JP2020157377A - Coated tool - Google Patents

Abstract

To obtain a coated tool which is coated with a nitride or a carbonitride of Al and Cr having excellent durability.SOLUTION: In a coated tool, a hard film is a nitride or a carbonitride which contains 50 atomic% or more of Al, 10 atomic% or more of Cr, and 90 atomic% or more of the total content of Al and Cr as an average content ratio to the total amount of metal elements including a semimetal, a peak intensity thereof due to an fcc structure in X-ray diffraction shows the maximum intensity, and is configured from a collection of columnar particles grown in a film thickness direction. A value of a hard film X-ray diffraction intensity ratio TC (311) is 1.30 or more, and an intermediate film, which contains a nitride or a carbonitride of Ti, is provided between a base material and the hard film.SELECTED DRAWING: Figure 1A

Description

The present invention is, for example, a tool used for cutting tools such as dies and inserts for press working and casting, and is hard including a nitride or carbonitride containing Al and Cr coated by a chemical vapor deposition method. The present invention relates to a covering tool having a coating on the surface of the tool.

Conventionally, in order to improve the life of a tool such as a mold or a cutting tool, a coated tool in which the surface of the tool is coated with a hard film by a physical vapor deposition method or a chemical vapor deposition method has been used. Among the tools, cutting tools are used in a usage environment with a large machining load. Among various hard films, the hard film made of Al and Ti nitrides or carbonitrides and the hard film made of Al and Cr nitrides or carbonitrides are film types with excellent wear resistance and heat resistance and are coated. Widely used for cutting tools and the like.

Looking at the hard coating used in coating tools, the formation of a hard coating consisting of Al and Ti nitrides or carbonitrides is carried out by physical vapor deposition and chemical vapor deposition on coated cutting tools actually sold on the market. The vapor deposition method is widely applied. On the other hand, for the formation of a hard film composed of Al and Cr nitrides or carbonitrides, the physical vapor deposition method is actually applied to the coated cutting tools sold on the market, and the chemical vapor deposition method is used. The current situation is that it has not been done.

However, the formation of a hard film by a chemical vapor deposition method has been studied. For example, Patent Document 1 describes a gas group A composed of NH ₃ , N ₂ and H ₂ , CrCl ₃ , AlCl ₃ , and Al (CH ₃ ). _{3. By} separately supplying the gas group B consisting of N ₂ and H ₂ as the raw material gas for the hard film, the surface of the tool base material is coated with the hard film made of nitrides of Al and Cr having a cubic structure. It is disclosed.

JP-A-2017-80883

The coating described in Patent Document 1, according to the study of the present inventors, when coating hard film comprising a nitride or a carbonitride of Al and Cr in the chemical vapor deposition, and NH ₃ gas is an alkaline gas, halogen Since CrCl ₃ gas and AlCl ₃ gas, which are gases, may react excessively and the film formation may become difficult to stabilize, and further, since they do not have a specific surface orientation, they are used as a coating tool including a coating cutting tool. It was confirmed that the durability may not be sufficient.
Therefore, an object of the present invention is to obtain a coating tool coated with Al and Cr nitrides or carbonitrides having excellent durability.

In the tool according to the embodiment of the present invention,
The hard film on the surface of the base material has an average content ratio of 50 atomic% or more for Al, 10 atomic% or more for Cr, and 90 atoms for the total content of Al and Cr with respect to the total amount of metal elements including metalloids. % Or more nitride or carbonitride,
The hard film has the maximum peak intensity due to the fcc structure in X-ray diffraction.
It is composed of a collection of columnar particles grown in the film thickness direction with respect to the surface of the base material.
The hard film has an X-ray diffraction intensity ratio TC (311) of 1.30 or more.
An intermediate film containing Ti nitride or carbonitride is provided between the base material and the hard film.

Further, the tool according to the embodiment preferably satisfies one or more of the following items.
(1) The X-ray diffraction intensity ratio TC (311) is 2.00 or more.
(2) The X-ray diffraction intensity ratio TC (311) is the X-ray diffraction intensity ratio TC (hkl) (however, the (hkl) plane is the (111) plane, the (200) plane, the (220) plane, and (311). ), (222), (400), (331) and (420).)
(3) The values of the X-ray diffraction intensity ratios TC (420) and TC (200) are less than 1.00.
(4) When the total peak intensity of the fcc structure in the X-ray diffraction is TA and the peak intensity due to the (422) plane is TB, the TB / TA value of the hard film is 0.050 or more.
(5) The average width of the columnar particles on the surface side is 0.1 μm or more and 2.0 μm or less.
(6) The hard film has a single-layer structure portion having a relatively high Al content ratio and a laminated structure portion having a relatively low Al content ratio in a microstructure using a transmission electron microscope. The crystal particles to have are dispersed.

According to the above, it is possible to obtain a coating tool coated with Al and Cr nitrides or carbonitrides having excellent durability.

It is a drawing substitute photograph (magnification 10,000 times) of the scanning electron microscope (SEM) image which shows the cross section of the rake face of the coating cutting tool of Example 1. FIG. It is a schematic schematic diagram with respect to the drawing substitute photograph of FIG. 1A. It is a drawing substitute photograph (magnification 200,000 times) of the image of the transmission electron microscope (TEM) of the hard film of Example 1. It is a schematic schematic diagram with respect to the drawing substitute photograph of FIG. 2A. It is a drawing substitute photograph (magnification 2,000,000 times) of the TEM image which enlarged the part A of FIG. It is a schematic schematic diagram with respect to the drawing substitute photograph of FIG. 3A. It is a drawing substitute photograph which shows the nanobeam diffraction pattern in the part B of the drawing substitute photograph of FIG. 3A. It is a drawing substitute photograph (magnification 4,000,000 times) of the TEM image which enlarged part C of the drawing substitute photograph of FIG. 3A. It is a schematic schematic diagram with respect to the drawing substitute photograph of FIG. 5A. It is a drawing substitute photograph which shows the nanobeam diffraction pattern in the part D of the drawing substitute photograph of FIG. 5A. It is a drawing substitute photograph which shows the nanobeam diffraction pattern in part E of the drawing substitute photograph of FIG. 5A. It is a figure which shows the X-ray diffraction measurement result of Example 1. FIG. It is a schematic schematic diagram of the chemical vapor deposition apparatus (CVD furnace) used for coating the hard film of an Example. It is a schematic schematic diagram which enlarged the main part of the chemical vapor deposition apparatus (CVD furnace) used for coating the hard film of an Example. It is the schematic sectional drawing of the gas outlet of the chemical vapor deposition apparatus (CVD furnace) used for coating the hard film of an Example. It is a schematic schematic diagram of the chemical vapor deposition apparatus (CVD furnace) used for coating the hard film of Comparative Example 2. FIG. 5 is a schematic cross-sectional view of a gas ejection port of a chemical vapor deposition apparatus (CVD furnace) used for coating the hard film of Comparative Example 2. It is a schematic diagram of the chemical vapor deposition apparatus (CVD furnace) used for coating the hard coating of Comparative Examples 3 and 4. It is the schematic sectional drawing of the gas outlet of the chemical vapor deposition apparatus (CVD furnace) used for coating the hard film of Comparative Examples 3 and 4.

