O, or the like is employed (the first aspect 1).

As a hard film which consists of a metal component which requires Al and Ti, and a compound of B, C, N, O, etc., nitride of the metal component which requires Al and Ti, or carbide, carbonitride, boride, nitrate, carbon The hard film which consists of nitric oxide etc. can be mentioned, Specifically, TiAlN, TiAlCN, TiAlC, TiAlNO etc. can be used. Especially, the hard film which consists of TiAlN is especially preferable. In the case where the TiAlN film is used as the hard film, the composition ratio of Ti and Al can be arbitrarily set. Preferably, Ti: Al has an atomic ratio of 40:60 to 25:75.

In the present invention, Al and Ti are essential and at least one element selected from the group consisting of Group IVa (excluding Ti), Group Va, Group VIa and Si as the third element is an essential component. The coating made of nitride, carbide, carbonitride, boride, nitride oxide or carbonitride oxide may be a hard coating. Examples of the hard coating include TiAlCrN, TiAlVN, TiAlSiN, TiAlCrCN and the like. More preferably, it is preferable to use a hard film made of nitrides, carbides, carbonitrides, borides, nitrides, or carbonitrides of Al, Ti and Cr, and examples thereof include TiAlCrN, TiAlCrCN, TiAlCrON, TiAlCrBN, and the like. . In this case, it is more preferable to use the hard film which consists of TiAlCrN, and it is especially preferable to use the thing of the composition shown below.

That is, as a hard film composed of (Ti _a , Al _b , Cr _c ) (C ₁ - _d N _d ),

O.02≤a≤O.30,

O.55 ≤ b ≤ O.765,

O.06≤c,

a + b + c = 1,

0.5 ≤ d ≤ 1 (a, b, c represent the atomic ratio of Ti, Al, Cr, respectively, d represents the atomic ratio of N. is the same below), or

O.02 ≤ a ≤ O.175,

O.765≤b,

4 (b-O.75) ≤c,

a + b + c = 1

0.5 ≤ d ≤ 1 is satisfied.

Moreover, in this invention, the oxide-containing layer which consists of an alumina substantially at the outermost surface side formed by oxidizing the hard film which consists of a metal component which consists of Al, and a compound of B, C, N, O etc. on the oxide containing layer, A laminated film having an alumina film mainly composed of the α-type crystal structure to be formed is also defined (first ② mode).

At this time, at least one element selected from the group consisting of Al, group IVa, group Va, group VIa, and Si is used as a hard film composed of a metal component having Al as essential and a compound of B, C, N, O and the like. It is preferable to use nitrides, carbides, carbonitrides, borides, nitrates, or carbonitrides having as essential components. For example, AlCrN, AlCrCN, etc., in addition to containing Al and Ti as metal components as described above. Can be used.

The film thickness of the hard film is preferably 0.5 µm or more, more preferably 1 µm or more in order to sufficiently exhibit the wear resistance and the heat resistance expected of the rigid film. However, if the film thickness of the hard film is too thick, the hard film is likely to crack during cutting and the long life cannot be achieved. Therefore, the film thickness of the hard film is suppressed to 20 μm or less, more preferably 10 μm or less. Good to do.

Although the formation method of the said hard film is not specifically limited, In order to form a hard film with a high Al atomic ratio so that abrasion resistance and heat resistance may be improved, it is preferable to form by PVD method (physical vapor deposition method), As a PVD method, it is AIP (ion preform). It is more preferable to employ a rating) method or a reactive sputtering method. In addition, if the method of forming a hard film by the PVD method is adopted, film formation can be performed in the same apparatus for formation of the hard film and formation of the α-type main body alumina film described later, which is preferable from the viewpoint of productivity improvement.

<About the oxide containing layer in a 1st means (1st ②)>

In the present invention, after the hard film is formed, the surface of the hard film is oxidized to form an oxide-containing layer, and particularly, on the surface of the hard film containing Al, an oxide-containing layer substantially consisting of alumina is formed. It is preferable that the hard film be oxidized under the following conditions.

That is, it is preferable to perform the said oxidation in oxidizing gas containing atmosphere. The reason for this is that the oxide can be efficiently oxidized. For example, an atmosphere containing an oxidizing gas such as oxygen, ozone or H ₂ O ₂ can be mentioned, and of course, the atmospheric atmosphere is included.

In addition, it is preferable that the oxidation is performed by thermal oxidation while maintaining the substrate temperature at 650 to 800 ° C. If the substrate temperature is too low, oxidation is not sufficiently performed. Preferably, the substrate temperature is increased to 700 ° C or higher. Oxidation is accelerated by increasing the substrate temperature, but the upper limit of the substrate temperature needs to be suppressed to less than 100 ° C in view of the object of the present invention. In this invention, even if it is 800 degrees C or less, the oxide containing layer useful for formation of the alpha type main body alumina film mentioned later can be formed.

In the present invention, there are no particular limitations on the other conditions of the oxidation treatment, and as a specific oxidation method, in addition to the thermal oxidation, a method of irradiating an oxidizing gas such as oxygen, ozone, H ₂ O _2, or the like by plasma treatment is provided. It is also effective to adopt.

<About an alumina film of the alpha-type crystal structure main body in a 1st means (1st ②)>

As described above, based on the oxide-containing layer, an alumina film mainly composed of the α-type crystal structure can be reliably formed on the oxide-containing layer.

The α-type main body alumina film is preferably 70% or more of the α-type crystal structure because it exhibits excellent heat resistance, more preferably 90% or more of the α-type crystal structure, and most preferably 100% of the α-type crystal structure. It is

The film thickness of the α-type main body alumina coating is preferably 0.1 to 20 µm. It is because it is effective to secure 0.1 micrometer or more in order to maintain the outstanding heat resistance of this alumina film, Preferably it is 1 micrometer or more. However, if the film thickness of the α-type main body alumina film is too thick, it is not preferable because an internal stress occurs in the alumina film and cracks are likely to occur. Therefore, it is preferable that the said film thickness shall be 20 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less.

Although the formation method of (alpha) type main body alumina film is not specifically limited, Since it is necessary to carry out in high temperature area of 1000 degreeC or more in CVD method, it is not preferable, and it is preferable to employ the PVD method which can form into a film in low temperature area. Among the PVD methods, sputtering is preferable, and reactive sputtering is particularly preferable because high-speed film formation can be performed using an inexpensive metal target.

Although the board | substrate temperature at the time of this alumina film formation is not specifically prescribed, since it is easy to form (alpha) type main body alumina film, when it carries out in the temperature range of about 650-800 degreeC, it is preferable. Further, following the oxidation treatment step, if the substrate temperature during the oxidation treatment is kept constant and the α-type main body alumina coating is formed, the characteristics of the substrate and the hard coating can be maintained, and the productivity is also excellent.

In addition, in the formation of the laminated film according to the present invention, it is preferable to perform the formation of the oxide-containing layer and the formation of an alumina film mainly composed of the α-type crystal structure in the same apparatus, from the viewpoint of productivity improvement, more preferably. It is good to perform all the processes of formation of the said hard film, formation of the said oxide containing layer, and formation of the alumina film which mainly has the said alpha type crystal structure in the same apparatus.

Specifically, for example, a cemented carbide substrate is provided in a film forming apparatus (physical vapor deposition apparatus) to be described later provided with, for example, an evaporation source for AIP, a magnetron sputtering cathode, a heater heating mechanism, a substrate rotation mechanism, and the like. After employing the AIP method or the like to form a hard film such as TiAlN, the surface of the hard film is thermally oxidized in an oxidizing gas atmosphere such as oxygen, ozone, H ₂ O ₂ as described above, and then reactive sputtering. The method etc. are employ | adopted to form the alumina film of (alpha) type crystal structure main body.

The present invention also defines a laminated film coating tool on which such a laminated film is formed. As a specific application example, for example, a drawaway tip in which a base material is made of cemented carbide and TiAlN is formed as a hard film, or the base is made of cemented carbide. Cutting tools such as end mills having TiAlCrN formed as a hard coating, a draw away tip having a substrate made of cermet and formed TiAlN as a hard coating, and a die for hot working used at a high temperature. have.

<About the second means (the first ③ sun)>

As described above, the present inventors have described other means of forming an α-type main body alumina coating on a hard coating under low temperature conditions of about 800 ° C. or less, in which the standard free energy of oxide formation is oxidized to a metal larger than aluminum, that is, Al. After forming the hard film which consists of a difficult element and a compound of B, C, N, O, etc., the surface of the hard film is oxidized to form an oxide-containing layer, followed by reduction of the oxide on the surface of the oxide-containing layer. It discovered that what should just be formed an alumina film.

Although the mechanism of the said means could not be fully understood, it can be considered that it is based on the following mechanisms based on the experimental result shown below.

(a) The present inventors firstly form a TiN film as a hard film on a cemented carbide substrate, as shown in Examples relating to the first aspect described below, and then, the temperature of the substrate is maintained at about 760 ° C. in an oxygen atmosphere. After storing for 20 minutes and performing an oxidation treatment, the Al target was sputtered in argon and an oxygen atmosphere while maintaining substantially the same temperature, thereby forming an alumina film on the oxidation treatment film.

FIG. 1 mentioned later is a thin-film X-ray-diffraction result of the laminated film obtained in this way. Most of the peaks identified from FIG. 1 indicate alumina having an α-type crystal structure, and it can be seen that an alumina film mainly composed of the α-type crystal structure is formed. Moreover, the same result was obtained also when TiCN was used as a hard film.

Thus, in order to pursue the mechanism in which the alumina film mainly composed of the α-type crystal structure is formed based on the TiN film or the TiCN film, the thin film X-ray diffraction results of FIG. 1 are examined to form a base layer of the alumina film. The peaks of TiN and γ-Ti ₃ O ₅ , which are considered to be compounds, were confirmed. TiN is considered to be a compound constituting the hard coating, and γ-Ti ₃ 0 ₅ is considered to be an oxide-containing layer existing between the alumina film and the TiN film.

(b) Next, the TiN film was formed as a hard film, and depth profiling was observed by XPS about the oxidation process performed on the conditions similar to the case of FIG. The result is shown in FIG. Moreover, the thin film X-ray-diffraction result of the film after the oxidation process is shown in FIG.

2 and 3 show that Ti0 ₂ (rutile type) is formed to a depth of about 100 nm in the surface layer of the film after oxidation treatment. This result was also the same as when the TiCN coating was oxidized.

From the results of the above (a) and (b), it can be seen that TiO ₂ formed by the oxidation treatment is reduced from TiO ₂ to Ti ₃ 0 ₅ during the formation of the next alumina coating.

(c) In addition, the inventors conducted an experiment of forming an alumina film on the Cr ₂ O ₃ film, and the higher the oxygen concentration in the film formation atmosphere, the more alumina formed was likely to have an α-type crystal structure, and the oxygen concentration was high. It has already been confirmed that when a decreases, it is difficult to obtain alumina having an α-type crystal structure.

From the results of the above (a) to (c), the present inventors, in the alumina film forming step (especially its initial stage), in addition to the oxygen supplied to form the film forming atmosphere, the action of oxygen caused by the reduction of the oxide in the film This promotes crystal growth of alumina having an α-type crystal structure, in other words, when the reduction reaction of the oxide formed by the oxidation treatment of the hard film is promoted, and the oxygen concentration in the film forming atmosphere is made higher. It was found that crystal growth of alumina in the form crystal structure is promoted. Hereinafter, the conditions for realizing such a mechanism are explained in full detail.

<About a hard film in a second means (sun of the first ③)>

In the formation process of the alumina film, in order to promote the supply of oxygen on the film side, that is, the reduction of the oxide in the oxide-containing layer, the hard film is `` oxidized and becomes an oxide in the oxidation treatment step, but in the alumina film formation step, the alumina film is formed in the presence of Al. It was found that it is good to include an element which is easy to reduce an oxide "as a metal element, and for that purpose, it is very effective to employ an element whose standard free energy for oxide formation is larger than aluminum.

Examples of elements in which the standard free energy of oxide formation is larger than aluminum include Si, Cr, Fe, Mn, and the like. However, among them, the standard free energy of oxide formation of Ti is about -720 kJ / (g · mol) at around 750 ° C, which is larger than the standard free energy of oxide production of aluminum: about -900 kJ / (g · mol), Since it is easy to reduce | restore in presence of Al, it is preferable to use the hard film which consists of Ti as a metal component. In addition, it is preferable to use a hard film containing Ti as a metal component in that an alumina film having an α-type crystal structure can be formed on a hard film such as TiC or TiN which is generally used for cutting tools.

The hard coating may be formed of a metal and a compound such as B, C, N, O, or the like. For example, nitrides, carbides, carbonitrides, borides, nitrides, or carbonitrides containing the metals as essential components What consists of etc. can be formed as a hard film, Specifically, TiN, TiCN, TiC, TiCNO, TiCrN, TiSiN, etc. are mentioned.

In this invention, it is good to use TiN, TiCN, TiC among these, and, specifically, TiN, TiCN, or TiC is formed independently on a base material, and it mentions laminating two or more layers of TiN, TiCN, or TiC.

In this case, a composition gradient layer of two material constituent elements to be joined may be formed at the joining interface between the hard film and the substrate or the hard film, so as to improve the adhesion between the substrate and the hard film or the hard film.

As a specific example in the case of providing a composition inclination layer, for example, when forming a TiN film on a base material, the layer in which the N composition ratio which occupies for Ti metal film as a composition inclination layer becomes high continuously or stepwise from the base material side is formed, Forming a TiN film on the composition gradient layer is mentioned. In addition, for example, when a TiCN film is formed on a TiN film, a layer on which the C composition ratio occupies the TiN film as a composition gradient layer on the TiN film increases continuously or stepwise from the TiN film side is formed. It is mentioned to form a TiCN film on the substrate.

In the case of forming an alumina film of the α-type crystal structure main body on the hard film by using a hard film containing Ti as a metal component, first, a compound such as a nitride containing Ti as an essential element, such as TiN or TiCN, is formed. After the hard film is formed, the surface of the hard film is oxidized to form a titanium oxide-containing layer, and subsequently, in the alumina film forming step, alumina film may be formed while reducing the titanium oxide on the surface of the layer. When the surface of the film is oxidized to TiO ₂ and then the alumina film is formed while reducing Ti0 ₂ on the layer surface to Ti ₃ 0 ₅ in the formation of the alumina film, the alumina mainly composed of the α-type crystal structure is efficiently It can be seen that it can form.

The film thickness of the hard film is preferably 0.5 μm or more, more preferably 1 μm or more in order to sufficiently exhibit the wear resistance and the heat resistance expected of the hard film. However, if the film thickness of the hard film is too thick, the hard film is likely to be cracked during cutting, and the long life cannot be achieved. Therefore, the film thickness of the hard film is 20 μm or less, more preferably 10 μm or less. It is good to suppress.

Although the formation method of the said hard film is not specifically limited, It is preferable to form by PVD method, and it is more preferable to employ AIP (ion framing) method or reactive sputtering method as this PVD method. In addition, if the method of forming a hard film by the PVD method is adopted, film formation can be performed in the same apparatus for formation of the hard film and formation of the α-type main body alumina film described later, which is preferable from the viewpoint of productivity improvement.

<About formation of oxide containing layer in 2nd means (1st ③ aspect)>

In the present invention, after the hard film is formed, the surface of the hard film is oxidized, and an oxide-containing layer (in particular, in the case of using a hard film containing Ti, an oxide-containing layer substantially composed of TiO ₂ on the surface side). In order to form, it is preferable to perform oxidation of a hard film on condition of the following.

That is, it is preferable to perform the said oxidation in oxidizing gas containing atmosphere. The reason for this is that the oxide can be efficiently oxidized. For example, an atmosphere containing an oxidizing gas such as oxygen, ozone, or H ₂ O ₂ can be mentioned, and of course, the atmospheric atmosphere is included.

In addition, it is preferable that the oxidation is performed by thermal oxidation while maintaining the substrate temperature at 650 to 800 ° C. In this case, it is because oxidation is not fully performed at a low temperature below the substrate temperature of 650 ° C. Preferably, the substrate temperature is increased to 700 ° C or higher. Oxidation is accelerated by increasing the substrate temperature, but the upper limit of the substrate temperature needs to be suppressed to less than 1000 ° C in view of the object of the present invention. In this invention, even if it is 800 degrees C or less, the oxide containing layer useful for formation of the alpha type main body alumina film mentioned later can be formed.

In the present invention, there are no particular limitations on the other conditions of the oxidation treatment, and as a specific oxidation method, in addition to the thermal oxidation, a method of irradiating an oxidizing gas such as oxygen, ozone, H ₂ O _2, and the like by plasma is investigated. It is also effective to adopt.

In addition, as mentioned later, it is preferable to perform the said oxidation process in the film-forming apparatus of the alumina film formed into a film at a next process.

<About formation of the alumina film of the alpha type crystal structure main body in a 2nd means (1st ③ aspect)>

As described above, in the second means (first ③ aspect), a hard film composed of a metal having a standard free energy of oxide generation larger than aluminum and a compound such as B, C, N, O, and the like is formed. By using the oxide-containing layer obtained by oxidizing the surface as a base, an alumina film of α-type main body can be reliably formed on the oxide-containing layer. Therefore, the method for forming the α-type main body alumina film is not particularly limited, but the following method is recommended for forming the film efficiently without adversely affecting the substrate, the device, or the like.

That is, in the CVD method, since it is necessary to perform in a high temperature region of 100 ° C. or higher, it is not preferable, and it is preferable to adopt the PVD method which can form a film in the low temperature region. Among the PVD methods, sputtering is preferable, and reactive sputtering is particularly preferable because high-speed film formation can be performed using an inexpensive metal target.

Although the board | substrate temperature at the time of this alumina film formation is not specifically defined, since it is easy to form an alpha-type main body alumina film, when it carries out in the temperature range of about 650-800 degreeC, it is preferable. Further, following the oxidation treatment step, if the substrate temperature during the oxidation treatment is kept constant and the α-type main body alumina coating is formed, the characteristics of the substrate and the hard coating can be maintained, and the productivity is also excellent.

The α-type main body alumina film to be formed is preferably an α-type crystal structure of 70% or more because it exhibits excellent heat resistance, more preferably an α-type crystal structure of 90% or more, and most preferably an α-type crystal structure of 100%. %.

The film thickness of the α-type main body alumina coating is preferably 0.1 to 20 µm. It is because it is effective to secure 0.1 micrometer or more in order to maintain the outstanding heat resistance etc. of this alumina film, More preferably, it is 0.5 micrometer or more, More preferably, it is 1 micrometer or more. However, if the film thickness of the α-type main body alumina film is too thick, it is not preferable because the internal stress is generated in the alumina film and cracks are likely to occur. Therefore, it is preferable that the said film thickness shall be 20 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less.

Moreover, also when forming a laminated | multilayer film by a 2nd means (1st ③ aspect), the formation of the said oxide containing layer and formation of the alumina film mainly having the said alpha type crystal structure are the same as the case of the said 1st means. It is preferable to perform in an apparatus from a viewpoint of productivity improvement, More preferably, all the processes of the formation of the said hard film, the formation of the said oxide containing layer, and the formation of the alumina film mainly having the said alpha type crystal structure are the same apparatus. It's good to be done inside.

Specifically, for example, a substrate made of cemented carbide is provided in a film forming apparatus (physical vapor deposition apparatus) described later including, for example, an AIP evaporation source, a magnetron sputtering cathode, a heater heating mechanism, a substrate rotating mechanism, and the like. After employing the AIP method or the like to form a hard film such as TiN, the surface of the hard film is thermally oxidized in an oxidizing gas atmosphere such as oxygen, ozone, H ₂ O ₂ as described above, and then reactive sputtering. The method etc. are employ | adopted to form the alumina film of (alpha) type crystal structure main body.

The present invention is characterized in that an alumina film mainly composed of an α-type crystal structure is formed on a hard film made of a metal compound formed by the method by such a second means (first ③ aspect), characterized by excellent wear resistance and heat resistance. The laminated coating and the laminated coating coating tool on which the laminated coating is formed are also specified. Specific examples of application of the laminated coating coating tool include, for example, a drawaway tip in which a base material is made of a cemented carbide, and TiN and TiCN are formed as a hard coating; Cutting tools such as end mills made of cemented carbide and formed of TiN and TiCN as hard films, and drawaway tips made of cermet and formed of TiN and TiCN as hard films, or used at high temperatures. Processing dies; and the like.

(2) About the second sun

MEANS TO SOLVE THE PROBLEM The present inventors examined in various ways about the method which can perform the oxidation process in the said oxidation processing process in a comparatively short time, and can form the film formation mainly as (alpha) alumina. As a result, in place of the above-mentioned nitrides such as CrN, at least any one of the following (a) to (c) may be formed on the substrate as an intermediate layer, thereby completing the present invention.

(a) Coatings made of pure metals or alloys

(b) coatings of metallic subjects with nitrogen, oxygen, carbon or boron

(c) coatings of metal nitrides, oxides, carbides or borides containing insufficient nitrogen, oxygen, carbon or boron for stoichiometric composition;

According to the experiments of the present inventors, when the oxidation temperature is set to 750 ° C using a nitride such as CrN as an intermediate layer and oxidized in an oxygen gas atmosphere of 0.75 Pa, the oxidation treatment time is α at 20 minutes. Compared with the alumina formed, it became a mixed film of alpha alumina and gamma alumina in about 5 minutes. On the other hand, if an intermediate layer such as (a) to (c) is formed and the surface of the intermediate layer is oxidized, an oxide film can be sufficiently formed on the surface in about 5 minutes of treatment time, and the α type is formed on the surface. It was possible to form an alumina film mainly composed of a crystal structure.

The reason why such an effect is exerted is not all but it can be considered as follows. That is, in the case where a nitride such as CrN is formed as an intermediate layer, since CrN is a stoichiometric nitride of Cr and N firmly bonded, exposure to an oxidizing gas atmosphere for about 5 minutes does not grow enough oxide film. It is considered that the alumina grown thereon could not be mainly composed of the α-type crystal structure. On the other hand, all of the intermediate layers such as (a) to (c) are chemically unstable compared to nitrides of stoichiometric composition, and as a result, it is considered that the formation of the oxide film in the oxidation treatment process proceeds more quickly. Can be.

Below, the specific form of each intermediate | middle layer of said (a)-(c) is demonstrated.

Although the intermediate | middle layer of said (a) is a film | membrane which consists of a pure metal or an alloy, it does not specifically limit as long as an oxide can be formed with respect to the kind, From a viewpoint of forming an oxide easily, the following metal materials are preferable.

In order to easily form an alumina film in a next process, it is preferable that it is a film which forms the oxide which has a corundum structure by an oxidation process as an intermediate | middle layer, From these, Al, Cr, Fe, or these mutual alloys, or these The film which consists of an alloy which has a metal as a main component is mentioned as a preferable thing. From the viewpoint of facilitating the formation of the α-alumina film in the next step, it is also effective to select a metal having a standard free energy of oxide generation larger than aluminum, and Ti is very suitable as such a metal.

In addition, as a base material used by this invention, various things can be applied as mentioned later, The base material is the meaning including what formed the base film on the surface, However, The formation of such a base film and formation of an intermediate | middle layer are the same apparatus. In the case of using the metal film (for example, Ti if TiN is formed) for forming the base film, the structure of the film forming apparatus can be simplified.

However, in the case of using a pure metal as an intermediate layer, if the thickness is formed relatively thick, the pure metal film has a weakness of low hardness, low strength, and poor sliding characteristics. Can affect the properties of the entire coating member. In such a case, it is also useful to use the film of (b) or (c) as an intermediate layer instead of or in combination with the pure metal intermediate layer.

The film of the above (b) is mainly composed of metal, but the strength of the intermediate layer is remarkably improved by the solid solution of nitrogen or the like. However, since oxidation resistance as a film is not so high, it oxidizes easily in an oxidation process process. Nitrogen is preferable as the element to be dissolved at this time, but oxygen, carbon, boron, or a mixture thereof may be dissolved. In addition, the kind of metal used as the main body in the film of (b) can employ | adopt the same kind as the kind of pure metal in the film of said (a).

Film made of Examples of the film of the (c), for example, as Cr ₂ N, compared to the full nitride (nitride of stoichiometric composition) such as CrN low-nitrogen content compound, or, Cr ₂ N and the like a mixture of CrN, Or a film made of a compound having a low nitrogen in stoichiometry even in a CrN type crystal structure. For example, the oxidation resistance of the Cr ₂ N film is easy to oxidize because it is inferior to CrN, but the strength itself as the film is significantly improved. Although nitride is preferable as a kind of compound, oxide, carbide, boron, or these mutual solid solutions are effective. Moreover, also about the kind of metal which forms these compounds, the thing similar to the kind of pure metal in the film of said (a) can be employ | adopted.

Even if the intermediate | middle layers shown to said (a)-(c) are formed individually at some time, the effect is exhibited, but if necessary (for example, when the intensity | strength falls only by a pure metal film), those 1 type, or 2 or more types Can be formed in combination.

The film thickness of the intermediate layer (in the case of two or more layers, the total film thickness) is preferably at least 0.005 µm or more, more preferably 0.01 µm or more, and still more preferably 0.02 µm or more. When the film thickness of the intermediate layer is less than 0.005 µm, the layer thickness of the oxide-containing layer formed in the oxidation treatment process becomes too thin, making it difficult to achieve the effects of the present invention. However, if the film thickness of the intermediate layer is too thick, when applied to a cutting tool or the like, cracks are likely to occur in the intermediate layer coating, so that the lifespan can not be extended. Therefore, the film thickness of the intermediate layer is 20 µm or less, more preferably 10 µm or less. It is good to suppress.

In addition, when using a pure metal film (film of said (a)) as an intermediate | middle layer, since the film becomes comparatively low in strength, it is preferable to make the film thickness into 1 micrometer or less. In addition, when the coating member according to the present invention is used for a purpose other than a cutting tool, the relationship between the interlayer film thickness and the alumina film thickness (to be described later) is not particularly limited, but wear resistance and heat resistance are particularly required like a cutting tool. In this case, it is preferable that the thickness of the intermediate layer be less than or equal to the alumina film thickness formed thereon.

As the method for forming the intermediate layer, various PVD methods such as AIP (Arc Ion Plating) method, sputtering method and ion framing method may be applied. For example, when forming the film of said (a), it forms into a film without introducing a reactive gas especially, and when forming the film of said (b) or (c), it is suitable according to each process. What is necessary is just to introduce a reaction gas.

For example, in the case of forming the intermediate layer of the two-layer structure (lamination structure) of the (b) film and (a) film by applying the PVD method, (b) nitrogen or the like as a reactive gas when the film is formed When the film is formed while the film is introduced and the film (a) is subsequently formed thereon, the intermediate layer of the laminated structure can be formed in the same apparatus by stopping the introduction of the reactive gas. In addition, when (b) the film and (a) the film have an inclined composition, the film is formed while introducing the reactive gas in the initial stage of forming the film (b), and then the amount of the reactive gas introduced is gradually decreased. It can be set as the film of (a) (namely, a metal film), having an inclined composition.

In this invention, after forming the said intermediate | middle layer, the surface of an intermediate | middle layer is oxidized (oxidation process process) and an oxide containing layer is formed. This oxidation treatment step is preferably carried out in an apparatus (vacuum chamber) for forming an alumina film formed in the following step from the viewpoint of efficiently oxidizing, and thermal oxidation is preferably carried out by raising the substrate temperature in an atmosphere of an oxidizing gas. to be. As the oxidizing gas atmosphere at this time, for example, there may be mentioned an atmosphere containing an oxidizing gas such as oxygen, ozone, such as H ₂ O _2, among them also are included as well as an air atmosphere.

Moreover, it is preferable to perform thermal oxidation by maintaining the substrate temperature at 650 to 800 ° C. If the substrate temperature is too low, the oxidation is not sufficiently performed. Preferably, the substrate temperature is increased to 700 ° C or higher.

Oxidation is accelerated by increasing the substrate temperature, but the upper limit of the substrate temperature needs to be suppressed to less than 100 ° C in view of the object of the present invention. In this invention, even if it is 800 degrees C or less, the oxide containing layer useful for formation of the alpha type main body alumina film mentioned later can be formed.

There is no other particular limitation for the conditions of the oxidation treatment, in addition to the thermal oxidation as a specific oxidation methods, for it to adopt a method of irradiating the plasma, an oxidizing gas such as oxygen, ozone, such as H ₂ O ₂ as well as g. Valid.

When the oxide containing layer is formed as described above, a film of alumina of the α-type crystal structure main body can be reliably formed on the surface. The α crystal structure is preferably 70% or more because it exhibits excellent heat resistance. More preferably, the α crystal structure is 90% or more, and most preferably the α crystal structure is 100%.

The film thickness of the α-type main body alumina coating is preferably 0.1 to 20 µm. It is because it is effective to ensure 0.1 micrometer or more in order to maintain the outstanding heat resistance of this alumina film, Preferably it is 1 micrometer or more. However, if the film thickness of the α-type main body alumina film is too thick, it is not preferable because an internal stress is generated in the alumina film and cracks are likely to occur. Therefore, it is preferable that the said film thickness shall be 20 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less.

Although the means for forming the α-type crystal structure principal alumina film in the second aspect is not particularly limited, the CVD method requires the PVD method which can be formed at a relatively low temperature region because the CVD method needs to be performed at a high temperature of 1000 ° C or higher. It is preferable to employ. Of these PVD methods, sputtering methods, particularly reactive sputtering methods, are very suitable because high-speed film formation can be realized using an inexpensive metal target. In addition, the temperature at the time of forming an alumina film is not specifically limited, Taking the continuity from the oxidation process of the previous process into consideration, it is preferable that it is the same level as at the time of an oxidation process, and 650-800 degreeC is suitable suitably. Moreover, since it is easy to form the alumina film of (alpha) type crystal structure main body, it is preferable in it being this temperature range.

By forming an alumina film of the α-type crystal structure main body on the surface of the substrate as described above, an alumina coating member having an intermediate layer, an oxide-containing layer, and an α-alumina film on the substrate in turn can be realized, and such members are excellent in wear resistance and heat resistance. It is used as a raw material, such as a cutting tool.

Moreover, in manufacturing such a member, it is preferable to perform each formation process of the alumina film which mainly has the said intermediate | middle layer, an oxide containing layer, and an alpha type crystal structure in the same apparatus from a viewpoint of productivity improvement. In addition, when forming an intermediate | middle layer, an oxide containing layer, and (alpha) type crystal structure principal alumina film on the base film on a base material, it is preferable to perform all these formation processes of a series of laminated film in the same apparatus.

Specifically, for example, a cemented carbide substrate is provided in a film forming apparatus (see FIG. 4) provided with an evaporation source for AIP, a magnetron sputtering cathode, a heater heating mechanism, a substrate rotating mechanism, and the like. A hard film such as TiAlN, and the like, and then a film formation treatment with Cr (intermediate layer formation) is carried out, and the surface of the intermediate layer is immersed in an oxidizing gas atmosphere such as oxygen, ozone or H ₂ O ₂ as described above. The thermal oxidation is carried out, and the reactive sputtering method etc. are employ | adopted after that and the alumina film of a (alpha) type crystal structure principal is formed.

Moreover, about the base material used by this invention, hard materials, such as steel-based materials, such as high-speed steel, cemented carbides and cermets, sintered bodies containing cubic boron nitride (cBN) and ceramics, or hard crystals, such as crystalline diamond, and Si for electronic members, Various substrates can be used, including. In addition, the base film may be previously formed on the surface of such a base material separately from the intermediate layer, and may be applied to the present invention regardless of the presence or absence of the base film, the type, the single layer, and the type of the multilayer.

As a base film which may be previously formed in the surface of a base material, the metal of group 4a, 5a, 6a of a periodic table, one or more types of metal elements among Cu, Al, Si, Y, and one or more types of elements of C, N, B, 0 And one or more types of single-phase or multi-layered hard coatings selected from the compounds and mutual solid solutions. Especially, it is good to form the hard film of the single layer or multilayered structure of TiN, TiC, TiCN, TiAlN, CrN, CrAlN, and TiAlCrN on the surface of a base material. Moreover, diamond, cBN, etc. which were vapor-grown are also preferable base films.

Moreover, in order to fully exhibit the wear resistance anticipated as the said hard film, it is good to set it as 0.5 micrometer or more, More preferably, it is 1 micrometer or more. However, if the film thickness of the base film is too thick, the base film is easily cracked at the time of cutting, and the long life cannot be achieved. Therefore, the film thickness is preferably 20 μm or less, more preferably 10 μm or less. good.

As another type of base coating, so-called thermal barrier coating such as oxide ceramics (for example, Yttrium Stabilized Zirconia) may be used. In this case, there is no restriction in particular in the film thickness.

Although the formation method of the said base film is not specifically limited, In order to form the said hard film with favorable abrasion resistance, it is preferable to form by PVD method, and it is more preferable to employ AIP method or reactive sputtering method as the PVD method. In addition, if the method of forming the base film by the PVD method is adopted, film formation can be performed in the same apparatus to form the base film and the formation of the α-type main body alumina film, which is preferable from the viewpoint of productivity improvement.

(3) About the Third Sun

Next, the present inventors examine the technology which can implement | achieve the cBN sintered compact without specifying the composition of cBN sintered compact, even if it does not depend on high temperature, such as CVD, when coating the alumina film which mainly consists of alpha type crystal structure on a cBN sintered compact base material It was. As a result, after exposing the surface of the cBN sintered body in an oxidizing gas atmosphere and subjecting it to oxidation, the film is subjected to the film formation by the PVD method at a substrate temperature of 650 to 800 ° C. It discovered that a film formed and completed this invention.

According to the present invention, the alumina film of the α-type crystal structure main body having excellent oxidation resistance can be effectively formed on the cBN sintered body substrate having excellent wear resistance, thereby realizing a surface coating member having excellent wear resistance and oxidation resistance. In addition, when manufacturing the surface coating member, the composition is not exposed to the high temperature atmosphere as when the CVD method is applied, and the composition of the cBN sintered body is not restricted.

The reason why such an effect is exerted is not all that could be explained, but it can be considered as follows. The cBN sintered body contains TiC, TiN, TiCN, AlN, TiB ₂ , Al ₂ O _3, or the like as a bonding phase, and part of the cBN sintered body is also exposed to the surface layer forming the film. When this sintered compact base material is exposed to an oxidizing atmosphere at a high temperature and oxidized, the portion of the non-oxide-bonded phase in the bonded phase is exposed to the surface. In addition, even in the case of the bonding phase of an oxide such as Al ₂ O ₃ , microorganisms such as hydrocarbons are adhered to the surface microscopically, and these contaminants are removed by oxidizing and exposing to an oxidizing atmosphere at a high temperature. It can be considered that the surface of the pure oxide is exposed.

Therefore, the surface of the cBN sintered body after the oxidation treatment process is thought to be an oxide formed by oxidation of a bonding phase or a pure oxide in a bonding phase of an original oxide in a state dispersed throughout the entire surface of the substrate. do. In addition, cBN itself in the sintered body may also form an oxide on its surface.

In this way, an oxide region which becomes a region suitable for crystal growth of α-alumina is formed over the entire surface of the cBN sintered body substrate, and crystal growth of α-alumina occurs from the region as a starting point. It is conceivable that the film can be formed at a relatively low film formation temperature.

The bonding phase contained in the cBN sintered compact used as the substrate in the present invention is not limited to a specific kind, but contains at least one selected from the group consisting of TiC, TiN, TiCN, AlN, TiB ₂ and Al ₂ O ₃ . Although what is being used can be adopted, nitrides, carbides, borides of metals such as group 4a, 5a, and 6a of the periodic table or metals such as Al and Si, and their mutual solid solutions or metals (for example, Al, Ti, Cr, Fe or an alloy containing them) can also be used. In addition, in consideration of the effect of the oxidation treatment according to the present invention, it is preferable that the compound as the bonding phase contains at least a non-oxide compound.

As content of the bonding phase in a cBN sintered compact, it is preferable that it is 1-50 volume% with respect to the whole sintered compact. If the content of the bonding phase is less than 1% by volume, the desired strength cannot be secured. If the content is more than 50% by volume, the wear resistance of the substrate is lowered.

In this invention, the surface of a cBN sintered compact base material is oxidized and an oxide containing layer is formed in the surface (namely, the part used as an interface of a cBN sintered compact and an alumina film). This oxidation treatment step is preferably performed in a film forming apparatus for forming an alumina film formed in the next step from the viewpoint of efficiently producing the coating member, and thermal oxidation is preferably performed by raising the substrate temperature in an atmosphere of an oxidizing gas. It is a way. As the oxidizing gas atmosphere at this time, for example, there may be mentioned an atmosphere containing an oxidizing gas such as oxygen, ozone, H ₂ 0 _2, among them also are included as well as an air atmosphere.

Moreover, it is preferable to perform thermal oxidation by maintaining the substrate temperature at 650 to 800 ° C. If the substrate temperature is too low, the oxidation is not sufficiently performed. Preferably, the substrate temperature is increased to 700 ° C or higher. Oxidation is accelerated by increasing the substrate temperature, but the upper limit of the substrate temperature needs to be suppressed to less than 1000 ° C in view of the object of the present invention. In this invention, the oxide containing layer useful for formation of the alumina film of (alpha) type crystal structure main body can also be formed even at 800 degrees C or less.

Particular restrictions on the other conditions of the oxidation treatment is not, also to employ a method of irradiating addition to the thermal oxidation, with for example a plasma of an oxidizing gas such as oxygen, ozone, such as H ₂ O ₂ screen as specific oxidation as well as Valid.

When the oxide-containing layer as described above is formed, the alumina film of the α-type crystal structure main body can be reliably formed on the surface. The alumina film is preferably 70% or more of α-type crystal structure because it exhibits excellent heat resistance, more preferably 90% or more of α-type crystal structure, and most preferably 100% of α-crystal structure. .

It is preferable that the film thickness of the alumina film mainly containing the said alpha type crystal structure shall be 0.1-20 micrometers. In order to maintain the excellent heat resistance of the alumina film, it is effective to secure 0.1 µm or more, preferably 1 µm or more. However, if the film thickness of the α-type crystal structure main alumina film is too thick, it is not preferable because internal stress occurs in the alumina film and cracks are likely to occur. Therefore, it is preferable that the said film thickness shall be 20 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less.