The present inventor controls the orientation of the (311) plane of a nitride or carbonitride mainly composed of Al and Cr when used as a coating film for a coating cutting tool having a large machining load among tools. We arrived at the present invention by discovering that the durability is improved, and thinking that this finding can be applied to all of the above-mentioned covering tools. That is, for the nitrides or carbon nitrides mainly composed of Al and Cr, the X-ray diffraction intensities of each crystal plane were obtained, and the X-ray diffraction intensities of the (311) plane were focused on and arranged. We have obtained the surprising finding that the durability of the covering tool is improved when the X-ray diffraction intensity has a certain relationship with the diffraction intensity of the other surface.

Further, in order not to excessively react the raw materials gas of NH ₃ gas which is an alkaline gas, CrCl ₃ gas which is a halogen gas and AlCl ₃ gas, N ₂ gas and H of the amount of NH ₃ gas in the mixed gas of these raw material gases are not excessively reacted. _{It was also found} that the ratio to the total amount of the _two gases should be specified, and that Cr chloride gas should be generated in the CVD furnace.

Hereinafter, the component composition, structure, crystal structure, and characteristics of the hard film constituting the covering tool according to the embodiment of the present invention, and the details of the manufacturing method and the manufacturing apparatus thereof will be described.

<Composition>
First, the composition of the hard film according to the present embodiment will be described.
The hard film according to this embodiment is a nitride or carbonitride based on Al and Cr. The Al and Cr nitride or carbonitride film is a film having excellent wear resistance and heat resistance. More preferably, it is a hard film of the nitride having excellent heat resistance. Even when the hard film is a carbonitride, when the total content ratio (atomic%) of nitrogen and carbon is 100% in the average composition of the hard film, the nitrogen content ratio (atomic%) is 80% or more. It is preferable to have. If the hard film is mainly composed of nitrides having excellent heat resistance, the durability of the covering tool will not be significantly reduced even if a part of the hard film contains nitrides or the like. More preferably, when the total content ratio (atomic%) of nitrogen and carbon is 100%, the nitrogen content ratio (atomic%) is 90% or more. The carbon contained in the hard film may be contained as free carbon.

<< Aluminum Al >>
When the average content ratio of Al is high, the heat resistance of the hard film is increased, and a lubrication protective film is easily formed on the tool surface, so that the durability of the coated tool is improved. In order to sufficiently reproduce these effects, the hard film according to the present embodiment has an average Al content of 50 atoms with respect to the total amount of metal elements including metalloids (hereinafter referred to as metal elements). % Or more. Furthermore, it is preferable that the Al content ratio is 55 atomic% or more. Furthermore, it is more preferable that the Al content ratio is 60 atomic% or more. Further, it is more preferable that the average content ratio of Al is 70 atomic% or more. However, if the Al content ratio becomes too high, the amount of AlN having a fragile hcp (hexagonal close-packed) structure increases, and the durability of the covering tool decreases. Therefore, it is preferable that the average content ratio of Al is 90 atomic% or less.

<< Chrome Cr >>
If the average content ratio of Cr is too small, AlN having a fragile hcp structure increases too much, and the durability of the covering tool decreases. In addition, it becomes difficult for a lubricating protective film to be formed on the tool surface (in the case of a cutting tool, the cutting edge surface), and welding is likely to occur. Therefore, the average content ratio of Cr is set to 10 atomic% or more. Further, the average content ratio of Cr is preferably 15 atomic% or more. However, if the Cr content is too high, the Al content is relatively low and the heat resistance is low. Therefore, the Cr content ratio is preferably 45 atomic% or less.

<< Other elements >>
The hard film according to the present embodiment preferably has an average content ratio of Al and Cr of 90 atomic% or more in order to impart higher heat resistance to the hard film. Furthermore, it is preferable that the average content ratio of the total of Al and Cr is 95 atomic% or more. The hard film according to this embodiment may contain a metal element other than Al and Cr. For example, Ti, Si, Zr, B, V may be contained. These elements are elements generally added to AlTi-based nitrides or carbonitrides and AlCr-based nitrides or carbonitrides, and if added in a small amount, the durability of the covering tool is significantly reduced. Depending on the application of the tool, it contributes to the improvement of durability.

That is, in a nitride or carbonitride having an average total content ratio of Al and Cr of 90 atomic% or more, if the X-ray diffraction intensity ratio TC (311) described later is set to a certain value or more, these metal elements can be removed. Even if it is contained, it does not significantly reduce the durability of the coated tool, and contributes to the improvement of durability depending on the application of the tool. However, if the average content ratio of metal elements other than Al and Cr becomes too high, the basic characteristics of Al and Cr-based nitrides or carbonitrides deteriorate, and the durability of the covering tool deteriorates. Therefore, when other metal elements are contained, the average content ratio is preferably 10 atomic% or less. The hard film according to this embodiment may be a nitride of Al and Cr.

<< Inevitable Impurities >>
The hard film according to the present embodiment may contain 1% by mass or less of components contained in the film-forming gas such as oxygen and chlorine as unavoidable impurities when the entire hard film is 100% by mass. If the hard film according to the present embodiment is a nitride or a carbonitride as a whole, a compound may be partially contained due to these impurities.

<Crystal structure>
In the hard film according to the present embodiment, one of the X-ray peak intensities (peak intensities) due to the fcc (face-centered cubic lattice) structure shows the maximum intensity in X-ray diffraction, and the fcc structure is the main component. Hard films mainly composed of hcp structures and amorphous hard films have low hardness and are fragile, and the durability of the covering tool is significantly reduced. When the peak strength due to the fcc structure shows the maximum strength, the hardness and toughness of the hard film are increased, and the durability of the covering tool is improved.

The hard film according to the present embodiment preferably has a single structure having an fcc structure, but if any of the peak intensities due to the fcc structure shows the maximum strength, the hcp structure is partially contained. May be good. For example, in the milling process of mild steel of HRC30 or less, a hcp structure may be contained because a high hardness is not required for the hard film. However, if the content ratio of the hcp structure becomes too high, the durability of the covering tool decreases. Therefore, even when the hcp structure is contained, it is preferable that the maximum peak intensity due to the hcp structure is 1/10 or less of the maximum peak intensity due to the fcc structure.

The hard film according to the present embodiment has a (111) plane, (200) plane, (220) plane, (311) plane, (222) plane, (400) plane, and (331) plane of the fcc structure in X-ray diffraction. It has peak intensities on at least nine faces, (420) and (422) faces. The present inventor has found that the number of fine columnar particles increases as the X-ray diffraction intensity ratio due to the (311) plane increases.

Therefore, in the present embodiment, the X-ray diffraction intensity ratio TC (311) described below is set to 1.30 or more with respect to the X-ray diffraction intensity ratio caused by the (311) plane. Then, the X-ray diffraction intensity ratio TC (311) caused by the (311) plane is changed from the 9th plane to the (422) plane because there is no (422) plane in the standard X-ray diffraction intensity of aluminum nitride. By increasing the X-ray diffraction intensity ratio of 8 surfaces excluding the above, the film structure becomes finer, the plastic deformation of the hard film is suppressed, and the film wear is easily suppressed, which is also preferable. I found out.

In this embodiment, the X-ray diffraction intensity ratio TC (hkl) of each surface including the (311) surface is obtained by obtaining the X-ray diffraction intensity ratio TC (hkl) represented by the following formula (Equation 1), and X-ray diffraction is performed. The intensity ratio TC (311) is evaluated.
(Equation 1)
TC (hkl) = {I (hkl) / I _O (hkl)} / [Σ {I (hkl) / I _O (hkl)} / 8]
I (hkl): X-ray diffraction intensity of the (hkl) surface of the actually measured aluminum nitride chromenium nitride and aluminum nitriding aluminum chromenium hard film.
I _O (hkl): Standard X-ray diffraction intensity of the (hkl) plane of aluminum nitride according to ICDD (International Center for Diffraction Data) file number 00-025-1495.
Σ means the sum of the following eight planes.
(Hkl) = (111) plane, (200) plane, (220) plane, (311) plane, (222) plane, (400) plane, (331) plane and (420) plane.

Here, since the standard X-ray diffraction intensities of aluminum nitride and aluminum nitride are not in the same file, the standard X-ray diffraction of aluminum nitride is similar to the X-ray diffraction of aluminum nitride and aluminum nitride. The diffraction intensity is used.

According to the diffraction angle 2θ and the standard X-ray diffraction intensity _IO corresponding to each crystal plane of the fcc structure aluminum nitride described in ICDD file No. 00-025-1495, the fcc structure aluminum nitride has a (420) plane. It can be confirmed that the X-ray diffraction intensity of is high. Further, since the standard X-ray diffraction intensity of the aluminum nitride does not have the (422) plane, the X-ray diffraction intensity ratio TC (hkl) is obtained from the above-mentioned eight planes.

By making the nitride or carbonitride mainly composed of Al and Cr a nitride or carbonitride mainly composed of Al and Cr having an X-ray diffraction intensity ratio TC (311) value of 1.30 or more. , The durability of the covering tool can be improved. Furthermore, it is more preferable that the X-ray diffraction intensity ratio TC (311) is 1.80 or more. Furthermore, it is even more preferable that the X-ray diffraction intensity ratio TC (311) is 2.00 or more. The upper limit of the X-ray diffraction intensity ratio TC (311) is not particularly limited, but when a nitride or carbonitride is produced by the method disclosed in the present specification, it is estimated that the upper limit is about 6.00. The upper limit is more preferably 5.00.
Furthermore, it is even more preferable that the X-ray diffraction intensity ratio TC (311) is larger than the X-ray diffraction intensity ratio TC (hkl) of other crystal planes.

The hard film according to the present embodiment preferably has an X-ray diffraction intensity ratio TC (420) and an X-ray diffraction intensity ratio TC (200) of 1.00 or less. The reason is that the value of the X-ray diffraction intensity ratio TC (hkl) between the (420) plane and the (200) plane, which have high peak intensities in the standard X-ray diffraction intensity, becomes smaller, so that the X-ray diffraction intensity ratio TC (311) This is because the value of is likely to be high, which is preferable. Further, it is more preferable that the values of the X-ray diffraction intensity ratio TC (420) and the X-ray diffraction intensity ratio TC (200) are 0.50 or less.

The X-ray diffraction peaks of the aluminum nitride chromenium nitride and the aluminum chromenium nitride hard film are similar to the X-ray diffraction peaks of the titanium aluminum nitride hard film, and the peak positions overlap. Therefore, when the hard film according to the present invention and the titanium aluminum nitride and aluminum nitrocarbium nitride hard film are laminated, for example, alternately laminated, the obtained X-ray diffraction peak is used as the peak of the aluminum chromenium nitride hard film for X-ray analysis. The intensity ratio TC (hkl) may be calculated.

In the X-ray diffraction, the hard film according to the present embodiment has the total peak intensity of the fcc structure (the sum of the peak intensities of the eight planes plus the X-ray diffraction peak intensities of the (422) plane) in TA. When the peak intensity caused by the (422) plane is TB, the TB / TA value is preferably 0.050 or more. Normally, the peak intensity on the high angle side such as the (422) surface is relatively weak, but the higher the peak intensity on the (422) surface, the hard film with higher crystallinity is formed and the durability of the covering tool is improved. improves. Further, setting the TB / TA value to 0.070 or more tends to improve the durability, which is more preferable.

Although ICDD file number 00-025-1495 does not have the peak intensity of the (422) plane, the peak intensity of the (422) plane can be confirmed in the X-ray diffraction diagram by calculating the plane spacing d value. ..

<Columnar particles>
The hard film according to the present embodiment is composed of a collection of columnar particles (columnar structure) grown in the film thickness direction with respect to the surface of the base material. The durability of the covering tool is improved by forming the hard film of the nitride or carbonitride based on Al and Cr into columnar particles grown in the film thickness direction with respect to the surface of the base material.

The average width of the columnar particles on the surface side is preferably 0.1 μm or more and 2.0 μm or less. By setting the average width on the surface side to 0.1 μm or more, the durability of the covering tool is further enhanced. Further, when the average width on the surface side is 2.0 μm or less, plastic deformation of the hard film is less likely to occur, and the particle size falling off from the hard film is reduced, so that tool wear is easily suppressed.

The surface side in the present embodiment means the vicinity of the surface of the hard film on the side in contact with the material to be processed, for example, the vicinity of the CP (Cross-section Policeher) processed surface. The width of the columnar particles of the hard film can be measured by observing the cross section with a transmission electron microscope or a scanning electron microscope. The measurement location was set at a depth of 0.5 μm from the surface of the film on the side in contact with the work material. By observing the widths of 30 or more consecutive columnar particles, the average value of the particle widths converges. Therefore, the average width of the columnar particles of the hard film may be obtained from 30 or more continuous columnar particles.

<Micro tissue>
The microstructure of the hard film according to this embodiment is not particularly limited. That is, it may have crystal particles having only a single layer structure. Further, it may have crystal particles having only a laminated structure. It may have crystal particles having only a single layer structure, crystal particles having only a laminated structure, and crystal particles having both a single layer structure and a laminated structure. In particular, it is preferable that crystal particles in which a single-layer structure and a laminated structure coexist are dispersed in one particle.

Specifically, for example, as shown in FIGS. 2A and 2B, one crystal particle contains Al and Cr nitrides or carbonitrides having a relatively high Al content ratio and a relatively Al content. A portion having a laminated structure in which Al and Cr nitrides or carbonitrides having a low ratio are alternately laminated, and a portion having a single-layer structure of Al and Cr nitrides or carbonitrides having a high Al content ratio. It is preferable that the crystal particles having the above are dispersed in the microstructure (see FIGS. 3A, 3B, 5A, and 5B for enlarged views).

Since the single-layer structure portion has relatively higher crystallinity than the laminated structure portion, it is presumed that there is less distortion. Therefore, the durability of the covering tool is improved because the crystal particles have a single-layer structure portion. Since the Al content ratio of the laminated structure portion is relatively smaller than that of the single layer structure portion, the Al content of the crystal particles as a whole increases too much, and the AlN of the fragile hcp structure increases. Is suppressed. The presence of such particles in the microstructure enhances the wear resistance and heat resistance of the hard film as a whole, and can exhibit excellent durability.