The means for forming the alumina film of the α-type crystal structure main body in the third aspect is not particularly limited, but the CVD method requires the film to be performed at a high temperature of 1000 ° C. or higher, which is not preferable, and the PVD method capable of forming a film at a relatively low temperature region is preferable. It is preferable to employ. Of these PVD methods, sputtering methods, particularly reactive sputtering methods, are very suitable because high-speed film formation can be achieved using an inexpensive metal target. In addition, the temperature at the time of forming an alumina film is not specifically limited, Taking the continuity from the oxidation process of the previous process into consideration, it is preferable that it is the same level as at the time of an oxidation process process, and 650-800 degreeC is very suitable. In addition, when the alumina film is formed in this temperature range, the alumina film of the α-type crystal structure main body is likely to be formed, which is preferable.

By forming the α-type main body alumina coating on the surface of the substrate as described above, the alumina coating member, in which the substrate, the oxide-containing layer and the alumina coating of the α-type main body are formed in turn, can be realized, and such members are excellent in wear resistance and heat resistance, It is useful as a raw material such as a cutting tool.

Since the alumina film of the α-type crystal structure main body is formed by PVD method, more preferably reactive sputtering method, the residual stress of compression can be imparted by the selection of coating conditions, which is necessary to secure the strength of the whole coating member. desirable. Moreover, a trace amount of Ar other than Al and O is contained in the alumina film of the alpha type crystal structure principal formed by the reactive sputtering method.

As described above, by forming the alumina film of the α-type crystal structure main body on the surface of the cBN sintered body substrate, an alumina coating member, in which an oxide-containing layer and an α-alumina film are sequentially formed on the substrate, can be realized, and such a member is excellent in wear resistance and heat resistance. It is used as a raw material, such as a cutting tool. Moreover, in manufacture of such a member, it is preferable from a viewpoint of productivity improvement to perform each formation process of the said oxide containing layer and (alpha) alumina film in the same apparatus.

(4) About the fourth sun

MEANS TO SOLVE THE PROBLEM The present inventors made the alumina film (henceforth only an "alpha-type main body alumina film") which is fine and uniform crystal grains as an alpha type crystal structure principal, in the said base material and base film (4th aspect below, special designation) As long as there is no "substrate", the research was also conducted about the method (fourth aspect) formed in the temperature range of about 800 degrees C or less which can maintain the characteristic of the base film previously formed on the base material).

As a result, in forming the alumina film, the surface of the substrate is subjected to gas ion bombard treatment, and then the surface is oxidized, whereby the proportion of the α-type occupying the crystal structure of the alumina film is remarkably improved, and the alumina crystal grain is fine. The present invention was found to be uniform while being used. The mechanism in which the method effectively acts on the formation of the α-type main body alumina film is estimated once as follows from the experimental results in the fourth embodiment described later.

As described above, according to the conventional method, in forming the alumina film on the CrN film, the surface of the CrN film is oxidized, whereby an alumina film mainly composed of the α-type crystal structure can be formed.

As a mechanism of this method, prior to the formation of an alumina film, by exposing the surface of the CrN film to be formed into an oxidizing atmosphere, Cr ₂ 0 ₃ having the same crystal structure as that of the alumina of the α-type crystal structure is formed on the surface, and this surface state It can be considered that is very suitable for generation of alumina crystal nuclei of α-type crystal structure at the time of alumina film formation.

However, when the alumina film is formed by this method, when the surface of the film is observed by SEM, the alumina crystal grains are coarsened and interspersed as shown in Comparative Example in the fourth aspect described later. As a reason, not all regions of the oxidation treatment surface are in a state that is very suitable for the production of alumina crystal nuclei having an α-type crystal structure. Specifically, the surface state of the CrN film before the oxidation treatment is not necessarily uniform. It can be seen that the surface is also in an uneven state.

In contrast, in the case of oxidation treatment after performing gas ion bombard treatment as in the present invention, when the surface of the formed alumina film is observed by SEM, the crystal grains of alumina having an α-type crystal structure are represented as shown in Examples of the present invention described later. Is finer and more uniform than that formed by the conventional method.

From these results, it can be estimated that the gas ion bombard treatment before the oxidation treatment results in a more numerous and uniform generation point of the alumina crystal nucleus of the α-type crystal structure formed by the oxidation treatment.

The details of this mechanism are not clear, but for example you can think of: That is, in the fourth aspect, the adsorption water, the contact, and the natural oxide film existing on the surface of the coating film such as CrN are removed by the gas ion bombard treatment, and the surface is easily oxidized with oxygen, so that the film is coated. It can be considered that the oxide serving as the formation point of the alumina crystal nucleus of the α-type crystal structure is formed finely and uniformly on the surface.

Below, preferable embodiment etc. in the said 4th aspect are explained in full detail.

<About gas ion bombard processing>

In the fourth aspect, as described above, in forming the alumina film, the surface of the substrate is subjected to a gas ion bombard treatment, and then the surface is oxidized, and the specific conditions of the gas ion bombard treatment are not particularly limited. It is good to employ suitably the conditions which can etch the surface of a base material.

As a specific method, as shown in FIG. 5 mentioned later, the following method using the plasma of a filament excitation is mentioned, for example. That is, in the state in which an inert gas such as Ar is introduced into the vacuum chamber, hot electrons are generated from the filament to generate a discharge, and gas ions such as Ar in the plasma generated by the discharge are accelerated to a negative voltage applied to the substrate to collide. It is a method of etching a base material surface by making it etch.

In the application of the voltage, as described above, a negative DC voltage may be applied continuously or intermittently, or an AC voltage of high frequency may be applied.

In order to accelerate generated gas ions such as Ar toward the substrate and sufficiently etch the surface of the substrate, the negative DC voltage is preferably set to -100 V or more (preferably -300 V or more). However, if the negative voltage is too large, there is a risk of adverse effects such as generation of an arc discharge. Therefore, it is preferable to suppress the voltage to -2000V or less (preferably -10OV or less). In addition, when applying a high frequency AC voltage, it is good to make the self-bias generated about the same as the said DC voltage.

The gas ion species to be used is not particularly limited as long as it has an etching effect, and rare gases such as Ar, Kr, and Xe can be used. Especially, it is preferable to use Ar gas which is relatively inexpensive and is generally used.

The plasma may be generated by a method such as holo cathode discharge or RF (radio frequency) discharge in addition to the filament.

In addition, as a simpler method, an inert gas such as Ar is introduced into the vacuum chamber, and a glow discharge is generated by applying a negative DC voltage or a high frequency AC voltage to the substrate, thereby generating gas ions (Ar ions) in the plasma. Etc.) may be accelerated to the applied voltage.

As another specific form of the gas ion bombard treatment, a method of colliding high acceleration gas ions generated from an ion beam source to the surface of the substrate may be employed.

<About base material and base film in 4th aspect>

In the 4th aspect, in addition to using the base material which comprises members, such as a cutting tool, as a base material, in order to provide characteristics, such as abrasion resistance, the thing in which the base film of single layer or multilayer was formed previously on the base material can also be used. Although it does not prescribe the specific kind of the base material or base film, but when this invention method is applied to manufacture of a cutting tool, a sliding member, a metal mold | die etc. which require the outstanding heat resistance, abrasion resistance, etc., as the base material and base film, Is preferably used.

As a base material, steel-based materials, such as high-speed steel, a cemented carbide, a cermet, a cBN (cubic boron nitride) sintered compact, and a ceramic sintered compact can be used.

When using what formed the base film on the base material, the kind of base material does not matter in particular. Examples of the base film include at least one element selected from the group consisting of elements of Groups 4a, 5a, and 6a, Al, Si, Fe, Cu, and Y, and C, N, B, and O of the periodic table. Forming any one or more of a compound with at least one element or a mutual solid solution of these compounds is preferable because an oxide layer advantageous for forming alumina of the α-type crystal structure is formed.

Representative of the base film, Ti (C, N), Cr (C, N), TiAl (C, N), CrAl (C, N), TiAlCr (C, N), that is, Ti, Cr, TiAl, Carbides, nitrides, carbon and nitrides of CrAl or TiAlCr, and are hard films commonly used for cutting tools and the like. For example, TiN, TiC, TiCN, TiAlN, CrN, CrAlN, TiAlCrN may be formed in a single layer or a multilayer. Can be.

The film thickness of the base film is preferably 0.5 μm or more, more preferably 1 μm or more in order to sufficiently exhibit wear resistance, heat resistance, and the like that is expected of the film. However, if the film thickness of the base film is too thick, cracks are likely to occur in the film during cutting, and the life of the film cannot be extended. Therefore, the film thickness of the base film is suppressed to 20 µm or less, more preferably 10 µm or less. Good to do.

Although the formation method of the said base film is not specifically limited, It is preferable to form by PVD method, and it is more preferable to employ AIP (Ion Plating) method or reactive sputtering method as this PVD method. In addition, by adopting a method of forming a base film such as a hard film by the PVD method, it is possible to form the base film and the formation of the α-type main body alumina film described later in the same apparatus. Do.

<About the oxidation treatment method in the fourth aspect>

In a fourth aspect, the base film surface is subjected to oxidation after the gas ion bombard treatment. Although it does not specifically limit about the conditions of the said oxidation process, In order to form an oxide containing layer advantageous for production | generation of the alumina crystal nucleus of an alpha type crystal structure efficiently, it is preferable to oxidize on condition of the following.

That is, it is preferable to perform the said oxidation in oxidizing gas containing atmosphere. The reason for this is that the oxide can be efficiently oxidized. For example, an atmosphere containing oxidizing gas such as oxygen, ozone, H ₂ O ₂ or the like can be mentioned.

Moreover, it is preferable to perform thermal oxidation by maintaining the substrate temperature at 650 to 800 ° C. If the substrate temperature is too low, the oxidation is not sufficiently performed. Preferably, the substrate temperature is increased to 700 ° C or higher. Oxidation is accelerated by increasing the substrate temperature, but the upper limit of the substrate temperature needs to be suppressed to less than 1000 ° C in view of the object of the present invention. In this invention, even if it is 800 degrees C or less, the oxide containing layer useful for formation of the alpha type main body alumina film mentioned later can be formed.

Particular restrictions on the other conditions of the oxidation treatment is not, also to employ a method of irradiating addition to the thermal oxidation, with for example a plasma of an oxidizing gas such as oxygen, ozone, such as H ₂ O ₂ screen as specific oxidation as well as Valid.

It is preferable to perform the said oxidation treatment process in the film-forming apparatus of the alumina film used at the next process, and the method of performing the said thermal oxidation by raising a substrate temperature in the atmosphere of oxidizing gas is mentioned as a preferable embodiment.

<About the formation method of an alumina film in a 4th aspect>

Although the formation method of (alpha) type main body alumina film is not specifically limited, Since it is necessary to carry out in high temperature area of 1000 degreeC or more in CVD method, it is not preferable, and it is preferable to employ the PVD method which can form into a film in low temperature area. Although a sputtering method, an ion fritting method, a vapor deposition method, etc. are mentioned as a PVD method, sputtering method is especially preferable, and especially reactive sputtering is preferable because high speed film-forming can be performed using an inexpensive metal target.

In addition, although the base temperature at the time of alumina film formation is not specifically prescribed | regulated, when it carries out in the temperature range of about 650-800 degreeC, since an alpha-type main body alumina film easily forms, it is preferable. Further, following the oxidation treatment step, if the substrate temperature during the oxidation treatment is kept constant and the α-type main body alumina coating is formed, not only the characteristics of the substrate and the hard coating can be maintained but also the productivity is excellent.

It is preferable that the film thickness of the alumina film to form shall be 0.1-20 micrometers. It is because it is effective to secure 0.1 micrometer or more in order to maintain the outstanding heat resistance of this alumina film, More preferably, it is 1 micrometer or more. However, when the film thickness of an alumina film is too thick, it is unpreferable since internal stress will generate | occur | produce in the alumina film and cracks will arise easily. Therefore, it is preferable that the said film thickness shall be 20 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less.

<Film Formation Process in Fourth Aspect>

All processes of formation of the base film (when the base film is formed on the substrate), the gas ion bombard treatment, the oxidation treatment, and the formation of the alumina film mainly composed of the α-type crystal structure are the same. When performed in the apparatus, the treatment can be carried out continuously without moving the treatment, so that the member coated with the alumina coating of the α-type crystal structure main body can be efficiently manufactured.

In the same apparatus as described above, the gas ion bombard treatment and the oxidation treatment can be carried out without lowering the substrate temperature (about 350 to 600 ° C.) at the time of forming the base film. The time and energy required for heating can also be suppressed.

Specifically, a substrate made of cemented carbide, for example, is provided in a physical vapor deposition apparatus which is provided with an evaporation source for AIP, a magnetron sputtering cathode, a heater heating mechanism, a substrate rotating mechanism, and the like. After the film is formed by employing the AIP method or the like, Ar is introduced into the vacuum chamber, and a negative ion voltage is applied to the substrate to perform gas ion bombard treatment. Next, oxygen, ozone, and H ₂ 0 as described above are performed. The surface of the hard film is thermally oxidized in an oxidizing gas atmosphere such as ₂ , and thereafter, a reactive sputtering method or the like is employed to form an alumina film mainly composed of the α-type crystal structure.

(5) About the fifth sun

The present inventors further show that the alumina coating of the α-type crystal structure main body (hereinafter, also simply referred to as “α-type alumina coating”) on a hard coating such as TiAlN, which is a base coating, or various substrates such as cemented carbide or Si wafer, Drugs capable of maintaining the characteristics of the base material and base film (hereinafter, in the fifth aspect, the base material is previously formed on the base material unless otherwise specified), without forming a complicated intermediate layer. The study for forming in the temperature range below 800 degreeC was also performed.

As a result, in forming an alumina film, after performing a metal ion bombard process on the surface of a base material, it was found that what should just be an oxidation process, and came to the said this invention.

First, the manufacturing method of the alumina film of this invention is outlined. As a substrate capable of withstanding the temperature of the film forming process, for example, a substrate such as a carbide tool (uncoated), a Si wafer, or a hard coating such as CrN, TiN, TiAlN, diamond or the like is coated on the substrate as a base coating. When the metal ion bombard treatment is performed under the conditions described below, the accelerated metal ions collide with the substrate, and the etching of the surface of the substrate by the metal ions M is performed as shown in the enlarged view of FIG. The deposition of the metal ions M and the implantation (not shown) of the metal ions into the substrate occur simultaneously. As a result, in the vicinity of the base material 21 after the metal ion bombard treatment (the position of the base material surface before the metal ion bombard treatment is number 15), a concentration gradient layer in which the metal used for the metal ion bombard treatment is concentrated toward the surface layer side is increased. (22) is formed (Fig. 6 (b)).

Then, the surface of the concentration gradient layer 22 is oxidized to form an oxide-containing layer 23 as shown in Fig. 6 (c) on the surface of the concentration gradient layer 22, and then the alumina film 24 By forming the film, the member in which the oxide-containing layer 23 and the alumina film 24 of the α-type crystal structure main body were sequentially formed on the surface side of the concentration gradient layer 22 as shown in FIG. You can get it.

Such a method for producing an alumina film of the α-type crystal structure main body has the following features as compared with the conventional method shown in Japanese Patent Laid-Open No. 2002-53946.

(A) Since the concentration gradient layer formed by the metal ion bombard treatment is a metal layer whose surface is not nitrided or a metal layer in which a small amount of nitrogen or the like is dissolved, it is easier to oxidize compared with the conventional method of oxidizing a nitride film, and as a result, In addition, the time required for the oxidation treatment can be shortened, and the burden on the device due to heating can be reduced.

(B) The concentration gradient layer formed becomes a mixed layer with the base material as shown in FIG. 6 (b), and has a thickness of a layer other than the alumina film than the conventional method of forming a nitride film on the base material. It can be made thin and, as a result, the bad influence to the member characteristic by layers other than an alumina film can be suppressed.

In addition, since the concentration gradient layer formed is a mixed layer of a base material and a metal, there is no clear interface between a base material and this mixed layer, and it is essentially excellent in adhesiveness. Therefore, in order to improve adhesiveness with a base material more, it turns out that it is good to employ | adopt the said structure.

(C) Further, by performing the metal ion bombard treatment at a substrate temperature suitable for the oxidation treatment of the next step, the oxidation treatment can be quickly performed simply by making the atmosphere oxidizable, without performing additional radiation heating or the like to increase the substrate temperature. The productivity can be improved.

Hereinafter, the applicable conditions and very suitable conditions for forming an alumina film in this 5th aspect are explained in full detail.

<Metal ion bombard treatment>

As described above, in the formation of the alumina coating, the method of the present invention is characterized by first performing a metal ion bombard treatment on the surface of the substrate, and then subjecting the surface to an oxidation treatment, and specifying the detailed conditions of the metal ion bombard treatment. Although the following conditions are employ | adopted, the alumina of an alpha type crystal structure can be formed efficiently.

The use of a metal material that forms an oxide having a corundum structure as a source of metal ions is preferable since it is possible to easily form alumina having an α-type crystal structure. Examples of the metal material include Al, Cr, Fe, Or the alloy of these metals, the alloy which has these metals as a main component, etc. are mentioned. In addition, a metal in which the standard free energy of oxide formation is larger than aluminum may be selected, for example, Ti or the like can be used.

When a vacuum arc evaporation source is used for generation of metal ions, a large number of droplets are released as a drawback. In order to solve this problem, it is preferable to use a metal material having a relatively high melting point (for example, elements of Groups 4a, 5a, and 6a of the periodic table). In addition, if the method is performed without using a vacuum arc evaporation source as a method for generating metal ions, the above problem does not occur. Therefore, the metal material can be selected regardless of the melting point.

In view of the above, it is particularly preferable to use Cr, Ti or an alloy containing these as the generation source of the metal ions.

In addition, when forming a base film, when the target containing the metal which comprises the base film is used for a metal ion bombard process, the structure of a film-forming apparatus can be made simpler. For example, when forming a base film and its TiN, the method of performing metal ion bombardment process using a Ti target is mentioned.

The generation of metal ions may be performed by a method capable of generating a high ionized metal plasma. For example, a method of evaporating a metal target material by vacuum arc discharge using a vacuum arc evaporation source may be mentioned. As a vacuum arc evaporation source, it is especially preferable that the macro particle can be reduced by providing the mechanism of a filter.

In addition to generating the metal plasma using the vacuum arc evaporation source, a method of adding a metal ionization mechanism to, for example, a crucible ion frying method, or adding an RF (radio frequency) coil to the sputtering evaporation source. To improve the ionization rate, or a high-power pulse sputtering method for concentrating high power in a short time to promote ionization of steam.

In the case of performing the metal ion bombard treatment, it is necessary to apply a negative bias voltage to the substrate. By applying the bias voltage to the substrate, the metal ions generated in the vacuum arc evaporation source are energized to impinge on the surface of the substrate at high speed, and the substrate can be etched and the like as shown in the enlarged view of FIG. have.

The etching and the like can be realized even at a low voltage of about -100V, but preferably at least -300V. More preferably, a bias voltage of -600 V or higher is applied. Although the upper limit of the bias voltage is not specifically determined, the application of a high voltage too much may cause an arc discharge to cause damage to the substrate, and since X-rays may be required, the X-ray blocking measures of the apparatus are necessary. It is practical to set the upper limit to about -2000V, and the concentration gradient layer can be sufficiently formed even at -10OOV or less. The bias voltage may be applied continuously or intermittently.

In addition, when the surface on which the metal ion bombard treatment is performed is an insulating material such as diamond, cBN, or nitride, it is difficult to apply the bias voltage effectively, and the metal ion bombard treatment cannot be sufficiently performed. Therefore, in such a case, after forming a conductive layer on the substrate surface, applying a bias voltage or irradiating metal ions with a low bias voltage (about several tens of volts) to form a conductive metal-containing layer on the substrate surface, The bias voltage may be applied.

As described above, in addition to applying a DC voltage continuously or intermittently, a method of applying a bias voltage at a high frequency (1 to several hundred kHz) pulsed or applying RF may be employed, and these methods may be used as insulating surfaces. It may be employed to apply a bias voltage to the.

When using a vacuum arc evaporation source, it is common to perform metal ion bombard processing, without introducing an atmospheric gas. However, in view of ensuring the operational stability of the vacuum arc evaporation source, it may be an inert gas atmosphere such as Ar or a nitrogen atmosphere.

In the case of using the vacuum arc evaporation source, in order to prevent the macroparticles generated from the vacuum arc evaporation source from mixing in the formation layer, even if nitrogen is introduced with a small amount of reactive gas, for example, the treatment may be performed in a nitrogen atmosphere. do. However, in the case of using the reactive gas atmosphere in this manner, when the partial pressure of the reactive gas is more than 1 Pa, it becomes the same atmosphere as when the nitride film is formed, and the etching action is weakened, which is not preferable. Therefore, the reactive gas is preferably made to have a partial pressure of 0.5 Pa or less, preferably 0.2 Pa or less, and more preferably 0.1 Pa or less.

The metal ion bombard treatment is preferably performed by heating the substrate to 300 ° C or higher. Specifically, for example, after setting the substrate 2 to the substrate holder (oil-based rotation jig) 4 in the film forming apparatus shown in FIG. 7 to be described later, the substrate is evacuated until vacuum is obtained, and then the substrate. It is mentioned to raise the temperature of the base material 2 with the (copy) heater 5 while rotating the holder (oily rotating jig) 4.

By raising the substrate temperature in this manner, since the gas adsorbed on the surface of the substrate can be released before the start of the metal ion bombard treatment, arc generation during the metal ion bombard treatment can be suppressed, and stable operation can be performed.

In addition, since the substrate temperature during the metal ion bombard treatment is based on the energy corresponding to the bias voltage given to the substrate during the heating by the heater and the metal ion bombard treatment, the temperature rise during the metal ion bombard treatment is considered. Later, if the upper limit of the heating temperature by the heater is determined in advance, loss of energy or the like can be suppressed.

<About base material and base film in 5th aspect>

In the fifth aspect, a substrate constituting a member such as a cutting tool can be used as the substrate as it is, and in order to impart characteristics such as abrasion resistance, one having a single layer or a multilayer base film formed on the substrate in advance can be used. have. Although it does not prescribe to the specific kind of the base material and base film, in order to apply this method to manufacture of a cutting tool, a sliding member, a metal mold | die etc. which require excellent heat resistance and abrasion resistance, the following are preferable as the base material and base film. Is used.

As the substrate, various substrates such as copper materials such as high-speed steel, cemented carbide, cermet, sintered bodies containing cBN (cubic boron nitride) and ceramics, or hard materials such as crystalline diamond or Si wafers for electronic members can be used.

In the case of using the base film formed on the substrate, for example, at least one element selected from the group consisting of Group 4a, Group 5a and Group 6a, Al, Si, Cu and Y, C, of the periodic table, As a compound with at least one element of N, B, O, a mutual solid solution of these compounds, and a single substance or compound (for example, diamond grown on vapor phase, cBN, etc.) consisting of at least one element of C, N, B The film which consists of 1 or more types chosen from the group which consists of can be formed as a base film.

Representative of the base film, Ti (C, N), Cr (C, N), TiAl (C, N), CrAl (C, N), TiAlCr (C, N), that is, Ti, Cr, TiAl, Carbides, nitrides, carbon and nitrides of CrAl or TiAlCr, and are hard films commonly used for cutting tools and the like. For example, TiN, TiC, TiCN, TiAlN, CrN, CrAlN, TiAlCrN may be formed in a single layer or a multilayer. Can be.

In addition, a so-called thermal barrier coating such as oxide ceramics (for example, Yttrium Stabilized Zirconia) may be formed as the base film.

The film thickness of the base film is preferably 0.5 µm or more, more preferably 1 µm or more, in order to sufficiently exhibit wear resistance, heat resistance, and the like that is expected for the coating. However, when the base film is an abrasion-resistant hard film, if the film thickness is too thick, cracks are likely to occur in the film during cutting and the long life cannot be achieved, so the film thickness of the base film is 20 µm or less, more preferably. Preferably it is suppressed to 10 micrometers or less. When the base film is not the hard film as described above, the upper limit of the film thickness does not need to be particularly provided.

Although the formation method of the said base film is not specifically limited, In order to form a base film with favorable abrasion resistance, it is preferable to form by PVD method, and it is more preferable to employ AIP method or reactive sputtering method as the PVD method. Moreover, if the method of forming a base film by PVD method is employ | adopted, since a base film and the alpha-type main body alumina film mentioned later can be formed in the same apparatus, it is preferable also from a viewpoint of productivity improvement.

<About the oxidation treatment method in the fifth aspect>

In a fifth aspect, the base surface is oxidized after the metal ion bombard treatment. Although it does not specifically limit also about the conditions of the oxidation process, In order to form efficiently the oxide containing layer advantageous for production | generation of the alumina crystal nucleus of an alpha type crystal structure, it is preferable to oxidize on the following conditions.

That is, it is preferable to perform the said oxidation in oxidizing gas containing atmosphere. The reason for this is that the oxide can be efficiently oxidized. For example, an atmosphere containing an oxidizing gas such as oxygen, ozone or H ₂ O ₂ can be mentioned.

Moreover, it is preferable to perform thermal oxidation by maintaining the substrate temperature at 650 to 800 ° C. If the substrate temperature is too low, the oxidation is not sufficiently performed. Preferably, the substrate temperature is increased to 700 ° C or higher. Oxidation is accelerated by increasing the substrate temperature, but the upper limit of the substrate temperature needs to be suppressed to less than 1000 ° C in view of the object of the present invention. In this invention, even if it is 800 degrees C or less, the oxide containing layer useful for formation of the alpha type main body alumina film mentioned later can be formed.

In addition, if the oxidation treatment is continuously performed without cooling the substrate heated at the time of the metal ion bombard treatment, the time and energy required for heating can be suppressed. For that purpose, it is recommended to perform the oxidation treatment immediately after the metal ion bombard treatment with the oxidizing atmosphere in the apparatus.

A fifth particular restrictions on the other conditions of the oxidation process in the aspect is not, a method of irradiation by addition to the thermal oxidation as a specific oxidation methods, for example plasma of an oxidizing gas such as oxygen, ozone, such as H ₂ O ₂ Chemistry Of course, it is also effective to employ.

<About the formation method of the alumina film in 5th aspect>

Although the formation method of (alpha) type main body alumina film is not specifically limited, Since it is necessary to carry out in the high temperature area of 100 degreeC or more in CVD method, it is not preferable, and it is preferable to employ | adopt the PVD method which can form into a film in low temperature area. Although a sputtering method, an ion fritting method, a vapor deposition method, etc. are mentioned as a PVD method, sputtering method is especially preferable, Especially reactive sputtering is preferable because high speed film-forming can be performed using an inexpensive metal target.

In addition, although the base temperature at the time of alumina film formation is not specifically prescribed | regulated, when it carries out in the temperature range of about 650-800 degreeC, since an alpha-type main body alumina film easily forms, it is preferable. Moreover, when the base material temperature at the time of an oxidation process is kept constant and an alumina film is formed, since the characteristic of a base material and a hard film can be maintained, since productivity is also excellent, it is preferable.

It is preferable that the film thickness of the alumina film to form shall be 0.1-20 micrometers. It is because it is effective to secure 0.1 micrometer or more in order to maintain the outstanding heat resistance of this alumina film, More preferably, it is 1 micrometer or more. However, when the film thickness of an alumina film is too thick, it is unpreferable since internal stress will generate | occur | produce in the alumina film and cracks will arise easily. Therefore, it is preferable that the said film thickness shall be 20 micrometers or less, More preferably, it is 10 micrometers or less, More preferably, it is 5 micrometers or less.

<About the film-forming process in 5th aspect>

When all the steps of the metal ion bombard treatment, the oxidation treatment, and the formation of the alumina coating mainly composed of the α-type crystal structure are performed in the same apparatus, the treatment can be continuously performed without moving the treatment. , the member coated with the alumina film of the α-type crystal structure main body can be efficiently produced.

In the case where the base film is formed as the base material, all the steps of formation of the base film, the metal ion bombard treatment, the oxidation treatment, and the formation of the alumina film mainly composed of the α-type crystal structure are performed in the same apparatus. If performed, the formation of an alumina film mainly containing the metal ion bombard treatment, the oxidation treatment, and the α-type crystal structure is performed without lowering the substrate temperature (about 350 to 600 ° C.) at the time of forming the base film. Since the time and energy required for heating the base material can be suppressed, the member coated with the alumina film of the α-type crystal structure main body can be produced efficiently.

Specifically, a substrate made of cemented carbide, for example, is provided in a physical vapor deposition apparatus which will be described later, including, for example, an evaporation source for AIP, a magnetron sputtering cathode, a heater heating mechanism, a substrate rotation mechanism, and the like, and firstly, TiAlN is used as the base coating. After forming a hard film such as AIP method or the like, the metal ion bombard treatment with Cr ions is performed in a vacuum chamber, and then, an oxidizing gas atmosphere such as oxygen, ozone, H ₂ O ₂ or the like as described above. Among them, the surface of the hard film is thermally oxidized, and thereafter, a reactive sputtering method or the like is employed to form an alumina film mainly composed of the α-type crystal structure.

<About the coated member of the alumina film of the α-form crystal structure main body formed in the fifth aspect>

An alumina film mainly composed of an α-type crystal structure on a substrate (including a base film previously formed on the substrate) is a member formed in the fifth aspect, and is schematically illustrated in FIG. 6 (d). In the vicinity, the metal used for the metal ion bombard treatment is a concentration gradient layer which becomes higher concentration toward the surface layer side, and also defines a member in which an oxide-containing layer and an alumina film of the α-type crystal structure main body are sequentially formed on the surface side of the concentration gradient layer.

As the member of the present invention, specifically, for example, the substrate is made of cemented carbide, and the drawaway for turning or price in which TiN, TiCN, TiAlN, polycrystalline diamond, or cBN is formed as a base film (hard film). A tip or a drill or end mill in which the base is made of cemented carbide and formed TiN and TiCN as the base coating (hard coating), and a drawaway tip in which the base is made of cermet and TiN and TiCN is formed as the base coating (hard coating) Cutting tools, other semiconductor component parts of which the substrate is Si wafer, cBN sintered body tool, diamond tools, dies made of cemented carbide, or dies whose base film is formed on the base material; The metal mold | die in which the base film was formed on the base material is mentioned.

(6) About the sixth sun

As described above, O. Zywitzki, G. Hoetzsch, et al., "Surf. Coat. Technol. "[86-87 (1996) p. 640-647], by reactive sputtering using a pulsed power supply of high power (11-17 kW), to X-ray diffraction on an iron substrate at a substrate temperature of 700 to 760 캜. By observation, it has been reported that a film containing α alumina can be formed, and that the α film can be substantially formed at a substrate temperature of 750 to 770 ° C. Furthermore, O. Zywitzki et al. Observed the alumina film formed by the above-mentioned film formation in detail by transmission electron microscope (TEM), and reports the growth process of (alpha) alumina (Surf. Coat. Technol., 94 -95 (1997) p. 303-308).

On the other hand, Y. Yamada-Takamura et al., Which can form an α-alumina film at a substrate temperature of 780 ° C. by reactive film formation by a filter-type vacuum arc method, and apply an RF (radio frequency) bias to 460 It is reported that the production of α alumina is possible even at ℃ (Surf. Coat. Technol., 142-144 (2001) p. 260-264).

Also in this report, the alumina film cross section observation is performed by TEM, but similar to the report of O. Zywitzki et al.,? -Alumina is formed near the initial stage of the film growth (that is, the interface with the substrate in the film). As a result, detailed observations of the growth of α-alumina crystals have been reported.

Although all the techniques reported so far include γ-alumina at the initial stage of the growth of the coating, even if the coating partially contains γ-alumina in this way, when the coating member covering the coating is exposed to a high temperature of 1000 ° C. or higher, The gamma alumina of the part may cause phase transformation into alpha alumina. And since this phase transformation occurs with a volume change, there is a possibility that it may be the cause of cracking of the film. Moreover, when the phase transformation accompanying such a volume change arises at the interface of a film and a base material, it is anticipated enough that it will adversely affect the adhesiveness of a film.

As another technique, a method of enabling low temperature film formation of α alumina by using α-Cr ₂ O ₃ having the same crystal structure as α alumina as a template for crystal nucleation of α alumina (α-Al ₂ O ₃ ) It is proposed {for example, Unexamined-Japanese-Patent No. 2001-335917 (claim, Example, etc.), "J. Vac. Sci. Technol. ”(A20 (6), Nov / Dec, 2002, p. 2134-2136)}. According to Japanese Patent Application Laid-Open No. 2001-335917, by forming an α-Cr ₂ 0 ₃ base layer on a Si wafer, a film is formed in a vacuum atmosphere of about 2 × 10 ⁻⁶ Pa and a low film forming ratio of 1 nm / min. It is disclosed that α alumina is formed to a thickness of 0.18 μm at a substrate temperature of 400 ° C. as a requirement.

Further, for the purpose of solving the above-mentioned problem of processing temperature, Japanese Patent Laid-Open No. 2002-53946 discloses, for example, a corundum structure having a lattice constant of 4.779 GPa to 5.000 GPa and a film thickness of at least 0.005 µm. A method of forming an alumina film having an α-type crystal structure on the base layer using the oxide film as a base layer is disclosed. In addition, (Al _z , Cr _(1-z) ) N (where z is an intermediate layer on the formation of a composite nitride film of Al and at least one element selected from the group consisting of Ti, Cr and V as a hard film ₎ It is also disclosed that an oxide film having a corundum structure is formed by forming a film composed of O ≦ z ≦ 0.90) and oxidizing the film, and then forming alumina having an α-type crystal structure on the oxide film. Doing. In this method, crystalline α-alumina can be formed at a relatively low temperature of the substrate.

However, these Japanese Patent Application Laid-Open Nos. 2001-335917, 2002-53946, and "J. Vac. Sci. Technol. "(A20 (6), Nov / Dec, 2002, p. 2134-2136) also cannot detect the microcrystalline phase with respect to the alumina film formed, but is in the vicinity of an interface. The crystal structure of alumina is completely unknown. For this reason, in the alumina film | membrane formed by PVD method so far, (gamma) alumina exists in the area | region where the crystal | crystallization of an initial stage of film formation is minute, and it can be considered that alumina of an alpha type crystal structure is growing in such (gamma) alumina. .

Therefore, the present inventors have focused on the means for producing the alumina film substantially composed of the α crystal structure, focusing on the surface properties of the substrate (or the base film formed on the surface of the substrate), which becomes the crystal growth initiation portion of the alumina coating. .

As a result, the surface of the substrate is subjected to pretreatment such as ion bombard treatment or surface damage treatment with an oxide powder having a corundum structure, and a large number of fine wounds and depressions are formed on the substrate surface. When the oxidation treatment is carried out at a temperature of and the alumina film is formed thereafter, at least the growth initiation portion (that is, the interface between the oxide-containing layer and the alumina film) of the film is formed of an alumina crystal aggregate having a fine structure, In details, it was found that no crystal phase other than α-alumina was observed. Moreover, even if the above-mentioned pretreatment is not performed, when the oxidation treatment conditions (treatment temperature) are more strictly set, it has also been found that the alumina film formed thereafter is in the above crystalline form.

Such alumina film is composed only of α alumina, which is already the most thermally stable structure even when used in a high temperature atmosphere of 1000 ° C. or higher, so that it no longer causes crystalline transformation, Cracks, peeling, etc. do not occur.

In the alumina film of the present invention, it is preferable that crystals other than α-alumina are not observed not only at the film growth start point having a fine structure but everywhere, but the alumina film is formed by appropriately setting the treatment conditions. can do.

It is preferable that the film thickness of the alumina film of alpha type crystal structure shall be 0.5-20 micrometers, More preferably, it is about 1-5 micrometers. 0.5 micrometer is the thickness which corresponds to the "film growth start part" in this invention, and is the minimum thickness which the performance as a heat resistant film is exhibited. Moreover, by making film thickness into 20 micrometers or less, the bad influence (generation | generation of a crack) by the film internal stress can be avoided. Moreover, it is good to set it as 5 micrometers or less from a viewpoint of preventing the growing crystal from becoming extremely coarse.

In the sixth aspect, as the means for forming the alumina film having the α-type crystal structure, the CVD method needs to be performed at a high temperature of 1000 ° C or higher, which is not preferable, and the PVD method which can form a film in a relatively low temperature region is adopted. Among these PVD, sputtering method, particularly reactive sputtering method, is suitable for forming a high insulating film such as alumina at a reasonable film forming rate and is preferable in terms of productivity. The film-forming speed | rate at this time can be ensured at least 0.1 micrometer / hr or more, and may be 0.5 micrometer / hr or more in order to raise productivity more.

In addition, although the optimal substrate temperature at the time of forming the said alumina film differs by presence or absence of pretreatment, the kind of base material, base film, etc., when performing pretreatment, it is necessary to ensure at least 700 degreeC or more. If the temperature is lower than this, it is difficult to form an alumina film having an α crystal structure.

On the other hand, from the viewpoint of "lower temperature of the process" which can be mentioned as one of the objectives of forming alpha alumina by the PVD method, for example, 800 ° C in which the characteristics of a film such as TiAlN, which may be formed as a base film, do not deteriorate. It is preferable to form alumina below. In addition, the "substrate temperature" used here means the temperature of the base material formed on cemented carbide, carbon steel, tool copper, etc., and the base material.

In the sixth aspect, prior to the formation of the alumina film, an oxide-containing layer is formed by oxidizing (oxidizing) the surface of the substrate or the surface of the base coating film previously formed on the substrate. This oxidation treatment step is performed in an apparatus (vacuum chamber) for forming an alumina film to be formed in the next step from the viewpoint of treatment efficiency or from the viewpoint of preventing adsorption of water vapor in the atmosphere to the formed oxide-containing layer surface. It is preferable that thermal oxidation is carried out by raising the substrate temperature in an atmosphere of an oxidizing gas. As the oxidizing gas atmosphere at this time, for example, there may be mentioned an atmosphere containing an oxidizing gas such as oxygen, ozone, such as H ₂ O _2, among them also are included as well as an air atmosphere.