In the portion of the laminated structure of the crystal particles, the nitride or carbonitride of Al and Cr having a relatively high Al content ratio preferably has an Al content ratio of 60 atomic% or more, and is relatively The Al and Cr nitrides or carbonitrides having a low Al content preferably have an Al content of 55 atomic% or less.

In the portion of the laminated structure of the crystal particles, the nitride or carbonitride of Al and Cr having a relatively high Al content is more preferably 70 atomic% or more, and more preferably 80 atoms. % Or more is even more preferable. However, if the Al content ratio becomes too high, AlN in the hcp structure increases, so the Al content ratio is preferably 95 atomic% or less. Further, it is more preferably 90 atomic% or less.

The Al and Cr nitrides or carbonitrides having a relatively low Al content in the laminated structure of the crystal particles preferably have an Al content of 50 atomic% or less, and more preferably 40. It is even more preferably atomic% or less. However, if the Al content ratio is too low, the heat resistance of the entire hard film is lowered, so the Al content ratio is preferably 10 atomic% or more. Furthermore, 20 atomic% or more is more preferable.

The monolayer structure portion of the crystal particles preferably has an Al content of 60 atomic% or more. Furthermore, the Al content ratio is preferably 70 atomic% or more. However, if the Al content ratio becomes too high, the AlN of the hcp structure increases. Therefore, it is more preferable that the Al content ratio of the monolayer structure portion of the crystal particles is 90 atomic% or less.
The microstructure of the hard film according to the present embodiment may be composed of crystal particles having only a laminated structure or a single layer structure.

<Average film thickness>
The average film thickness (layer thickness) of the hard film according to the present embodiment is preferably 1.0 μm or more and 15.0 μm or less. The reason is that if the film thickness is less than 1.0 μm, the tool life is not sufficient because it is thin, while if the film thickness exceeds 15.0 μm, the film thickness becomes too thick and the machining accuracy may decrease. Is. The lower limit of the film thickness is more preferably 2.0 μm, further preferably 3.0 μm, and even more preferably 5.0 μm. The upper limit of the film thickness is more preferably 12.0 μm, and even more preferably 10.0 μm.

<Intermediate film and upper layer>
In the covering tool of the present embodiment, an intermediate film containing Ti nitride or carbonitride is provided between the base material of the tool and the hard film. By providing such an interlayer film, the adhesion between the base material and the hard film is further improved, and the durability is improved even in a harsh usage environment. Here, in the present specification, when a compound is not represented by a chemical formula like Ti nitride and carbonitride, it is not necessarily limited to those in the stoichiometric range, and Ti nitride or carbonitride is used. Including means that the presence of a layer that is inevitably formed when a Ti nitride or Ti carbonitride is formed as an intermediate layer is allowed.

Further, an upper layer having a different component ratio and a different composition from the hard film according to the present embodiment may be provided on the hard film according to the present embodiment. The upper layer is, for example, an oxide such as nitride, carbonitride, carbide or alumina, and may be provided via a bonding layer. Of these, alumina, which is generally used as a coating layer to be deposited by a chemical vapor deposition method, is preferable because it improves the heat resistance of the coating tool.

For example, in general, a coated cutting tool provided with alumina is used in the cutting process of a casting. When the covering tool of the present invention is also used as a cutting tool, it is preferable to provide alumina as an upper layer as needed because the durability is further improved. Further, as the upper layer, an Al and Ti nitride, an Al and Cr nitride or carbonitride having a relatively high Al content, and an Al and Cr nitride having a relatively low Al content, or A laminated film in which carbonitrides are alternately laminated may be provided.
Further, when the covering tool of the present invention is applied to a mold, V nitride or carbonitride having excellent lubricity may be provided on the upper layer.

<Treatment after coating>
Since the hard film according to the present embodiment has tensile stress because it is formed by chemical vapor deposition, it is preferable to perform post-coating treatment such as stress release by a blasting device or the like after coating. By performing this post-coating treatment, the coating cutting tool has improved chipping resistance and becomes a hard film having excellent tool life.

<Base material>
In the present embodiment, the base material (base material of the covering tool) is not particularly limited, and can be appropriately selected depending on the application, purpose, and the like. For example, cemented carbide, cold tool steel, high speed tool steel, plastic mold steel, hot tool steel and the like can be applied.

When the covering tool of the present invention is used as a cutting tool, the tool base material is not limited to the insert base material, for example, a drill, a cutting edge exchangeable cutting tip for drilling, a cutting edge exchangeable cutting tip for milling, a metal saw, and a reamer. , Taps and other substrates can be mentioned.

<Manufacturing method>
In the hard film according to the present embodiment, for example, the mixed gas A and the mixed gas B described below are separately introduced into a chemical vapor deposition apparatus (CVD furnace) in which the internal temperature is raised to 750 ° C. or higher, which will be described later. By mixing in the apparatus, a tool substrate such as an insert substrate placed in advance in the apparatus can be coated.

<< Mixed Gas A >>
In the present embodiment, the mixed gas A includes a mixed gas a1 and a mixed gas a2. Mixed gas a1 is the HCl gas and H ₂ gas (also referred to as "mixed gas for obtaining the mixed gas a1" or "mixed gas to produce chloride Cr"), of the gas the 2 contacts the metal Cr This is a gas containing Cr chloride gas (not only a component that can be expressed by CrCl ₃ but also a gas in which Cr and Cl are chemically bonded), and a typical composition is Cr / H ₂ chloride in terms of volume ratio. = 0.008 or more and 0.140 or less. On the other hand, the mixed gas a2 is a gas containing AlCl ₃ gas and H ₂ gas, and a typical composition is AlCl ₃ / (H ₂ + N ₂ ) = 0.0006 or more and 0.0300 or less in terms of volume ratio.
The volume% of the volume%, and AlCl ₃ gas chloride Cr gas, as described later, estimated from HCl gas amount to be introduced in order to generate these gases.

In the mixed gas a1, although HCl gas and H ₂ gas for the production of chloride Cr gas is contacted with the heated metal Cr, the heat, as described later in the description of the manufacturing apparatus, the inside of the CVD furnace It is preferably performed in the gas preheating section. Further, it is preferable to obtain the mixed gas A by mixing the mixed gas a1 having Cr chloride gas with the mixed gas a2 heated near the temperature of the mixed gas a1. By doing so, it becomes easy to generate Cr chloride gas without being affected by AlCl ₃ gas.

The temperature at which the Cr chloride gas is generated in the gas preheating section is set to a temperature at which Cr chloride gas of about 750 ° C., which is the minimum set temperature of the furnace temperature, is stably generated. The reason is that if this temperature is too low, the amount of Cr chloride gas generated decreases, the entire hard film becomes Al-rich, and AlN in the hcp structure tends to increase.