In addition, although the optimal substrate temperature differs depending on the presence or absence of pretreatment, the type of substrate or base coating, and the like, for example, when the base coating is CrN and pretreatment of gas ion bombard or damage is performed, at least 700 ° C or more. It is necessary to carry out thermal oxidation by maintaining it. On the other hand, for example, when the base coating is CrN and no pretreatment is performed, or when the base coating is TiAlN and pretreatment of gas ion bombard or damage, or the base or base is not limited, the metal ion spring by Cr In the case of performing the pretreatment by the bard, it is necessary to perform the oxidation treatment at a substrate temperature of 750 ° C or higher. If the substrate temperature is too lower than the above-mentioned temperatures, the oxidation is not sufficiently performed, and the desired α-alumina is not formed even if the alumina film forming conditions are appropriate.

Oxidation is accelerated by increasing the substrate temperature, but the upper limit of the substrate temperature needs to be suppressed to less than 100 ° C in view of the object of the present invention. The oxide containing layer useful for formation of the alumina film of this invention can be formed also at 800 degrees C or less. Therefore, in order to obtain the alpha-alumina coating of the present invention, the substrate temperature in the oxidation treatment step and the alumina coating film formation step is set continuously according to the presence or absence of pretreatment (preferably in the same apparatus). The same substrate temperature).

In forming the alumina film in the sixth aspect, there are no particular restrictions on the conditions other than the substrate temperature in the oxidation treatment, and specific examples of the oxidation method include oxygen, ozone, H ₂ O in addition to the thermal oxidation. _It is of course also effective to employ a method of irradiating an oxidizing gas such as ₂ into a plasma. When the oxide containing layer is formed as described above, a film of alumina having an α-type crystal structure can be reliably formed on the surface thereof.

In the sixth aspect, in producing the alumina film, pretreatment such as gas ion bombard treatment or surface damage treatment with oxide powder of corundum structure is performed on the surface of the substrate as necessary. By carrying out such pretreatment, even in the case where subsequent oxidation treatment and alumina film formation are performed at a relatively low temperature (700 ° C. or more), an alumina film having an α crystal structure can be obtained. The action by these pretreatments can be considered as follows.

In the ion bombard process, as described above, in the state in which an inert gas such as Ar is introduced into the vacuum chamber, a negative bias voltage (direct current voltage or high-frequency alternating voltage) is applied to the substrate to generate a glow discharge. The substrate surface is etched by colliding gas ions such as Ar in the plasma generated by the glow discharge with the substrate at high speed. By this treatment, the number of generation points (oxide points) of the alumina crystal nucleus of the α-type crystal structure formed in the oxidation treatment of the next step is formed more uniformly.

On the other hand, the surface damage treatment by the oxide powder of corundum structure is a base material in the liquid which grind | polished the surface of a base material or disperse | distributed the powder using the alumina powder of (alpha) type crystal structure (corundum structure), for example. Ultrasonic application is performed by dipping to form fine scratches or depressions in the shape reflecting the shape of the powder on the surface of the substrate.

In addition, by this treatment, a trace amount of alumina powder having an α-type crystal structure may remain on the surface of the substrate. As a result of these wounds, depressions, or the presence of a very small amount of alumina powder, the formation points (oxide points) of the alumina crystal nucleus of the α-type crystal structure formed in the oxidation treatment of the next step as described above are formed more uniformly.

As the powder used in such a treatment, not only an alumina powder having an α-type crystal structure but also a powder having a corundum structure such as Cr ₂ O ₃ or Fe ₂ O ₃ can be used. It is preferable to use an alumina powder having an α-type crystal structure such as a film. In addition, from the viewpoint of forming a fine alumina film, the powder is preferably one having a smaller size, preferably having an average particle diameter of 50 µm or less, more preferably 1 µm or less.

Moreover, the said metal ion bombard process is mentioned as another pretreatment method. The metal ion bombard treatment, as described above, evaporates the metal target material by, for example, a vacuum arc discharge using a vacuum arc evaporation source, imparts energy to the produced metal ions at a bias voltage to impinge the substrate at a high temperature. On the most surface, it forms a mixed layer of the base material (or base layer) with a lot of said metal content, and the said metal.

Moreover, in order to fully exhibit the wear resistance anticipated as a hard film, the film thickness of the base film at this time is preferably set to 0.5 µm or more, and more preferably 1 µm or more. However, if the film thickness of the base film is too thick, the base film is easily cracked at the time of cutting, and the long life cannot be achieved. Therefore, the film thickness of the hard film is 20 μm or less, more preferably 10 μm or less. It is good to suppress.

As another kind of base coating, so-called thermal barrier coating such as oxide ceramics (for example, Yttrium Stabilized Zirconia) may be used. In this case, there is no restriction in particular in the film thickness.

Although the formation method of the said base film is not specifically limited, In order to form a hard film with favorable abrasion resistance, it is preferable to form by PVD method, and it is more preferable to employ AIP method or reactive sputtering method as the PVD method. In addition, if the method of forming the base film by the PVD method is adopted, film formation can be performed in the same apparatus for formation of the base film and the formation of the α-alumina film, which is also preferable from the viewpoint of productivity improvement.

(7) About film forming apparatus (physical vapor deposition apparatus)

As described above, for example, the α-alumina may be formed on a TiAlN-based, which is frequently used as a hard coating, or on a hard coating such as TiN or TiCN without forming a special intermediate layer such as a base layer for forming a corundum structure oxide. As a result, as described above, the surface of the hard film such as TiAlN, TiN, TiCN or the like formed on the surface of the substrate is exposed to an oxidizing atmosphere of about 650 ° C. to 80 ° C. as a result. Then, it turned out that it is good to form an alumina film at the temperature of about 650 degreeC-800 degreeC, for example by the reactive sputtering method.

In addition, particularly in the case of forming an alumina film mainly composed of an α-type crystal structure on the TiAlN film, the surface of the film is subjected to a bombard treatment, after which the surface is exposed to an oxidizing atmosphere of 650 ° C. to 80 ° C. When the alumina film was formed at a temperature of about 650 ° C. to 80 ° C. by the reactive sputtering method, it was found that crystal phases other than the α-type crystals were reduced, and a finer and finer alumina film was obtained with crystal grains.

The inventors of the present invention have also conducted studies on the apparatus to be used in order to realize such an effect of the present invention concretely and efficiently. As a result, the present invention provides practical hard coatings such as TiN, TiCN, TiAlN, and the like. Base oxide film), which is capable of efficiently and stably forming a high-purity oxide film having excellent high heat resistance, such as an alumina film mainly composed of an α-type crystal structure, without arranging the special intermediate layer. It was found that all treatment steps leading to formation can be performed in the same apparatus. Hereinafter, the physical vapor deposition apparatus of this invention which could achieve the said subject is explained in full detail.

First, the outline | summary of embodiment of this invention is demonstrated. The apparatus of the present invention has a vacuum chamber, a substrate holder (oil-based rotary jig), an inert gas and an oxidizing gas introduction mechanism, a plasma source, a sputtering evaporation source, a radiant superheating mechanism, and a bias power supply, respectively, as its basic configuration.

The substrate holder (oil-based rotary jig) is for storing a plurality of substrates, and is disposed on the bottom of the vacuum chamber as a rotating material. A rotary table is disposed on the bottom surface of the vacuum chamber, and a plurality of substrate holders (oil-based rotary jigs) are provided on the rotary table, and it is preferable that the rotary table is provided on a rotary table as a rotating (rotating) material. Moreover, it can also be arrange | positioned at the upper surface instead of the bottom surface of a vacuum chamber.

In addition, the inert gas and the oxidizing gas introduction mechanism are provided for making the atmosphere in the vacuum chamber the inert gas and / or the oxidizing gas. The introduction mechanism is an introduction pipe connecting these gas sources and the upper portion of the vacuum chamber, and each includes a flow rate regulating valve. As said inert gas, argon can be used, for example. Argon is excited by the plasma source to generate an argon plasma, and the surface of the hard film (base film) such as TiAlN, TiN, TiC, etc., which are used as the base material, is ion bombarded to clean the surface. There is a number.

Oxygen, ozone, hydrogen peroxide, etc. can be used as said oxidizing gas, and the said hard film (base film) after cleaning can be oxidized by supplying these gases in a vacuum chamber. When a mixed gas of this oxidizing gas and an inert gas such as argon is supplied into the vacuum chamber, it becomes a plasma gas, which forms a film by reactive sputtering, that is, has an α-type crystal structure on the surface of the hard film (base film). It is possible to form high heat-resistant oxide-based coatings such as so-called alumina.

The plasma source is provided with a mechanism for generating a plasma gas for film formation by the ion bombard treatment or reactive sputtering, and is disposed at a position opposite to the substrate holder (oily rotating jig). As this plasma source, various types such as filament excitation, holocathode discharge, and RF discharge can be used.

The sputtering evaporation source is a cathode of a target material used for reactive sputtering, and is preferably disposed at a position opposite to the ear canal substrate holder (oily rotating jig). Metal aluminum is used when forming high heat resistant films, such as (alpha) alumina.

The radiant heating mechanism is provided to heat the substrate to a predetermined temperature, and is preferably disposed at a position opposite to the substrate holder (oil-based rotating jig). The heating ability of this radiation type heating mechanism needs to be able to heat up and hold | maintain the base material supported by a base material holder (oily rotational jig) at 650-800 degreeC. The surface of the hard film (base film) can be sufficiently oxidized by heating the hard film (base film) previously formed on the surface of the substrate to a temperature of 650 to 800 ° C.

Moreover, the film formation on the hard film (base film) of the said high heat resistant film by reactive sputtering performed following the said oxidation process can also be advantageously achieved by heating and holding in this temperature range.

The formation of a high heat resistant film by thermal oxidation or reactive sputtering of such a hard film (base film) is insufficient and less than 650 ° C. On the other hand, in the oxidation treatment step and the alumina film forming step (reactive sputtering step), the oxidation treatment and the alumina film can be formed without the radiation heating mechanism exceeding 800 ° C. Moreover, when it is set as the high temperature over 800 degreeC, there exists a possibility that the characteristic of a hard film may deteriorate. However, in the same apparatus, when a hard film such as TiAlN, TiN, TiC or the like is formed on the substrate by adopting the AIP (Arc Ion Plating) method, the radiant heating mechanism provides a heating capability suitable for the implementation of the AIP method. It is preferable to have.

The bias power supply connected to the substrate holder (planetary rotational jig) needs to be able to apply a negative pulsed bias voltage to the substrate holder (planetary rotational jig). Thereby, in the ion bombard process, even when using the base material holder (oil-based rotation jig) with an insulating film, a stable voltage can be applied.

In addition, an arc evaporation source may be included as the configuration of the apparatus. An arc evaporation source is also disposed at a position opposite to the substrate holder (oil-based rotation jig) similarly to the sputtering evaporation source. By providing this arc evaporation source, the film formation by the said AIP is also enabled by this apparatus.

Next, the specific example of embodiment of this invention is described in detail, referring drawings. 8 is a cross-sectional explanatory view of the physical vapor deposition apparatus of the present invention. In the apparatus, a circular rotary table 3 is provided in the vacuum chamber 1 having a regular octagonal cross section (cross section), and on the circular rotary table 3, a plurality ( In the drawing example, six substrate holders (the planetary rotational jig) 4 hang. The base material 2 to be processed is stored in the base holder (planetary rotation jig) 4 and is planetary rotated by the rotation of the rotary table 3 and the rotation of the base holder (planetary rotation jig) 4. It is a mechanism.

In addition, a cylindrical radiant heating heater 51 is disposed in the center of the rotary table 3, that is, the inner center of the substrate holder (the planetary rotary jig) 4, while the inside of the vacuum chamber 1 is disposed. On two opposite surfaces of the side surfaces 8, planar radiant heating heaters 51, 52 respectively facing the substrate holder (oil-based rotary jig) 4 face each other with the rotary table 3 interposed therebetween. It is provided in this state and these 51 and 52 comprise the base material heating mechanism 5.

Inside the radiant heating heater 52, a plasma source 8 (shown in the drawing shows a filament provided for plasma generation) for exciting an atmosphere gas with a plasma gas is further provided. Sputtering evaporation sources 6 and 6 for reactive sputtering are provided on the two surfaces of the other inner side facing each other with the rotary table 3 interposed therebetween at a position opposite to the substrate holder (oily rotating jig) 4. have. In addition, on the two surfaces of the other inner side surface of the vacuum chamber 1, the arc evaporation sources 7 and 7 for AIP are placed between the rotary tables 3 at positions opposite to the substrate holders (the planetary rotary jig) 4 in the same manner. It is installed in a state facing each other. In addition, since these arc evaporation sources 7 and 7 may not be needed, they are shown with the dotted line in the figure.

Then, at an appropriate position above the vacuum chamber 1, a gas introduction pipe 11 for introducing an inert gas 9 for plasma generation or an oxidizing gas 10 for oxidation treatment into the chamber communicates with each other. The exhaust gas pipe 13 for discharging the exhaust gas 12 after the vacuum exhaust or the process is connected to the appropriate position of the lower part of the same vacuum chamber 1 in communication.

In Fig. 8, reference numeral 14 denotes a bias power supply capable of being connected to a substrate holder (planetary rotational jig) 4 and capable of applying a negative pulsed bias voltage (10OV to 20OOV) to the substrate holder (planetary rotational jig) 4. It is shown.

According to the present embodiment, as described above, the substrate holder (oil-based rotary jig) 4, the inert gas and the oxidizing gas introduction mechanism, the plasma source, the sputtering evaporation source 6, the arc evaporation source 7, and the like in the vacuum chamber 1, Since the radiant heating heaters 51 and 52 and the bias power source 14 are disposed, a step of forming a base film such as a hard film on the surface of a substrate such as a tool or a wear-resistant member by AIP, the hard film A process of ion bombarding the surface of the base coating, such as, followed by thermal oxidation of the surface of the base coating, such as the hard coating, and reactive sputtering on the surface of the hard coating after the thermal oxidation treatment. All processes related to the physical vapor deposition treatment, such as the process of forming a high heat resistant oxide based film, can be performed in a single apparatus.

In addition, the rotary table 3 and the plurality of substrate holders (the planetary rotating jig) 4 provided on the table can cause the substrate 2 to be planetary rotated in the chamber 1, and therefore the angle The process of the base material 2 in a process can be performed uniformly. In other words, the hard coating can be ion bombarded or thermally oxidized at a constant rate over the entire surface of the substrate, and even in the formation of a hard or oxidized coating by reactive sputtering or AIP. Can be formed. Thereby, the high heat resistant film excellent in adhesiveness can be obtained.

Moreover, by equipping both of the radiant heating heaters 51 and 52, the base material 2 which circulates and passes along with the rotation of the rotary table 3 is carried out by the center side of the same table 3 and the chamber 1 of the same. It can simultaneously heat effectively from the inside and the outside of the wall side, and can improve productivity in processing processes, such as thermal oxidation and film-forming. In addition, by connecting a bias power supply 14 capable of applying a negative pulse-like bias voltage to the base holder (planetary rotational jig) 4 and providing it, insulation property is maintained with continuous use of the base holder (planetary rotational jig) 4. Even when an alumina film or the like which is easy to be formed is formed on the base holder (oil-based rotary jig) 4 or the like, a stable voltage can be applied without causing an arc discharge or the like causing charge up. By forming a film in which voltage application is stable in this manner, a product such as a cutting tool having a high adhesion film can be obtained as a result.

In the present embodiment, a square octagonal vacuum chamber 1 is employed, and necessary components such as a sputtering evaporation source 6, an arc evaporation source 7, and a planar radiant heating heater 52 are provided. Since it is the structure arrange | positioned at six inner surface of the same chamber 1 so that each pair may face each other, it becomes the compact apparatus which wastes no space.

9 and 10 are cross-sectional explanatory views of a physical vapor deposition apparatus showing a specific embodiment, but since the basic configuration is common to that of FIG. 8, the configuration different from that of FIG. 8 will be described.

In the apparatus of FIG. 9, the cross-sectional shape of the vacuum chamber 1 is a regular hexagon, and the sputtering evaporation source 6, the arc evaporation source 7 and the planar radiant heating heater 52 are provided on all six inner surfaces of the chamber 1. Similarly, each has a structure in which a pair is provided to face each other. In addition, in the apparatus of FIG. 9, the cross-sectional shape of the vacuum chamber 1 has a square shape, and in this case, the sputtering evaporation source 6 and the planar radiant heating heater 52 are all four of the same chamber 1. The inner side faces each other, and a pair is provided.

The embodiment of Figs. 9 and 10 can be made more compact than the embodiment of Fig. 8. In addition, in the aspect of FIGS. 8-10, although the front surface which opposes the base holder (oil-based rotation jig | tool) 4 is flat, the shape of the radiation type heating heater 52 is not limited to this, For example, A curved surface can be adopted in accordance with the curvature of the main surface of the turntable 3. In addition, the arrangement of the plasma source 8 may not be in front of the same heater 52.

Example

Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not restrict | limited by the following example originally, It is also possible to change suitably and to implement in the range which may be suitable for the purpose of the previous and the later. It is possible that they all fall within the technical scope of the present invention.

(1) Example according to the first aspect

<First Embodiment>

First, the embodiment regarding the said 1st means (the aspect of 1st (1) (2)) is shown. A substrate made of a cemented carbide alloy with a size of 12.7 mm x 12.7 mm x 5 mm was subjected to mirror polishing (Ra = 0.02 µm), ultrasonically cleaned in an alkali bath and a pure water bath, and then dried to coat the laminated film.

In this embodiment, the hard film was formed, the hard film was oxidized, and the α-type main body alumina film was formed in the vacuum film forming apparatus (AIP-S40 multifunction device manufactured by Shinzo Steel Co., Ltd.) shown in FIG. 4. .

Formation of the hard film on the substrate is performed by the AIP method (Arc Ion Plating) using the AIP evaporation source 7 in the apparatus 1 shown in FIG. A TiAlN hard film having an atomic ratio of Al (Ti: Al) of O.55: O.45 or a TiAlCrN hard coating having an atomic ratio of Ti, Al and Cr (Ti: Al: Cr) of 0.10: 0.65: 0.18 It was. Further, as a first comparative example, a CrN film was formed on the TiAlN film and by the AIP method.

Oxidation of the hard film or oxidation of the CrN film formed on the hard film was performed as follows. That is, the sample (substrate) 2 is set in the base holder (oil-based rotation jig) 4 on the rotary table 3 in the apparatus 1, and the apparatus is evacuated until it is almost vacuum, and then the inside of the apparatus is The sample was heated with the heater 5 provided in two places and the center part of the side until it became the temperature (substrate temperature in an oxidation process process) shown in Table 1. When the temperature of the sample became a predetermined temperature, oxygen gas was introduced into the apparatus 1 so as to have a flow rate of 200 sccm and a pressure of 0.5 Pa, and heated and stored for 20 minutes or 60 minutes for oxidation.

In addition, the hard film formation, oxidation treatment, and alumina film formation described later are performed on the substrate holder (oil rotating jig) 4 provided thereon while rotating (revolving) the rotary table 3 in FIG. 4. The rotation was carried out while rotating (rotating). In this embodiment, oxidation treatment and alumina film formation are performed while rotating the rotating table 3 at 3 rpm and rotating the substrate holder (oil rotating jig) 4 at 20 rpm.

Next, an alumina film mainly composed of the α-type crystal structure was formed on the oxide-containing layer. The alumina film is formed in an argon and oxygen atmosphere at a substrate temperature approximately equal to that of the oxidation treatment step, and is approximately 3 kW on the sputtering cathode 6 equipped with one or two aluminum targets in FIG. The pulsed DC electric power was applied and the reactive sputtering method was employ | adopted. In addition, at the time of formation of an alumina film, the sample (substrate) temperature rose slightly compared with the oxidation process. In addition, the formation of the alumina coating was performed by controlling the discharge voltage and the argon-oxygen flow rate ratio by using plasma emission spectroscopy, and making the discharge state the so-called transition mode.

The surface of the laminated film thus formed was analyzed by a thin film X-ray diffraction apparatus to identify the crystal structure of the alumina film formed as the most surface film. That is, from the X-ray diffraction measurement results shown in FIG. 11 and FIG. 12 described later, a peak intensity Iα of 2θ = 25.5761 (°) is selected as an X-ray diffraction peak representing alumina having an α-type crystal structure, and the γ-type A peak intensity Iγ of 2θ = 19.4502 (°) was selected as an X-ray diffraction peak representing alumina of the crystal structure, and the degree of alumina formation of the α-type crystal structure was evaluated from the magnitude of this intensity ratio: Iα / Iγ value. These results are written together in Table 1.

Hard coating Oxidation process Film Formation Process of Alumina Membrane Measurement result of alumina membrane Substrate temperature Heating time power The number of sputters used Substrate temperature Thickness Iα / Iγ Crystal structure Inventive Example 1 TiAlN 760 ℃ 20 minutes 3 kW 2 units 780 ℃ 2 μm γ peak not detected ^{※ 1} α type Comparative Example 1 TiAlN + CrN 2 μm γ peak not detected ^{※ 1} α type Inventive Example 2 TiAlN 750 ℃ 20 minutes 3 kW 1 unit 770 ℃ 1.15 μm 2.8 α type, γ type Inventive Example 3 TiAlCrN 1.15 μm 2.9 α type, γ type Inventive Example 4 TiAlN 740 ℃ 60 minutes 3 kW 1 unit 770 ℃ 0.9 μm γ peak not detected ^{※ 1} α type Comparative Example 2 TiAlN 635 ℃ 20 minutes 3 kW 1 unit 670 ℃ 1.3 μm 1.4 α and γ mixture Comparative Example 3 TiAlN 580 ℃ 20 minutes 3 kW 2 units 590 ℃ 2 μm α peak not detected ^{※ 2} γ type

* 1 No peak detected at 2θ = 19.4502 °

* 2 No peak detected at 2θ = 25.5761 °

Fig. 11 is the result of measuring the surface of the laminated film of the first example of the present invention with a thin film X-ray diffractometer. Since the main peak of X-ray diffraction shown in FIG. 11 is a diffraction peak attributable to TiAlN and a diffraction peak of alumina having an α-type crystal structure formed on the most surface, the film of the first example of the present invention is α-type on the hard film. It can be seen that the alumina film of the crystal structure principal was formed.

Fig. 12 shows the thin film X-ray diffraction results of the surface of the laminated film of Comparative Example 1, wherein the diffraction peak due to Cr ₂ 0 ₃ formed by oxidizing CrN as an intermediate film together with the diffraction peak of alumina having an α-type crystal structure. Is observed.

From this, it can be seen that also in the first comparative example, an alumina film of the α-type crystal structure main body is formed in the same manner as in the first invention example. However, the hard film according to the present invention is excellent in that the productivity of the laminated film is further improved by omitting the step of forming the intermediate film, in addition to not having to worry about a decrease in cutting performance due to the Cr-containing film formed as the intermediate film.

In the second invention example and the third invention example, TiAlN or TiAlCrN is formed on the substrate as a hard film, and only the substrate temperature of the oxidation treatment step is set at 750 ° C, which is 30 ° C lower than the first invention, and other conditions Is formed in the same manner as in the first embodiment of the present invention. As shown in Table 1, in the 2nd this invention example and 3rd this invention example, although the alumina of a (gamma) type crystal structure is mixed in the formed film slightly, it turns out that the alumina film of (alpha) type main body is formed.

In addition, the fourth embodiment of the present invention forms TiAlN as a hard film, sets the substrate temperature in the oxidation treatment step to 740 ° C. lower than those of the second and third invention examples, and reduces the oxidation treatment time. 60 minutes longer than the 1st-3rd this invention example, and other conditions were formed into a film in the same manner as the 1st this invention example. As shown in Table 1, it can be seen that the outermost surface of the film obtained in the fourth example of the present invention is covered with almost pure α-type crystal structure alumina.

In the second comparative example and the third comparative example, the oxidation treatment temperature was set to 635 ° C in the second comparative example and 580 ° C in the third comparative example, and all of them were heated and stored for 20 minutes. When the oxidation treatment is performed at 580 ° C. than the results of the third comparative example shown in Table 1, no alumina film having an α-type crystal structure is formed at all, even if an alumina film is formed thereafter, and an alumina film having a γ-type crystal structure is formed. It can be seen that. In the second comparative example, when the oxidation treatment was performed at 635 ° C., the crystal structure of the alumina film formed was slightly superior in the α type, but was substantially mixed in the α type and the γ type, and thus the α type main body. Is hard to do.

Second Embodiment

Next, the Example regarding the said 2nd means (1st aspect) is shown.

A substrate made of a cemented carbide alloy having a size of 12.7 mm × 12.7 mm × 5 mm was mirror polished (about Ra = 0.02 μm), ultrasonically cleaned in an alkali bath and a pure water bath, and then dried, which was used for coating the laminated film.

Also in this embodiment, similar to the first embodiment, the vacuum film forming apparatus shown in Fig. 4 shows the formation of a hard film, oxidation of the hard film, and formation of an α-type main body alumina film. Product AIP-S40 multifunction machine).

Formation of the hard film on the substrate is performed by the AIP method (Arc Ion Plating) using the AIP evaporation source 7 in the apparatus 1 shown in Fig. 4, and the TiN film having a film thickness of 2 to 3 m or A TiCN film was formed on the substrate. As a reference example, CrN having the same film thickness was formed on a substrate.

Oxidation of the coating was carried out as follows. That is, the sample (substrate) 2 is set in the base holder (oil-based rotation jig) 4 on the rotary table 3 in the apparatus 1, and the apparatus is evacuated until it is almost vacuum, and then the inside of the apparatus is The sample was heated to around 760 degreeC with the heater 5 installed in two side surfaces and the center part of the. When the temperature of the sample became about 760 degreeC, oxygen gas was introduce | transduced into the apparatus 1 so that it might become a flow volume of 200 sccm, and the pressure of 0.5 Pa, and it heated and maintained for 20 minutes, and was oxidized.

In addition, the hard film formation, oxidation treatment, and alumina film formation described later rotate (rotate) the rotary table 3 in FIG. 4, and at the same time, a substrate holder (oil-based rotary jig) 4 provided thereon. The rotation was carried out while rotating (rotating). In this embodiment, oxidation treatment and alumina film formation were performed while rotating the rotating table 3 at 3 rpm and rotating the substrate holder (oil rotating jig) 4 at 20 rpm.

Next, an alumina film mainly composed of the α-type crystal structure was formed on the oxide-containing layer. Formation of the alumina film is performed in an argon and oxygen atmosphere, and the substrate temperature is about the same as that of the oxidation treatment step, and an average of 5.6 kW pulse DC is applied to the sputtering cathode 6 equipped with two aluminum targets in FIG. The reaction was performed by applying a reactive sputtering method by applying electric power. In addition, at the time of formation of an alumina film, the sample (substrate) temperature rose slightly compared with the oxidation process.

In addition, the formation of the alumina coating was performed by controlling the discharge voltage and the argon-oxygen flow rate ratio by using plasma emission spectroscopy, and making the discharge state the so-called transition mode.

The surface of the laminated film thus formed was analyzed by a thin film X-ray diffractometer (thin film XRD analysis) to identify the crystal structure of the alumina film formed as the most surface film. The thin film X-ray diffraction result of using a TiN film (1st 'invention example) is shown in FIG. 1, and the thin film X-ray diffraction result of using a TiCN film (2nd' invention example) is shown in FIG.

In the same manner as in the first example, the Iα / Iγ value was determined from the thin film X-ray diffraction results of FIG. 1 or 13 to evaluate the degree of alumina formation in the form crystal structure. This result is shown in Table 2 with the said film-forming conditions.

Hard coating Oxidation process Film Formation Process of Alumina Membrane Measurement result of alumina membrane Substrate temperature Heating time Substrate temperature Average discharge power (two total) Tabernacle Time Thickness Iα / Iγ Crystal structure Inventive Example 1 TiN 760 ℃ 20 minutes 770 ℃ 5.6 kW 3 hours 2 μm γ peak not detected ^※ type α, type γ species Inventive Example 2 TiCN γ peak not detected ^※ type α, type γ species Reference Example CrN Iα / Iγ = 6.4 type α, type γ species

※ No peak of 2θ = 19.4502 ° is detected

The main peaks of the X-ray diffraction shown in Figs. 1 and 13 are the diffraction peaks and the most surface due to the TiN film or the TiCN film (in addition, in Fig. 13, only the TiN structure in the TiCN film is detected by thin film X-ray diffraction). X-ray diffraction peaks (2θ = 19.4502 °) representing the alumina of the γ-type crystal structure, which are the diffraction peaks of the alumina of the α-type crystal structure formed in the above, and from Figs. In addition, since the peaks showing the alumina of the other γ-type crystal structure are also small, it can be seen that the laminated films of the first 'invention examples and the second' invention examples are formed of an alumina film of the α-type crystal structure main body on the hard film. have.

1 and 13, the peak of Ti ₃ 0 ₅ , which is thought to have been reduced and formed after the oxidation treatment of the coating between the TiN coating or the TiCN coating and the alumina coating, can be confirmed.

On the other hand, the reference example is an example in which an alumina film is formed on a CrN film containing Cr, which is a metal having a standard free energy of less than aluminum, as a metal component. It is understood that the formed alumina film has a higher ratio of γ-type crystal structure alumina than that of the alumina of the α-type crystal structure.

(2) Example concerning a 2nd aspect

First, the various intermediate | middle layers of following (A)-(E) were formed previously on the cemented-carbide base material.

(A) Cr metal film: 0.1 탆 thick (formed by AIP method)

(B) Ti metal film: film thickness of 0.1 탆 (formed by AIP method)

(C) TiAl film: film thickness 0.1 μm (Ti: Al = 50: 50, formed by sputtering method)

(D) Fe film (contains Cr and Ni): film thickness of 0.1 탆 (film formation by sputtering method using SUS304 target)

(E) CrN _x film: film thickness of 3 µm [formed by evaporation of chromium at nitrogen pressure: 0.13, 0.35, 0.35, 1.3 or 2.7 (Pa) by AIP method]

Moreover, about the chromium nitrogen coating of said (E), composition analysis by XPS (X-ray photoelectron spectroscopy) and crystal structure analysis by XRD (X-ray diffraction) were performed. The results are shown in Table 3 below. Among those shown in Table 3, the CrN film formed at a pressure of 2.7 Pa is close to the stoichiometric composition (x in CrNx is 0.96), which corresponds to the prior art.

Deposition pressure (Pa) Furtherance Crystal tissue 0.13 Cr: N = 1: 0.31 Cr + Cr ₂ N 0.27 Cr: N = 1: 0.59 Cr ₂ N 0.65 Cr: N = 1: 0.75 Cr ₂ N + CrN 1.3 Cr: N = 1: 0.85 CrN 2.7 Cr: N = 1: 0.95 CrN

Next, the film formation of this invention was performed using the PVD apparatus (vacuum film-forming apparatus) shown in said FIG. That is, the sample (substrate) 2 is set in the substrate holder (oily rotating jig) 4 in the apparatus 1, and the exhaust gas is evacuated until the inside of the apparatus 1 becomes almost vacuum, and then the side surfaces of the apparatus and The sample was heated to 750 degreeC with the heater 5 arrange | positioned at the center. At the time when the sample reached 750 ° C, oxygen gas was introduced into the apparatus 1 at a flow rate of 300 sccm and a pressure of approximately 0.7 Pa, and the surface was oxidized for 5 minutes. In addition, 7 in FIG. 4 has shown the evaporation source for AIP at the time of forming an intermediate | middle layer by AIP method.

Next, a sputtering cathode 6 equipped with two aluminum targets was sputtered by applying pulsed DC power of about 2.5 kW in an atmosphere of argon and oxygen, and the temperature condition (750 ° C.) almost equal to the oxidation temperature. Aluminum oxide (alumina) was formed at. In forming alumina, the discharge state was maintained in what is called a transition mode using discharge voltage control and plasma emission spectroscopy, and the alumina film of about 2 micrometers was formed. In addition, in these film formation, the rotating table 3 shown in FIG. 4 was rotated (idle), and the base holder (oil-based rotation jig) 4 provided on it was also rotated.

Each sample after the completion of the treatment was analyzed by thin film X-ray diffraction to identify the crystal structure. The results are shown in Table 4 below. When the films were formed under conditions satisfying the requirements specified in the present invention (Nos. 1 to 8), they had a good crystal structure (that is, a structure mainly composed of an α-type crystal structure). It can be seen that an alumina film is formed.

No. Mezzanine Crystal tissue One Cr metal film (0.1㎛) α 2 Ti metal film (0.1㎛) α 3 TiAl alloy film (0.1㎛) α + trace γ 4 Fe-based metal film α + trace γ 5 CrN _0.31 α 6 CrN _0.59 α 7 CrN _0.75 α 8 CrN _0.85 α + trace γ 9 CrN _0.96 α + γ

(3) Example concerning a 3rd aspect

As a base material for forming the alumina film, alumina film was formed on the substrate in a PVD device (vacuum film forming device) shown in FIG. 14 using a commercially available cBN sintered body cutting tool. First, the sample (substrate) 2 is set in the substrate holder (oily rotating jig) 4 in the apparatus 1, and the inside of the apparatus 1 is evacuated until it becomes almost vacuum, and then the side surface inside the apparatus. The sample was heated to 750 degreeC with the heater 5 arrange | positioned at the center. When the sample reached 750 ° C, oxygen gas was introduced into the apparatus 1 at a flow rate of 300 sccm and a pressure of approximately 0.7 Pa, and the surface was oxidized for 20 minutes.

Next, a sputtering cathode 6 equipped with two aluminum targets is sputtered by applying a pulsed DC power of about 2.5 kW in a mixed atmosphere of argon and oxygen, and the temperature condition is almost the same as the oxidation temperature (750 ° C.). ), An alumina film was formed. In the formation of the alumina film, the discharge state was maintained in a so-called transition mode using discharge voltage control and plasma emission spectroscopy to form an alumina film having a thickness of about 2 μm. In addition, in the formation of this alumina film, the rotary table 3 shown in FIG. 14 was rotated (idle), and the substrate holder (oil-based rotation jig) 4 provided thereon was also rotated.

About the sample of each Example after completion of a process, it analyzed by thin film X-ray diffraction and specified the crystal structure. 15 is a graph showing thin film X-ray diffraction results of an alumina film formed on a cBN sintered body substrate. In Fig. 15, many diffraction peaks were observed, including the diffraction peaks from the cBN sintered body of the substrate. First, the diffraction peaks from the film and the diffraction peaks from the substrate were discriminated in contrast with the result of X-ray diffraction with the substrate alone. It was. In Fig. 15, a triangular mark is attached to the diffraction peaks from the substrate, and among these, the diffraction peaks by cBN are marked with "▼" and the diffraction peaks other than cBN are labeled with "i". In addition, the original mark was attached to the diffraction peak from a film, and among these, the diffraction peak from the alumina of an alpha-type crystal structure was attached with "(circle)", and the other peak was attached with "(circle)".

As can be seen from Fig. 15, although the cBN sintered body based on the substrate has many diffraction peaks in addition to cBN, it is a diffraction peak from the bonded phase. Since some of the diffraction peaks considered to be the bonded phases were observed at an angle coinciding with the hexagonal AlN, the bonded phases are considered to include at least AlN. As can be seen from Fig. 15, most of the diffraction peaks from the coating are from α-alumina, and very few peaks were observed at the positions corresponding to the diffraction from? -Armina.

In addition, in the result of compositional analysis by XPS (X-ray photoelectron spectroscopy), the film contained a small amount (about 1 atomic%) of Ar, except that the film composition contained Al: 0 in a ratio of 2: 3. It is.

From these results, the film formed on the cBN sintered body substrate can be specified as an alumina film mainly composed of the α-type crystal structure, and a coating member coated with an alumina film mainly composed of the α-type crystal structure on the cBN sintered body substrate is produced. I could judge that I could.

The coating member thus produced is mainly formed on the cBN sintered body substrate having excellent hardness, and mainly formed of an alumina film having excellent oxidation resistance, and an α-type crystal structure having good thermal stability. When applied, it is suitable for applications such as cutting high hardness materials at high speed, and excellent performance can be expected.

(4) Example according to the fourth aspect

<First Embodiment>

The TiAlN film having a film thickness of 2 to 3 µm was formed on the substrate made of 12.7 mm x 12.7 mm x 5 mm, the surface of which was mirror-polished (about Ra = 0.02 µm), as a base coating by AIP method in advance. Ready. The film composition of TiAlN is Ti _0.55 Al _0.45 N.

As a comparative example, the surface of the said TiAlN film or CrN film was oxidized and the alumina film was formed. The oxidation treatment and the formation of the alumina coating were performed by the vacuum film forming apparatus shown in Fig. 5 (AIP-S40 composite machine manufactured by Shinsei Steel Co., Ltd.).

Specifically, the oxidation treatment was performed as follows. That is, after setting the sample (substrate) 2 to the substrate holder (oil-based rotation jig) 4 on the rotary table 3 in the chamber 1, the chamber 1 is evacuated until it becomes almost vacuum. The sample 2 was heated until it became 750 degreeC (substrate temperature in an oxidation process) with the heater 5 installed in two places and the center part of the side inside the chamber 1. When the temperature of the sample 2 became predetermined temperature, oxygen gas was introduce | transduced into the chamber 1 so that the flow volume might be 300 sccm and the pressure 0.75 Pa, and it heated and maintained for 20 minutes, and was oxidized.

In addition, the base film formation, oxidation treatment, and alumina film formation to be described later rotate the rotating table 3 in Fig. 5 while rotating the substrate 3 (base rotor jig) 4 provided thereon. ) Was also performed while rotating (rotating).

Next, an alumina film was formed on the base film after oxidation treatment. The formation of the alumina film is carried out in a sputtering cathode 6 equipped with two aluminum targets in FIG. 5 with the substrate temperature at approximately the same temperature (750 ° C) as that of the oxidation treatment step in an argon and oxygen atmosphere. A pulsed DC power of 2.5 kW was applied and the reactive sputtering method was adopted. The alumina film was formed by controlling the discharge voltage and the argon-oxygen flow rate ratio by using plasma emission spectroscopy, and making the discharge state the so-called transition mode. In this way, an alumina film having a film thickness of about 2 μm was formed.