Further, the AlCl ₃ gas contained in the mixed gas a2 can be generated by introducing, for example, a mixed gas of H ₂ gas and an HCl gas into an AlCl ₃ gas generator filled with metal Al and kept at 330 ° C. It is preheated when it is mixed with the mixed gas a1 to form the mixed gas A. It is preferable that the temperature of the mixed gas a2 is not so different from the temperature of the mixed gas a1 because the hard film has a structure composed of aggregates of columnar particles, and is close to the temperature of the mixed gas a1 (for example,). ± 80 ° C) is good.

In the mixed gas A obtained by mixing the mixed gas a2 with the mixed gas a1, it is preferable to maximize the flow rate of the H ₂ gas. It may further contain N ₂ gas and Ar gas in the gas mixture a1 and mixed gas a2.

<< Mixed Gas B >>
The mixed gas B includes H ₂ gas, N ₂ gas and NH ₃ gas. The composition ratio of this mixed gas B is 0.002 or more and 0.020 or less in the value of b2 / b1 when the total volume% of the N ₂ gas and the H ₂ gas is b1 and the volume% of the NH ₃ gas is b2. Is preferable in order to obtain the composition of the hard film according to the present embodiment. If the composition ratio of the mixed gas B is within this composition ratio range, it is easy to prevent the NH ₃ gas, which is an alkaline gas, from excessively reacting with the CrCl ₃ gas or AlCl ₃ gas, which are halogen gases.

This mixed gas B is also preheated, but the temperature rise due to the preheating is suppressed, and the temperature rise is suppressed to be lower than the temperature of the mixed gas A to avoid excessive preheating.
In the coating device described later, the gas flow path of the mixed gas B in the preheating chamber is set to be the same as the height of the preheating chamber, so that the mixed gas B is prevented from being excessively preheated like the mixed gas A. .. As a result, the reaction rate of NH ₃ contained in the mixed gas B and the Cr chloride gas and AlCl ₃ gas contained in the mixed gas A is suppressed, and the hard film becomes a structure composed of aggregates of columnar particles.

The gas flow path of the mixed gas B passes through the gas preheating section, but as described above, the preheating temperature is suppressed and excessive preheating is avoided. As one means for preheating in this way, a flow path of a mixed gas for obtaining a mixed gas a1 as a heat source for preheating, a mixed gas a2, as in the preheating part of the CVD furnace used in the present embodiment described later. The total length of the gas flow path of the mixed gas a1 and the length of the gas flow path of the mixed gas a2 is 3 more than that of the gas flow path of the mixed gas B. It is conceivable to increase the length in the range of 2 times or more, preferably 5 times or more, and 8 times or less.

This range may be appropriately determined depending on the capacity of the device, and may be 10 times, or even 20 times. As an example, the flow path of the mixed gas B is preferably 650 mm or less, and more preferably 550 mm or less. As a result, the excessive reaction between NH ₃ gas and AlCl ₃ gas or Cr chloride gas is suppressed, and the hard film becomes a structure composed of aggregates of columnar particles.

The gas flow path of the mixed gas for obtaining the mixed gas a1, the gas flow path of the mixed gas a2, and the gas flow path of the mixed gas B are from the introduction of each mixed gas into the furnace until the completion of preheating. Refers to the flow path of. That is, as described later, it refers to a connection flow path that rotates during film formation and a flow path in the preheating chamber (preheating chamber), such as the preheating part of the CVD furnace used in the present embodiment.

<< Mixing of mixed gas A and mixed gas B and introduction into the furnace >>
When the mixed gas A and the mixed gas B are mixed in advance and introduced into the CVD furnace (inside the reaction vessel) from one nozzle hole, the reaction rate between the NH ₃ gas and the AlCl ₃ gas or Cr chloride gas becomes too fast. , It becomes difficult to obtain a structure composed of aggregates of columnar particles in a hard film.

Therefore, the mixed gas A and the mixed gas B are not mixed before being introduced into the CVD furnace (inside the reaction vessel), and the nozzle hole of the mixed gas A and the nozzle hole of the mixed gas B are separately provided in the CVD furnace. Introduce independently into (inside the reaction vessel). Specifically, for example, as described in the manufacturing apparatus described later, the nozzle hole of the mixed gas B has a different ejection direction from the nozzle hole of the mixed gas A, and further, the rotation axis is larger than the nozzle hole of the mixed gas A. The reaction rate between the NH ₃ gas and the AlCl ₃ gas or Cr chloride gas should not be too fast by arranging the distance from the outside.

<< Reaction pressure and film formation temperature >>
The reaction pressure for film formation is preferably 3 kPa or more and 5 kPa or less. The reason is that if the reaction pressure is too low, the film formation rate decreases, while if the reaction pressure is too high, the reaction is promoted and it is difficult to obtain a structure composed of aggregates of columnar particles. ..

The temperature inside the CVD furnace (inside the reaction vessel) is preferably 750 ° C. or higher and 850 ° C. or lower. The reason is that if the film formation temperature is too low, the amount of chlorine in the hard film increases and the wear resistance decreases, while if the film formation temperature is too high, the reaction is promoted and the film is composed of aggregates of columnar particles. This is because it is difficult to obtain the organization to be used. The temperature inside the furnace is more preferably 770 ° C. or higher and 820 ° C. or lower.

When coating the carbonitride, a gas that gives a carbon component, that is, a hydrocarbon gas having 2 to 5 (C2 to C5) carbon atoms (for example, ethane) or a hydrogen carbonitride gas (for example, acetonitrile) is mixed. It is preferable to introduce the gas a2 together with the gas a2 into the CVD furnace. By introducing highly reactive ethane or acetonitrile, the carbonitride can be stably coated. The amount of the hydrocarbon gas introduced is preferably 0.4% by volume or less with respect to the amount of the sum of the mixed gas A and the mixed gas B.

<Coating device>
In the chemical vapor deposition apparatus (CVD furnace) used in one embodiment of the present invention, the temperature inside the furnace (inside the reaction vessel) is 750 ° C. or higher and 850 ° C. or lower, and in the furnace (inside the reaction vessel) in order to carry out the above-mentioned manufacturing method. The pressure can be 3 kPa or more and 5 kPa or less, and has the following characteristic configuration. A specific configuration will be described in Examples described later, and here, items to be provided as an apparatus will be mainly described.

The coating device independently preheats each of the three types of mixed gas, the mixed gas a1 and the mixed gas a2 for generating the Cr chloride gas which is a component of the mixed gas A, and the mixed gas B, in the CVD furnace ( It has a configuration to be introduced into the reaction vessel).

That is, the CVD furnace has a gas preheating unit and an outgassing unit for introducing gas into the reaction vessel described later. The gas preheating section
(1) A Cr chloride gas generating unit that generates a mixed gas a1 containing a Cr chloride gas by bringing a mixed gas for generating a Cr chloride gas into contact with a metal Cr.
(2) First preheating section for preheating the mixed gas a2,
(3) A second preheating section for preheating the mixed gas B, and
(4) A mixing section in which the mixed gas a1 and the mixed gas a2 are mixed to form a mixed gas A.
And have.

The heat source of the preheating section may be provided independently for the preheating section, or a heat source (heater) provided on or near the peripheral wall of the CVD furnace may be used. Further, the metal Cr has a shape such as flakes in which Cr chloride gas is easily generated.