In addition, as an example of this invention, the experiment was performed similarly to the said comparative example except having performed the following gas ion bombard process before an oxidation process. That is, after performing a gas ion bombard process on the surface of the said TiAlN film or CrN film, it oxidized and formed the alumina film.

The gas ion bombard treatment was performed as follows. After setting the sample (substrate) 2 to the substrate holder (oil-based rotation jig) 4 on the rotary table 3 in the chamber 1, and evacuating the chamber 1 until it becomes almost vacuum, the chamber (1) The sample was heated until it became 550 degreeC with the heater 5 installed in two internal side surfaces and the center part. When the temperature of the sample became a predetermined temperature, Ar gas was introduced into the chamber 1 at a pressure of O.75 Pa, and the filament 15 for hot electron emission was extended in a wire perpendicular to the surface of Fig. 5. ), The Ar electrons were emitted and the Ar gas in the vicinity of the filament 15 was converted into plasma to generate an Ar plasma.

The gas ion bombard treatment was performed by applying a bias voltage 14 to the substrate in the Ar plasma for 5 minutes at -300V for 10 minutes at -400V, followed by 10 minutes at -400V. Was performed. Moreover, also in this case, the process was performed, rotating the rotating table 3 and the base material holder (the planetary rotation jig) 4.

Next, after heating the base material to 750 degreeC with the heater 5, it oxidized and formed the alumina film similarly to the said comparative example, and formed the alumina film whose film thickness is about 2 micrometers.

Although not carried out in this embodiment, as shown in Fig. 5, an AIP evaporation source (arc evaporation source) 7 is provided to form the base film by performing the gas ion bombard treatment, the oxidation treatment and the alumina film formation. You may carry out in the apparatus 1.

The surface of the alumina film thus obtained was analyzed by a thin film X-ray diffraction apparatus to identify the crystal structure of the alumina film. The result is shown in FIG. 16 (comparative example) and FIG. 17 (example of this invention).

From Fig. 16, the main peaks of X-ray diffraction are diffraction peaks (hereinafter referred to as &quot; α alumina peaks &quot;) representing alumina of the α-type crystal structure, and other diffraction peaks and Ti-type crystal structures indicating TiAlN of the base film Some diffraction peaks (hereinafter referred to as "γ alumina peaks") that represent alumina can also be seen. From this, when alumina film is formed by the conventional method, it turns out that the film which mixed the alumina of an alpha type crystal structure and the alumina of a gamma type crystal structure is formed.

On the other hand, in FIG. 17 showing the result of the example of the present invention, the production of alumina of the γ-type crystal structure is suppressed to a level at which the γ-alumina peak can be barely confirmed, and the ratio of the alumina of the α-type crystal structure is increased by that much. It is obvious.

Moreover, the result of having observed the surface of these alumina films by SEM (magnification: 10,000 time) is shown in FIG. 18 (a) is an SEM observation photograph showing the alumina film surface in a comparative example, and FIG. 18 (b) is an SEM observation photograph showing the alumina film surface in the example of this invention.

From Fig. 18A, the alumina film in the comparative example is divided into crystal grains (white portions) and flat portions (black portions) in which the grains do not grow, and the grown grains remain coarse while being coarse. It can be seen that. On the other hand, the alumina film of the example of this invention shown to FIG. 18 (b) is comprised from uniform and fine crystal grain, and clearly differs from the film surface of the said comparative example.

Second Embodiment

Except for forming a CrN film as the base film, experiments were carried out in the same manner as in the first embodiment, and the surface of the obtained alumina film was analyzed by a thin film X-ray diffraction apparatus to identify the crystal structure of the film. The result is shown in FIG. 19 (comparative example) and FIG. 20 (example of this invention).

19 and 20, both of the diffraction peaks determined by alumina show the α-type crystal structure, and both of the examples of the present invention and the comparative examples can obtain an alumina film composed almost exclusively of the α-type crystal structure. In the thin film X-ray diffraction analysis, no significant difference is observed between the alumina films of the present invention and the comparative example. However, when the heights of the diffraction peaks of Figs. 19 and 20 are compared, it can be seen that the diffraction intensity in Fig. 20 is slightly smaller than that of Fig. 19. This may be considered to be due to the influence of the refinement of the crystal grains described later.

In addition, the surface of these alumina films was observed by SEM similarly to the said 1st Example. The result is shown in FIG. 21 (a) is an SEM observation photograph showing the alumina film surface in a comparative example, and FIG. 21 (b) is an SEM observation photograph showing the alumina film surface in the example of this invention.

As shown in Fig. 21 (b), the alumina film of the present invention is composed of finer grains, and the porosity between the grains is very small compared to the alumina film of the comparative example (Fig. 21 (a)), and the grain size is increased. You can see that it is progressing. Although no remarkable difference was observed in the thin film X-ray diffraction image, the SEM observation showed that the difference in the surface state was remarkable as described above, and the alumina film of the example of the present invention is considered to exhibit more excellent characteristics.

The gas ion spring is also used when an alumina film is formed under the same conditions as those of the first and second embodiments using a high-speed steel substrate and a cBN sintered body as a base material without forming a base film such as a CrN film or a TiAlN film. When the oxidation treatment was carried out after the bard treatment, it was confirmed that the crystal structure of the alumina formed had a small γ-type crystal structure, which was mainly the α-type crystal structure, and formed a fine and uniform alumina film with crystal grains.

(5) Example concerning a fifth aspect

<First Embodiment>

Using the description of the following ① to ③, a metal ion bombard treatment, an oxidation treatment, and an alumina coating were sequentially performed in the vacuum film forming apparatus (AIP-S40 composite machine manufactured by Shinsei Co., Ltd.) shown in FIG. 7.

<Kind of mention>

① Carbide substrate (12mm × 12mm × 5mm)

② Si wafer (silicon wafer) (20mm square)

③ On a carbide substrate (12 mm x 12 mm x 5 mm),

A TiAlN film having a film thickness of about 2 μm by the AIP method

First, the metal ion bombard treatment was performed as follows. That is, the sample (substrate) 2 is set in the base holder (oil-based rotation jig) 4 on the rotary table 3 in the chamber 1, and the chamber 1 is evacuated to vacuum, and then the chamber 1 The sample was heated until it became 600 degreeC with the heater 5 installed in two inside side surfaces and center part, and it hold | maintained at that temperature for 30 minutes.

Thereafter, the power of the heating heater is raised to a level at which the substrate temperature can be maintained at 750 ° C in a steady state, and then an arc current of 80 A is flowed to the evaporation source 7 for AIP with a Cr target to produce plasma containing Cr ions. In this state, a bias voltage of direct current is applied to the substrate by the bias power supply 14 through the turntable 3 and the substrate holder (planetary rotation jig) 4, and Cr ions are irradiated to the substrate to cause metal ions. Bombard treatment was performed. The bias voltage was applied for 9 minutes at −600 V for 2 minutes, −700 V for 2 minutes, and −800 V for 5 minutes. In addition, the substrate temperature at the end of the metal ion bombard treatment was about 760 ° C.

The metal ion bombard treatment, the oxidation treatment to be described later, and the formation of the alumina coating are performed by rotating (rotating) the rotary table 3 in FIG. 7, and at the same time, a substrate holder (oily rotating jig) provided thereon ( 4) was also performed while rotating (rotating).

After the metal ion bombard treatment, the arc discharge and the application of the bias voltage were stopped to perform the oxidation treatment. Oxidation treatment was performed by introducing oxygen gas into the chamber 1 after the metal ion bombard treatment at a flow rate of 300 sccm and a pressure of O.75 Pa, followed by heating and holding for 30 minutes. In this step, the substrate temperature at the end of the oxidation treatment was 750 ° C.

An alumina film was formed on the surface of the oxidation treatment. The formation of the alumina film is about 2.5 to the sputtering cathode 6 equipped with two aluminum targets in FIG. The pulsed DC power of kW was applied, and the reactive sputtering method was adopted. The formation of the alumina coating was performed by controlling the discharge voltage and the argon-oxygen flow rate ratio by using plasma emission spectroscopy, and making the discharge state the so-called transition mode. In this way, an alumina film having a film thickness of about 2 μm was formed (Nos. 1 to 3 in Table 5 described later).

Second Embodiment

During the metal ion bombard treatment, nitrogen ion is introduced into the chamber 1 so as to have a partial pressure of 0.05 Pa, and the metal ion bombard treatment is carried out in the same manner as in the first embodiment except that the metal ion bombard treatment is performed under a nitrogen atmosphere, Oxidation treatment and alumina coating were performed (Nos. 4 to 6 in Table 5 described later).

Third Embodiment

A metal ion bombardment treatment, an oxidation treatment, and an alumina coating were carried out in the same manner as in the first embodiment, except that the target material adhering to the evaporation source for AIP as a source of metal ions in the metal ion bombard treatment was Ti instead of Cr. Was formed (Nos. 7 to 9 in Table 5 below).

Comparative Example

The alumina film was formed after the oxidation treatment without performing the metal ion bombard treatment. In addition, as a conventional method, after the oxidation treatment of further forming a CrN film on the TiAlN film of the substrate 3 described above, a method of forming an alumina film was also performed. The oxidation treatment and the formation of the alumina coating were performed in the same manner as in the first embodiment.

<Thin X-ray diffraction analysis of the obtained alumina film>

The surface of the alumina film formed by the method of the said 1st-3rd Example and a comparative example was analyzed with the thin film X-ray diffraction apparatus, and the crystal structure of the alumina film was identified. The results are shown in Table 5.

No. Substrate (+ Thin Film) Metal Ion Bombard Crystal Structure of Alumina Film One Example 1 Carbide Cr α 2 Si wafer α 3 Carbide + TiAlN α 4 Example 2 Carbide Introduction of Cr + N ₂ α 5 Si wafer α 6 Carbide + TiAlN α 7 Example 3 Carbide Ti α + trace γ 8 Si wafer α + trace γ 9 Carbide + TiAlN α + trace γ 10 Comparative example Carbide none α + γ 11 Si wafer γ 12 Carbide + TiAlN α + γ 13 Carbide + TiAlN + CrN α

From Table 5, in Nos. 1 to 9 showing the results of the first to third embodiments, the TiAlN film having a film thickness of about 2 μm was formed on the cemented carbide, the Si wafer, and the cemented carbide substrate by the AIP method. In either case, it can be seen that the alumina film of the α-type crystal structure main body is formed. In comparison with the results of Nos. 1 to 6 and Nos. 7 to 9, in this embodiment, when Cr is used for the metal ion bombard treatment rather than Ti, an alumina film composed almost of α-type crystal structure can be formed. I can see that there is.

On the other hand, in the comparative example, when the TiAlN film and the CrN film were formed on the cemented carbide (No. 13), an alumina film formed almost exclusively of the α-type crystal structure could be formed. No. 10) or in the case where only the TiAlN film was formed on the cemented carbide (No. 12), an alumina film obtained by mixing the α-type crystal structure and the γ-type crystal structure was obtained. In addition, when a Si wafer was used as the substrate (No. 11), an alumina having an α-type crystal structure was not formed, and an alumina film composed almost of only the γ-type crystal structure was obtained.

From these results, it turns out that according to the method of the present invention, the alumina film of the α-type crystal structure main body can be formed without being limited to the type of the substrate.

(6) Example concerning a sixth aspect

The alumina film of this invention was formed using the PVD apparatus (vacuum film-forming apparatus) shown in the said FIG. First, the test piece in which the CrN film (base film) was formed in advance on the cemented carbide substrate by the AIP method is set in the substrate holder (oily rotating jig) 4 in the apparatus 1, and the apparatus 1 is almost vacuum. After evacuating until it became a state, the sample was heated to 750 degreeC with the heater 5 arrange | positioned at the side and center inside the apparatus. When the test piece became 750 degreeC, oxygen gas was introduce | transduced into the apparatus 1 at the flow volume of 300 sccm, and the pressure of about 0.7 Pa, and the surface was oxidized for 20 minutes. In addition, 7 in FIG. 4 has shown the AIP evaporation source at the time of forming a base film by AIP method.

Next, a sputtering cathode 6 equipped with two aluminum targets was sputtered by applying pulsed DC power of about 2.5 kW in an atmosphere of argon and oxygen, and the temperature condition (750 ° C.) almost equal to the oxidation temperature. , Aluminum oxide (alumina) was formed. In forming alumina, the discharge state was maintained in what is called a transition mode using discharge voltage control and plasma emission spectroscopy, and the alumina film of about 2 micrometers was formed. In addition, in these film formation, the rotating table 3 shown in FIG. 4 was rotated (idle), and the base holder (oil-based rotation jig) 4 provided on it was also rotated.

The alumina film after film-forming process analyzed crystallinity by thin film X-ray diffraction, and specified the crystal structure of an alumina film. As a result, it was confirmed from the alumina film that only a diffraction peak representing alumina having an α crystal structure can be observed.

The result of having observed the said alumina film with a transmission electron microscope (TEM) is shown in FIG. 22 (drawing surrogate photo) (magnification: 20000x). According to this TEM image and simultaneous EDX analysis (energy dispersive X-ray analysis), this film was formed from an area close to the substrate in order by the oxidation treatment process on the surface of the CrN film and CrN: chromium oxide having a thickness of 30 to 40 nm. It turned out that it has a three-layer structure of a (Cr ₂ 0 ₃ ) layer and an alumina layer. In addition, the alumina and chromium oxide layers were analyzed by electron beam diffraction. As a result, it was confirmed that all had corundum structures and were α-A ₂ O ₃ and α-Cr ₂ O ₃ , respectively.

FIG. 23 (drawing substitute photograph) is an enlarged view of a portion of FIG. 22. As is apparent from FIG. 23, it can be seen that as the film growth progresses and the film thickness increases, the crystal grains become large, and in the vicinity of the surface, the crystal has a maximum width of 0.5 µm and a length of columnar crystals of 1.5 µm. On the other hand, it can be seen that at the initial stage of the growth of the film, the size is about 0.3 μm at maximum.

As described above, although it is a general tendency that fine grains are formed at the beginning of the growth of the film and the grains grow with the growth of the film, the film cross-sectional observation of the alumina film formed by the PVD method so far (Surf. Coat. Technol., 94-95 (1997) p. 303-308, Surf. Coat. Technol., 142-144 (2001) p. 260-264, J. Vac. Sci. Technol. A20 (6), Nov / Dec (2002) p.2134-2136) Even in the sample capable of forming α-alumina, it was observed that a fine γ-alumina layer of crystal grains was formed at the initial stage of film formation, and the α-type crystal was reported to grow therein. It is becoming. From these things, it was thought that, when the α alumina film was formed by the PVD method, the inclusion of γ alumina was inevitable in the crystal fine region at the beginning of the film growth.

However, in the alumina film formed in the above order, the alumina film near the interface with α-Cr ₂ 0 ₃ was analyzed by electron beam diffraction at the time of TEM observation. As a result, diffraction results from α alumina were obtained in all regions. , γ-armina was found not to be detected. From this, it was found that by forming the alumina film under appropriate conditions including the type of the base film, alpha alumina can be formed even in a region where the crystal in the initial stage of the film growth is fine.

In addition, in this film, since the film thickness increases from the beginning of the film growth in which the crystal has a fine structure, the crystal grains grow in a columnar shape, but only α-alumina was observed in the electron beam diffraction in any crystal growth. will be.

In the above embodiment, the α-alumina of the present invention is obtained by oxidizing the surface layer of CrN formed as the base coating to a substrate temperature of 750 ° C. and subsequently forming an alumina coating on the base coating. As a result of studying the optimum conditions for forming the alumina film which consists only of a crystal structure, it turned out that (alpha) alumina can be formed also by the following manufacturing conditions.

That is, prior to the oxidation treatment of the base coating, the surface of the base coating is subjected to an ion bombard treatment with Ar ions or the like, or by the corundum structure oxide powder (preferably alumina powder). When the "damage treatment" was carried out, it was confirmed that the same α-alumina film could be formed even by performing oxidation treatment on the surface of the substrate at about 700 ° C.

From these, the α-alumina coating of the present invention is the base temperature at the time of oxidation treatment and film formation when the base coating is manufactured by combining CrN as the above pretreatment (ion bombard treatment or damage treatment by oxide powder). Is treated at 700 ° C. or higher, and pretreatment is not carried out, the substrate temperature at the time of oxidation treatment and film formation is treated at 750 ° C. or higher, whereby alumina having an α-type crystal structure is formed by alumina coating by PVD. It can be seen that a film can be formed.

In the case of performing the ion bombardment treatment, in the apparatus configuration shown in FIG. 4, a hot electron emission application filament for forming a gas ion plasma or a metal ion plasma is disposed in the apparatus (not shown), What is necessary is just to set it as the apparatus structure which can provide the power supply which can apply a bias voltage to a base material, and can perform ion bombard processing by applying the bias voltage of an appropriate value (for example, -400V or more).

(7) Embodiment of a film forming apparatus

The experimental example which formed the high heat-resistant (alpha) alumina film using the physical vapor deposition apparatus shown in FIG. 8 (but the arc source 7 was not provided) is given below.

As a sample to be used for the film forming experiment, a hard film (TiAlN) was formed in a thickness of 2 to 3 μm by arc ion fritting on a 12.7 mm square mirror surface (about Ra = 0.02 μm) and a 5 mm thick plate-shaped carbide substrate. One was used. At this time, the coating composition of TiAlN was TiO.55AlO.45N.

After setting this sample to the base holder (oily rotary jig) 4 on the rotary table 3, and evacuating it through the exhaust gas piping 11 by vacuum, the substrate temperature is radiated with the radiant heating heaters 51 and 52. After heating and raising to 550 degreeC, argon gas was introduce | transduced from the gas introduction tube 11 at the pressure of 2.7 Pa, and 15 A discharge was produced between the chamber and the thermoelectron emission filament which is the plasma source 8, and argon A plasma was generated. While irradiating the argon plasma, the substrate was subjected to ion bombardment treatment for 15 minutes at a DC voltage pulsed at a frequency of 30 kHz for 5 minutes at -300V, for 10 minutes at -400V.

Subsequently, the substrate heater is heated to 750 ° C. in the heaters 51 and 52, and when the sample is heated to the same temperature, oxygen gas is flown from the gas introduction tube 11 into the chamber at a flow rate of 300 sccm and a pressure of approximately O.75 Pa. The surface was thermally oxidized for 20 minutes.

Then, using a sputtering cathode equipped with two aluminum targets as the sputtering evaporation source 6, sputtering was performed by applying electric power of pulse DC sputtering of about 2.5 kW in an argon and oxygen atmosphere, which was approximately equal to the oxidation temperature. Under temperature conditions (750 ° C), aluminum oxide (alumina) was formed on the surface of the hard film. In the formation of the alumina film by this reaction sputtering method, the discharge state is maintained in what is called a transition mode using discharge voltage control and plasma emission spectroscopy, and about 2 micrometers of alumina films are formed.