Here, when the heat source of the CVD furnace is used as one means for adjusting the temperature of the mixed gas as described above in the preheating section, for example, the mixed gas a1 is added to the heater of the CVD furnace which is the preheating source. The gas flow path to be generated, the gas flow path of the mixed gas a2, and the gas flow path of the mixed gas B are brought closer to each other in this order, and the arrangement of the gas flow paths is devised to generate the mixed gas a1 as an example. The total length of the length of the flow path of the mixed gas a2 and the length of the flow path of the mixed gas a2 is 3 times or more, preferably 5 times or more, and 8 times or less the length of the flow path of the mixed gas B.

Here, the length of the flow path of the gas that generates the mixed gas a1, the length of the flow path of the mixed gas a2, and the length of the flow path of the mixed gas B are, respectively, from the gas introduction port of the CVD furnace to the gas preheating section. The length to the exit. That is, as described later, it refers to a connection flow path that rotates during film formation and a flow path in the preheating chamber (preheating chamber), such as the preheating part of the CVD furnace used in this embodiment.

With such a configuration, the mixed gas a1 is preheated to 750 ° C. or higher, while the mixed gas a2 is preheated to a temperature in the vicinity of the mixed gas a1, for example, ± 80 ° C., and is combined with the mixed gas a1. It can be mixed to obtain a mixed gas A. On the other hand, the temperature of the mixed gas B (TeB) is lower than the temperature of the mixed gas A (TeA) (TeA> TeB).

As for the mixed gas A, since the gas flow path in the preheating section is long, the temperature has risen to about the temperature inside the furnace. On the other hand, with respect to the mixed gas B, since the gas flow path in the preheating portion is shortened, it can be said that the temperature rise is suppressed.

Further, in the CVD furnace, a first pipe provided with a nozzle hole for introducing the mixed gas A into the reaction vessel and a nozzle hole for introducing the mixed gas B into the reaction vessel are provided as gas discharge parts. It has a second pipe. For example, there are two second pipes, which are arranged so as to face the outside of one first pipe, and these pipes are centered on the axis of the first pipe at a speed of 2 to 5 revolutions / minute. It is preferable to rotate.

Here, if the nozzle hole of the mixed gas A and the nozzle hole of the mixed gas B are too close to each other, a rapid reaction occurs, it becomes difficult to obtain a structure composed of aggregates of columnar particles, and the film thickness distribution of the hard film becomes difficult. become worse. On the other hand, if the nozzle hole of the mixed gas A and the nozzle hole of the mixed gas B are too far apart, the gas supply becomes insufficient and the film thickness distribution becomes poor. Therefore, as an example, as shown in FIG. 9C, the distance from the nozzle hole of the mixed gas A and the rotating shaft (the axis of the first pipe) is H1, the nozzle hole of the mixed gas B and the rotating shaft (the first pipe). When the distance from the axis) is H2, the lower limit of H2 / H1 is preferably 1.5, the upper limit is preferably 4, and more preferably 3.

Further, it is preferable that the gas ejection direction of the mixed gas A from the nozzle hole and the gas ejection direction of the mixed gas B from the nozzle hole are arranged with a deviation of 30 degrees to 90 degrees.

Hereinafter, the present invention will be described with reference to examples applied to a coated cutting tool, but the present invention is not limited thereto.

<Coating device>
In this embodiment, the chemical vapor deposition apparatus (CVD furnace) 1 shown in FIGS. 9A, 9B and 9C was used as a schematic schematic diagram. The outline of this device will be described.
The CVD furnace 1 has a cylindrical chamber 2, a heater 3 provided inside the peripheral wall of the chamber 2, and a plurality of insert installation plates 4 for installing a large number of insert base materials (tool base materials) 20 in the chamber 2. It has a reaction vessel 5, a connection flow path 11 provided in the lower part of the reaction vessel 5, and a preheating chamber 6 which is a preheating section.

The preheating chamber 6 is
A mixed gas for generating Cr chloride gas introduced from the gas flow path 82 is dispersed in the radial direction of the preheating chamber 6 via the connection flow path 11 in a cylindrical shape, and the Cr chloride gas generation chamber 62. Space to be introduced in
A Cr chloride gas generation chamber 62 that is provided directly above this space, has a cylindrical space at the center where the outer circumference of the cylinder coincides with the outer circumference of the preheating chamber 6, and is concentric with the preheating chamber 6.
A preheating chamber 61 (first preheating unit) formed concentrically with the preheating chamber 6 in the cylindrical space at the center of the Cr chloride gas generation chamber 62 and preheating the mixed gas a2 introduced from the gas flow path 81,
A mixing chamber 63 (mixing section) located above the Cr chloride gas generation chamber 62 and the preheating chamber 61 and mixing the mixed gas a1 and the mixed gas a2, which will be described later, to form a mixed gas A.
have.

Further, in the preheating chamber 6, that is, the axial center portion of the preheating chamber 61, there is a flow path (second preheating section) through which the mixed gas B introduced from the gas flow path 91 penetrates in the height direction thereof. The path is connected to the outer flow path of the pipe 7 at the upper part of the preheating chamber 6, which has the shortest length (550 mm) of passing through the preheating portion. On the other hand, the flow path of the mixed gas A mixed in the mixing chamber 63 is provided so as to be connected to the central flow path of 2 of the pipe 7 at the upper part of the preheating chamber 6.

The mixed gas introduced from the gas flow path 82 is introduced into the Cr chloride gas generator 62 in the preheating chamber 6, reaches the furnace temperature of 750 ° C. or higher, reacts with the metal Cr in the generation chamber, and is Cr chloride. It becomes a mixed gas a1 containing a gas and is introduced into the mixing chamber 63.

Then, as described above, the mixed gas B is introduced into the outer flow path of the pipe 7 and is introduced into the reaction vessel 5 from the nozzle holes 91a and 91b. On the other hand, the reaction gas A introduced from the gas flow paths 81 and 82 and penetrating the preheating chamber 61 is introduced into the central flow path of the pipe 7 and introduced into the reaction vessel 5 from the nozzle holes 83a and 83b.

Here, as shown in the gas ejection port cross-sectional view of FIG. 9C, the positional relationship between the nozzle holes 83a and 83b and the nozzle holes 91a and 91b is such that the nozzle holes 91a and 91b have a rotation axis of the pipe 7 rather than the nozzle holes 83a and 83b. It is arranged outside O1, and H2 / H1 is 2 when the distance between the nozzle holes 91a and 91b and the rotating shaft O1 is H2 and the distance between the nozzle holes 83a and 83b and the rotating shaft O1 is H1. The ejection directions of the nozzle holes 91a and 91b and the ejection directions of the nozzle holes 83a and 83b form an angle of 90 degrees.

The connection flow path 11, the preheating chamber 6 and the pipe 7 shown in FIG. 9B 12 are configured to rotate at a speed of 2 rotations / minute, but in FIGS. 9A, 9B and 9C, this rotation occurs. The illustration of the required configuration is omitted.

Although the specific configuration is not shown in FIGS. 9A and 9B, the total length of the length of the gas flow path for obtaining the mixed gas a1 and the length of the gas flow path of the mixed gas a2 is shown in FIG. 9B. It is configured to be about four times the length of the gas flow path of the mixed gas B, which is the total of 13a, 13b, and 13c shown in 1.