The sample of the present Example after the completion of the treatment was analyzed by thin film X-ray diffraction to identify the crystal structure. 24 shows the thin film X-ray diffraction results of the alumina film formed on the TiAlN film. In this figure, the circle represents α-alumina (alumina mainly composed of α-type crystal structure), the white reverse triangle represents γ-alumina (alumina mainly composed of γ-type crystal structure), and the black reverse triangle represents peaks of TiAlN, respectively. have. As is apparent from FIG. 24, it can be seen that by using the apparatus of the present invention, an alumina film (high heat resistant oxidizing film) mainly composed of an α-type crystal structure can be formed on a practical hard film such as TiAlN.

In contrast, in the apparatus lacking the requirements of the apparatus of the present invention, it was confirmed in the experiment that a satisfactory coating could not be formed.

First, in the case of lacking the plasma source, the film was formed without performing the ion bombardment treatment in the step. In this case, although the formation of the alumina film containing an alpha type crystal structure on TiAlN was possible, the mixing of the gamma type crystal structure was confirmed. Moreover, it became difficult to say that the alumina film with a uniform crystal grain is formed.

When a bias power supply capable of applying intermittent direct current voltage is lacking, that is, when a direct current bias power supply is used, an arc occurs. In addition, the high frequency bias power supply was not applicable to the planetary rotating table.

Regarding the substrate heating ability of the radiation type superheating mechanism, the α-type crystal could not be obtained when the substrate temperature was lower than 650 ° C. Also, when the substrate temperature exceeded 800 ° C, deterioration of the TiAlN film was recognized.

Supplementing with the embodiment of the present invention, the frequency of the intermittent application is preferably in the range of 10 kHz to 400 kHz for the bias power supply for applying a negative pulsed bias voltage to the substrate holder (the planetary rotary jig). At frequencies below 10 kHz, unstable phenomena due to the generation of arc discharges occur, and problems such as matching occur at high frequencies above 400 kHz. Therefore, it is recommended to set the above range.

In addition, formation of the alumina film by this apparatus is performed by the reactive sputtering method as mentioned above. That is, by operating the aluminum target attached to the sputtering evaporation source in a mixed atmosphere of argon and oxygen, metal aluminum is sputtered and compounded with oxygen on the substrate. In order to perform a film formation with a high film formation speed, it is necessary to keep the sputtering mode in a so-called transition mode. From this point of view, it is preferable that the sputtering power supply for driving the sputtering evaporation source can be subjected to constant voltage control. In addition, it is preferable that this apparatus is equipped with the spectrometer which monitors the plasma light emission of a sputtering evaporation power source, in order to grasp | ascertain the sputtering mode.

By employing the above-described configuration, the alumina film mainly composed of the α-type crystal structure main body having excellent heat resistance can be formed at a relatively low temperature region without deteriorating the characteristics of the substrate and the hard film without using a high temperature such as the CVD method. In addition, since there is no need to form an intermediate film between the hard film and the alumina film of the α-type crystal structure as in the related art, the laminated film can be efficiently formed, while the degradation of cutting performance due to the intermediate film does not occur. .

Therefore, by realizing the laminated | multilayer film which consists of such an alumina film | membrane which mainly consists of such an alpha-type crystal structure, and these manufacturing methods, the cutting tool etc. which are more excellent in abrasion resistance and heat resistance than before can be provided at low cost.

The present invention is also practical in that it provides a method for forming alumina having an α-type crystal structure having excellent oxidation resistance at a relatively low temperature on a titanium-based hard film such as TiN, TiCN, TiC, or the like.

In addition, when the gas ion bombard treatment is performed, an alumina film that can be expected to have more excellent wear resistance and heat resistance, in particular, fine and uniform crystal grains can be formed, and when the metal ion bombard treatment is performed, Regardless of the type of base coating, an alumina coating can be formed on the substrate or the base coating. In this invention, the alumina film can be formed also on a cBN sintered compact, without specifying the composition.

Claims (66)

It is a method of forming the alumina film which mainly has an alpha type crystal structure on the base material in which the base film was formed previously, After forming a hard film composed of a metal component such as Al and Ti and a compound such as B, C, N, O as the base film, the hard film is oxidized to form an oxide-containing layer, and then the oxide A method of producing an alumina film mainly comprising an α-type crystal structure, wherein an alumina film mainly comprising an α-type crystal structure is formed on the containing layer. The production method according to claim 1, wherein the oxide-containing layer is substantially composed of alumina at the most surface side. The manufacturing method according to claim 1, wherein the base film is made of TiAlN. The nitride, carbide and carbonaceous material as claimed in claim 1, wherein the base film is made of Al and Ti and at least one element selected from the group consisting of Group IVa (excluding Ti), Group Va, Group VIa and Si. A process for producing a cargo, boride, nitrate or carbonitride. The manufacturing method according to claim 1, wherein the base film is made of TiAlCrN. It is a method of forming the alumina film which mainly has an alpha type crystal structure on the base material in which the base film was formed previously, As the base film, after forming a hard film made of a metal component containing Al and a compound of B, C, N, O and the like, the hard film is oxidized to form an oxide containing layer, and then the oxide A method of producing an alumina film mainly comprising an α-type crystal structure, wherein an alumina film mainly comprising an α-type crystal structure is formed on the containing layer. The nitride film, carbide, carbonitride, boride and nitride of claim 6, wherein the base film is made of Al and at least one element selected from the group consisting of Groups IVa, Va, VIa, and Si. Or a production method comprising carbon dioxide. It is a method of forming the alumina film which mainly has an alpha type crystal structure on the base material in which the base film was formed previously, As the base film, after forming a hard film made of a metal having a standard free energy of oxide generation greater than aluminum and a compound of B, C, N, 0, etc., the hard film is oxidized to form an oxide containing layer. Thereafter, an alumina film mainly composed of the α-type crystal structure is formed on the oxide-containing layer. The production method according to claim 8, wherein as the base film, a hard film made of a compound of Ti and B, C, N, 0, and the like, wherein the standard free energy of oxide formation is a metal larger than aluminum. The manufacturing method according to claim 8, wherein as the base film, one or two or more layers of laminations selected from the group consisting of TiN, TiC, and TiCN are formed. The manufacturing method of Claim 8 which forms the composition gradient layer of the both material structural elements joined by the joining interface between the said hard film and a base material or a hard film. The production method according to claim 8, wherein after the titanium oxide containing layer is formed as the oxide-containing layer, in forming alumina, an alumina film is formed with reduction of the titanium oxide on the surface of the layer. The method according to claim 8, wherein after the Ti0 ₂ containing layer is formed as the oxide-containing layer, in forming alumina, the alumina film is formed with reduction of Ti0 ₂ to Ti ₃ 0 _{5 on} the surface of the layer. It is a method of manufacturing the alumina film which mainly has an alpha-type crystal structure on the base material (including the base film previously formed on the base material), Before forming the alumina, at least any one of the following films (a) to (c) is formed, and then the surface is oxidized and an alumina film is formed thereafter. Method of preparation. (a) Coatings made of pure metals or alloys (b) coatings of metallic subjects that dissolve nitrogen, oxygen, carbon or boron; (c) coatings of metal nitrides, oxides, carbides or borides containing insufficient nitrogen, oxygen, carbon or boron for stoichiometric composition; The manufacturing method of Claim 1, 6, 8, or 14 which performs the said oxidation process, maintaining substrate temperature at 65O-800 degreeC in oxidizing gas containing atmosphere. The manufacturing method of Claim 1, 6, 8, or 14 which performs formation of the alumina film which mainly uses the said alpha type crystal structure by PVD method. The process of oxidizing the surface of the said base film, and the process of forming an alumina film mainly as said (alpha) type crystal structure are performed in the same apparatus of Claim 1, 6, 8 or 14. Manufacturing method. The alumina film according to claim 1, 6, 8, or 14, wherein the base film is formed, the surface of the base film is oxidized, and the α-type crystal structure is mainly used. The manufacturing method which performs a process to form sequentially in the same apparatus. The coating member excellent in abrasion resistance and heat resistance characterized by having an alumina film mainly composed of an α-type crystal structure produced by the production method according to claim 1, 6, 8 or 14. In the laminated film which has a hard film which consists of a compound of B, C, N, O, etc. with the metal component which Al and Ti are essential, A laminated film having excellent abrasion resistance and heat resistance, comprising an oxide-containing layer formed by oxidizing the hard film and an alumina film mainly composed of an α-type crystal structure formed on the oxide-containing layer. The laminated film according to claim 20, wherein the oxide-containing layer is substantially made of alumina at the most surface side. The laminated film according to claim 20, wherein the hard film is made of TiAlN. 21. The hard film according to claim 20, wherein the hard film is nitride, carbide, carbonaceous containing Al and Ti and at least one element selected from the group consisting of Group IVa (excluding Ti), Group Va, Group VIa, and Si. A laminated film composed of a cargo, boride, nitrate or carbonitride. The laminated film according to claim 20, wherein the hard film is made of TiAlCrN. In the laminated film which has a hard film which consists of metal components which make Al essential, and compounds, such as B, C, N, O, Lamination | stacking excellent in wear resistance and heat resistance characterized by having the oxide-containing layer which consists of an alumina substantially the most surface side formed by oxidizing the said hard film, and the alumina film which mainly has an alpha type crystal structure formed on the said oxide containing layer. film. The nitride, carbide, carbonitride, boride and nitride oxide of claim 25, wherein the hard coating is an essential component of Al and at least one element selected from the group consisting of Groups IVa, Va, VIa, and Si. Or a laminated film made of carbonitride. The laminated film according to claim 20 or 25, wherein the alumina film formed on the oxide-containing layer has an α-type crystal structure of 70% or more. The laminated film coating tool of Claim 20 or 25 is formed in the surface. A step of forming at least one of the following films (a) to (c) as an intermediate layer on the substrate, a step of oxidizing the surface of the intermediate layer, and subsequently forming an alumina film mainly composed of an α-type crystal structure. A method for producing a member coated with an alumina film of an α-type crystal structure principal, which is sequentially performed in the same film forming apparatus. (a) Coatings made of pure metals or alloys (b) coatings of metallic subjects with nitrogen, oxygen, carbon or boron (c) coatings of metal nitrides, oxides, carbides or borides containing insufficient nitrogen, oxygen, carbon or boron for stoichiometric composition; A step of forming a base film on a substrate, a step of forming at least one of the following films (a) to (c) as an intermediate layer on the surface of the base film, and a step of oxidizing the surface of the intermediate layer, followed by α-type A method of producing a member coated with an alumina film of an α-type crystal structure principal, which is performed sequentially in the same film forming apparatus, in which a step of forming an alumina film mainly composed of a crystal structure is performed. (a) Coatings made of pure metals or alloys (b) coatings of metallic subjects with nitrogen, oxygen, carbon or boron (c) A coating consisting of metal nitrides, oxides, carbides or nitrides containing nitrogen, oxygen, carbon or boron insufficient for stoichiometric composition. On the cBN sintered body base material which consists of a bonding phase and a cubic boron nitride dispersion phase, it is a method of manufacturing the alumina film which mainly consists of alpha type crystals, The cBN sintered compact base material is oxidized, and an alumina film is formed after that, The manufacturing method of the alumina film of (alpha) -type crystal structure main body. 32. The method of claim 31, wherein said bonding phase comprises at least one member selected from the group consisting of TiC, TiN, TiCN, AlN, TiB ₂ and Al ₂ O ₃ . 32. The production method according to claim 31, wherein the oxidation treatment is carried out under an oxidizing gas-containing atmosphere at a substrate temperature of 650 to 800 占 폚. The manufacturing method of Claim 31 which forms the alumina film which mainly uses the said alpha type crystal structure by applying a physical vapor deposition method at 650-800 degreeC of base materials. In the coating member which coat | covered the alumina film which mainly consists of (alpha) type crystals on the cBN sintered compact which consists of a bonding phase and a cubic boron nitride dispersion phase, A member coated with an alumina film of an α-type crystal structure main body, wherein an oxide-containing layer is interposed between the cBN sintered body substrate and the alumina film. 36. The member of claim 35, wherein said bonding phase comprises at least one member selected from the group consisting of TiC, TiN, TiCN, AlN, TiB ₂ and Al ₂ O ₃ . 36. The member of claim 35, wherein the bonding phase comprises 1-50% by volume based on the entire sintered body. 36. The member according to claim 35, wherein the alumina film mainly composed of the α-type crystal structure has a compressive residual stress. In the method of manufacturing the coating member which coat | covered the alumina film which mainly consists of (alpha) type crystals on the cBN sintered compact which consists of a bonding phase and a cubic boron nitride dispersion phase, An alumina film mainly containing an α-type crystal structure, characterized in that a step of oxidizing the surface of the cBN sintered body and a step of forming an alumina film mainly having an α-type crystal structure are performed in the same film forming apparatus. Method for producing a coated member. (Including the base film formed on the base material in advance. The same applies below.) A method of forming an alumina film mainly composed of the α-type crystal structure on the base material, The surface of a base material is subjected to a gas ion bombard treatment, and then the surface is oxidized, and then an alumina film is formed. 41. The base film according to claim 40, wherein at least one element selected from the group consisting of Groups 4a, 5a, and 6a, Al, Si, Fe, Cu, and Y of the periodic table, and C, N, B, The manufacturing method which forms any 1 or more types of the compound with 1 or more types of O, or the mutual solid solution of these compounds. 41. The method of claim 40, wherein the base film is selected from the group consisting of Ti (C, N), Cr (C, N), TiAl (C, N), CrAl (C, N) and TiAlCr (C, N). The manufacturing method which forms 1 or more types which become. The manufacturing method of Claim 40 whose said base material is steel materials, a cemented carbide, a cermet, a cBN sintered compact, or a ceramic sintered compact. 41. The method of claim 40, wherein the gas ion bombard treatment is performed by applying a voltage to the substrate in a gas plasma in a vacuum chamber. Forming a base film on the substrate, performing a gas ion bombard treatment on the surface of the base film, oxidizing the surface, and subsequently forming an alumina film mainly composed of an α-type crystal structure, A method for producing a member coated with an alumina film of an α-type crystal structure principal, which is carried out sequentially in the same apparatus. 46. The method of claim 45, wherein the base film is selected from the group consisting of Ti (C, N), Cr (C, N), TiAl (C, N), CrAl (C, N) and TiAlCr (C, N). The manufacturing method which forms 1 or more types which become. (Including the base film formed on the base material in advance. The same applies below.) A method of forming an alumina film mainly composed of the α-type crystal structure on the base material, The surface of a base material is subjected to a metal ion bombard treatment, and then the surface is oxidized to form an alumina film thereafter. 48. The method of claim 47, wherein the metal ion bombard treatment is performed by generating a metal plasma while applying a voltage to the substrate in a vacuum chamber. 48. The method of claim 47, wherein the metal ion bombard treatment is performed by generating a plasma of Cr or Ti from a vacuum arc evaporation source while applying a voltage to the substrate in a vacuum chamber. 48. The production method according to claim 47, wherein the oxidation treatment is performed by maintaining the substrate temperature at 65O to 800 DEG C in an oxidizing gas-containing atmosphere. (Including the base film formed on the base material in advance. The same applies to the following.) A member having an alumina film mainly composed of the α-type crystal structure on the base material, In the vicinity of the substrate surface, a concentration gradient layer in which metal used for the metal ion bombard treatment is concentrated toward the surface layer side is formed, and an oxide-containing layer and an alumina film mainly composed of the α-type crystal structure main body are sequentially formed on the surface side of the concentration gradient layer. A member coated with an alumina film of an α-type crystal structure main body. A step of subjecting the surface of the substrate to a metal ion bombard treatment, a step of oxidizing the surface, and subsequently a step of forming an alumina film mainly composed of the α-type crystal structure, in the same apparatus, wherein A method for producing a member coated with an alumina film of a mold crystal structure main body. Forming a base film on the substrate, performing a metal ion bombard treatment on the surface of the base film, oxidizing the surface, and subsequently forming an alumina film mainly composed of an α-type crystal structure, A method for producing a member coated with an alumina film of an α-type crystal structure main body, which is performed sequentially in the same film forming apparatus. 55. The base film according to claim 53, wherein the base film is at least one element selected from the group consisting of Groups 4a, 5a, and 6a, Al, Si, Cu, and Y of the periodic table, and at least one of C, N, B, and O. The manufacturing method which is any 1 or more types of the compound with the above element, the mutual solid solution of these compounds, or the single body or compound which consists of 1 or more types of elements among C, N, and B. The manufacturing method of Claim 53 whose said base material is steel materials, a cemented carbide, a cermet, a cBN sintered compact, a ceramic sintered compact, a crystalline diamond, or a Si wafer. It is an alumina film formed by the physical vapor deposition method on the base material (including the base film previously formed on the base material), When the crystal structure of the alumina film was observed with a cross-sectional transmission electron microscope (magnification: 20000 times), at least the film growth initiation portion was composed of alumina crystals having a fine structure, and crystals other than the α-type crystal structure in the fine crystal region. An alumina film having an α-type crystal structure, wherein the structure is not substantially observed. The alumina film of Claim 56 whose alumina crystal of the said microstructure is 0.3 micrometer or less in the range from the beginning of growth to the thickness direction 0.5 micrometer. 57. The alumina film of claim 56, wherein substantially no crystal structure other than the α-type crystal structure is observed throughout the alumina film. The alumina film of Claim 56 which the alumina of an alpha type crystal structure grew to the columnar shape at the film surface side. The alumina film of Claim 56 whose film thickness of an alumina film is 0.5-2 micrometers. A vacuum chamber, a substrate holder rotatably disposed in the vacuum chamber to hold a plurality of substrates, an inert gas and an oxidizing gas introduction mechanism into the vacuum chamber, a plasma source disposed at a position opposite to the substrate holder; And a sputtering evaporation source disposed at a position opposite the substrate holder, a radiant heating mechanism disposed at a position opposite the substrate holder and capable of heating the substrate, and a negative pulse bias connected to the substrate holder and connected to the substrate holder. Physical vapor deposition apparatus comprising a bias power supply capable of applying a voltage. 62. The physical vapor deposition apparatus according to claim 61, wherein an arc evaporation source is disposed at a position opposite to the substrate holder in place of or in addition to the plasma source. 62. The physical vapor deposition apparatus according to claim 61, wherein the radiant heating mechanism comprises a tubular heating source disposed concentrically with the rotational center of the substrate holder, and a planar heating source disposed on the side of the substrate holder. 63. The tubular heating source according to claim 61, wherein the cross-sectional shape of the vacuum chamber is any one of a rectangle, a hexagon, or an octagon, and the radiant heating mechanism is arranged concentrically with the rotation center of the substrate holder. And a pair of the sputtering evaporation source and the planar heating source disposed on opposite inner surfaces of the vacuum chamber. 62. A cylindrical heating source according to claim 61, wherein the cross-sectional shape of the vacuum chamber is hexagonal or octagonal, and the radiant heating mechanism is a cylindrical heating source disposed concentrically with the rotation center of the substrate holder, and a plane disposed on the side of the substrate holder. And a pair of the sputtering evaporation source, the planar heating source, and the arc evaporation source, disposed on opposite inner surfaces of the vacuum chamber. 62. The physical vapor deposition apparatus according to claim 61, wherein said plasma source is a filament for hot electron emission arranged in said vacuum chamber to be proximate said substrate holder in a longitudinal direction thereof.