≪Base material≫
As the substrate, WC based cemented carbide (10 mass% of Co, 0.6 wt% of _Cr 3 _{C 2,} balance WC and inevitable impurities) manufactured by milling insert (manufactured by Mitsubishi Hitachi Tool WDNW14520) and , WC based cemented carbide (7 wt% of Co, 0.6 wt% of _Cr 3 _C 2, 2.2 wt% of ZrC, 3.3 wt% of TaC, 0.2 wt% NbC, balance WC An insert for evaluating physical properties (ISO standard SNMN120408) made of (consisting of unavoidable impurities) was prepared.

≪Coating of interlayer film≫
In Examples 1 to 7, a titanium nitride film was formed as an intermediate film. First, the substrate was set in a CVD furnace 1 shown in FIG. 9A, the temperature of the CVD furnace 1 is raised to 800 ° C. while introducing _{H 2} gas. Thereafter, at 800 ° C. and 12 kPa, from the gas inlet of the preheating chamber 6 through the gas passage 81, 83.1% by volume of _{H 2} gas, 15.0% by volume of _{N 2} gas, TiCl 1.9 vol% _A mixed gas composed of _four gases was introduced into the preheating chamber 62 and flowed into the reaction vessel 5 from the first nozzle holes 83a and 83b of the pipe 7 at a flow rate of 67 L / min to form a titanium nitride film.
Table 1 shows the film forming conditions of the interlayer film.

≪Covering of hard film≫
<< Process of obtaining mixed gas a1 >>
After reducing the pressure in the CVD furnace 1 to 4kPa while introducing H ₂ gas, the gas flow path 82 of the preheating chamber 6 shown in FIG. 9A, and a mixed gas of _{H 2} gas and HCl gas was kept to 400 ° C. ..

The Cr chloride gas generation chamber 62 of the preheating chamber 6 preheated to 800 ° C. is filled with Cr metal flakes (purity 99.99%, size 2 mm to 8 mm), and H ₂ gas and HCl introduced from the gas flow path 82. reacting a mixed gas of the gas to produce a mixed gas a1 is a mixed gas of chloride Cr gas and H ₂ gas was introduced into the mixing chamber 63.

<< Process of obtaining mixed gas A and introducing it into the reaction vessel from the nozzle hole >>
From the gas inlet of the preheating chamber 6 through the gas passage 81, and preheated by introducing a mixed gas a2 obtained by mixing H ₂ gas and AlCl ₃ gas into the preheating chamber 62.
Then, the mixed gas a1 and the mixed gas a2 were mixed in the mixing chamber 63 to obtain a mixed gas A having a temperature near 800 ° C., which is the temperature of the preheating chamber. Then, the obtained mixed gas A was introduced into the reaction vessel furnace through the first nozzle holes 83a and 83b of the pipe 7. The total flow rate of the mixed gas A was 48.75 L / min.

<< Process of introducing mixed gas B into the reaction vessel from the nozzle hole >>
A mixed gas B composed of H ₂ gas, N ₂ gas and NH ₃ gas was introduced into the gas flow path 91, and was introduced into the furnace through the second nozzle holes 91a and 91b of the pipe 7. The total flow rate of the mixed gas B was 30.25 L / min.

Here, when the value of NH ₃ / (AlCl ₃ + CrCl ₃ ) is in the range of 0.18 to 0.39, the excess reaction between the NH ₃ gas and the halogen gas CrCl ₃ gas or AlCl ₃ gas is caused. It can be suppressed more reliably, and a hard film having a nitride based on Al and Cr can be stably formed.

In this way, in Examples 1 to 7 and Comparative Example 1, the nitrides of Al and Cr having a film thickness of about 6 μm were formed on the interlayer film shown in Table 1 by a chemical vapor deposition method with each mixed gas composition shown in Table 2. A coated cutting tool was manufactured by covering an object. Here, Comparative Example 1 does not satisfy the mixed gas composition preferred in one embodiment of the present invention.

As for the amount of Cr chloride gas and AlCl ₃ gas generated, the composition of the mixed gas was determined by setting 1/3 of the amount of HCl gas introduced into the Cr chloride gas generation chamber as the amount of Cr chloride gas.

In Comparative Example 2, a hard film was prepared using the CVD furnaces shown in FIGS. 10A and 10B. First, the configuration of this CVD furnace will be briefly described. In FIGS. 10A and 10B, members having the same reference numerals as those in FIGS. 9A and 9C represent the same members as those in the drawings. In this CVD furnace, the mixed gas is introduced from the gas flow path 92, and the mixed gas is introduced into the reaction vessel 5 from the nozzle hole 92a provided in the pipe 7. Although the pipe 7 rotates, the configuration required for the rotation is not shown.

In Comparative Example 2, a titanium nitride film, which is an intermediate film, was formed on the substrate in the same manner as in Example 1 under the same film forming conditions as in Example 1 (see Table 1). After that, the pressure in the CVD furnace 1 was lowered to 1 kPa while flowing H ₂ gas at 800 ° C., and then H ₂ gas, N ₂ gas, CrCl ₃ gas, and AlCl _{3 having the} compositions shown in Table 2 were introduced into the gas flow path 92. A mixed gas of gas and NH ₃ gas was introduced and introduced into the reaction vessel 5 through the nozzle hole 92a of the pipe 7. In this way, a coated cutting tool was manufactured by coating the insert base material with a nitride film of Al and Cr having a film thickness of about 6 μm on the intermediate film by a chemical vapor deposition method.

In Comparative Example 3, a hard film was prepared using the CVD furnaces shown in FIGS. 11A and 11B. First, the configuration of this CVD furnace will be briefly described. In FIGS. 11A and 11B, the members having the same reference numerals as those in FIGS. 9A and 9C represent the same members as those in the drawings. In this CVD furnace, the mixed gas introduced from the gas flow path 84 is independent of the nozzle hole 94a provided in the nozzle 7, and the mixed gas introduced from the gas flow path 93 is independent of the nozzle hole 94a provided in the nozzle 7. Is introduced into the reaction vessel 5. Although the pipe 7 rotates, the configuration required for the rotation is not shown.

In Comparative Example 3, a titanium nitride film, which is an intermediate film, was formed on the substrate in the same manner as in Example 1 under the same film forming conditions as in Example 1 (see Table 1). Then, the pressure in the CVD furnace 1 was lowered to 4 kPa while flowing H ₂ gas at 800 ° C., and then H ₂ gas, N ₂ gas, CrCl ₃ gas, and AlCl _{3 having the} compositions shown in Table 2 were introduced into the gas flow path 84. The mixed gas A of the gas is introduced into the reaction vessel 5 through the nozzle hole 84a of the pipe 7, and the mixed gas composed of H ₂ gas, N ₂ gas and NH ₃ gas is introduced into the gas flow path 93 having the composition shown in Table 2. B was introduced and introduced into the reaction vessel 5 through the nozzle hole 93a of the pipe 7. In this way, a coated cutting tool was manufactured by coating the insert base material with a nitride film of Al and Cr having a film thickness of about 6 μm on the intermediate film by a chemical vapor deposition method.

In Comparative Example 4, a hard film was prepared using the same CVD furnace as in Comparative Example 3. A titanium nitride film, which is an intermediate film, was formed on the substrate in the same manner as in Example 1 under the same film forming conditions as in Example 1 (see Table 1). After that, the pressure in the CVD furnace 1 was lowered to 4 kPa while flowing H ₂ gas at 800 ° C., and then H ₂ gas, N ₂ gas, CrCl ₃ gas and AlCl _{3 having the} compositions shown in Table 2 were introduced into the gas flow path 84. The mixed gas A of the gas is introduced into the furnace through the nozzle hole 84a of the pipe 7, and the mixed gas B composed of H ₂ gas, N ₂ gas and NH ₃ gas having the composition shown in Table 2 is introduced into the gas flow path 93. Was introduced into the furnace through the nozzle hole 93a of the pipe 7. In this way, a coated cutting tool was manufactured by coating the insert base material with a nitride film of Al and Cr having a film thickness of about 6 μm on the intermediate film by a chemical vapor deposition method.

In addition, about Example 7, the upper layer was provided. The upper layer is formed by forming the nitride film mainly composed of Al and Cr according to this embodiment, and then forming the bonding layer and the aluminum oxide layer in this order.

That is, first, in order to form a bonding layer composed of a Ti (CN) layer and a Ti (CNO) layer, 63.5 volumes are passed from the gas inlet of the preheating chamber 6 through the gas flow path 81 at 1000 ° C. and 16 kPa. A mixed gas consisting of% H ₂ gas, 22.0% by volume N ₂ gas, 3.2% by volume CH ₄ gas, and 1.3% by volume TiCl ₄ gas was introduced into the preheating chamber 62, and the pipe 7 was introduced. first nozzle holes 83a of, with flow in the reaction vessel furnace from 83 b, the gas flow path 91, to introduce 10% by volume of _{H 2} gas, the second nozzle holes 91a of the pipe 7, into the furnace from 91b It was poured to form a Ti (CN) layer having a thickness of 0.5 μm. 51.3% by volume H ₂ gas, 30.7% by volume N ₂ gas, 3.0% by volume CH ₄ gas, 1.2% by volume TiCl ₄ gas, 3 at 1000 ° C. and 16 kPa continuously. A mixed gas consisting of 0.0% by volume CO gas and 0.8% by volume CO ₂ gas was introduced into the preheating chamber 62 and flowed into the reaction vessel furnace through the first nozzle holes 83a and 83b of the pipe 7 and at the same time. 10% by volume of H ₂ gas was introduced into the gas flow path 9 and flowed into the furnace through the second nozzle holes 91a and 91b of the pipe 7 to form a Ti (CNO) layer having a thickness of 0.5 μm.

Further, at 1000 ° C. and 9 kPa, 9.2% by volume of AlCl ₃ gas, 85.3% by volume of H ₂ gas, 4.3% by volume of CO ₂ gas, and 0.2% by volume of H ₂ S. A mixed gas composed of gas and 1.0% by volume HCl gas was introduced into the preheating chamber 62 and flowed into the reaction vessel furnace through the first nozzle holes 83a and 83b of the pipe 7, and also into the gas flow path 9. 10% by volume of H ₂ gas was introduced and flowed into the furnace through the second nozzle holes 91a and 91b of the pipe 7 to form an aluminum oxide layer having a thickness of 1 μm.

Comparative Example 5 was coated using an arc ion plating apparatus. Using an alloy target of Al ₇₀ Cr ₃₀ (numerical value is atomic ratio) without providing an interlayer film, the bias voltage of the negative pressure applied to the substrate is -100V, and nitrogen gas is introduced into the furnace to control the pressure inside the furnace. A coated cutting tool was manufactured by coating about 3 μm of Al and Cr nitrides at 3 Pa and a furnace temperature of 500 ° C.

Next, with respect to Examples 1 to 7 and Comparative Examples 1 to 5, the composition of the hard film, the measurement of the crystal structure, and the evaluation of machinability were carried out as follows.

≪Composition of hard film≫
Cross section of insert for physical property evaluation (SNMN120408) using an electron probe microanalyzer (EPMA, JXA-8500F manufactured by JEOL Ltd.) under the conditions of an acceleration voltage of 10 kV, an irradiation current of 0.05 A, and a beam diameter of 0.5 μm. The composition of the hard film was determined from the average of the measured values obtained by measuring arbitrary 5 points at the center of the aluminum nitride hard film in the film thickness direction. The measurement results are shown in Table 3.

≪Measurement of crystal structure≫
Using an X-ray diffractometer (EMPYREAN manufactured by PANalytical), CuKα1 line (wavelength λ: 0.15405 nm) was applied to the surface of the hard film on the rake face of the insert for physical property evaluation (SNMN120408) at a tube voltage of 45 kV and a tube current of 40 mA. The crystal structure of the hard film was evaluated by irradiation.

The ICDD X-ray diffraction database was used to identify the diffraction peaks. Since there is no data in ICDD for the fcc structure aluminum nitride chromenium hard film, the ICDD file of fcc structure aluminum nitride was substituted.

From the obtained X-ray diffraction pattern, the X-ray diffraction intensity ratio TC (hkl) was determined by the following formula (Equation 2).
(Number 2)
TC (hkl) = {I (hkl) / I _O (hkl)} / [Σ {I (hkl) / I _O (hkl)} / 8]
I (hkl): The measured X-ray diffraction intensity of the (hkl) surface of the aluminum nitride chromenium hard film.
I _O (hkl): Standard X-ray diffraction intensity of the (hkl) plane of aluminum nitride according to ICDD file number 00-025-1495.
Σ means the sum of the following eight planes.
(Hkl) = (111) plane, (200) plane, (220) plane, (311) plane, (222) plane, (400) plane, (331) plane and (420) plane.
The results are shown in Table 3.

≪Cutting evaluation≫
The coated milling insert was attached to a cutting edge replaceable rotary tool (ASRT5063R-4) with a set screw, and the tool life of the hard film was evaluated under the following milling conditions. The flank wear width of the hard film was measured by observing with an optical microscope at a magnification of 100 times. The machining time to reach the total cutting length when the maximum wear width of the flank exceeds 0.350 mm was measured in units of 5 minutes as the tool life. The processing conditions are shown below. The test results are shown in Table 3.

Work material: S55C (30HRC)
Processing method: Milling Insert shape: WDNW140520
Cutting speed: 150 m / min Rotation speed: 758 revolutions per minute Feed per blade: 2.05 mm / tooth
Feed rate: 1554 mm / min Axial depth of cut: 1.0 mm
Radial depth of cut: 40 mm
Cutting method: Dry cutting

1A and 1B show SEM image photographs (magnification: 10,000 times) of the rake face of the physical property evaluation insert (SNMN120408) according to Example 1, respectively, and a schematic diagram thereof. From FIGS. 1A and 1B, it can be seen that Example 1 is composed of a set of columnar particles grown in the film thickness direction with respect to the surface of the base material. The details of the microstructure will be described later.

FIG. 8 shows the X-ray diffraction pattern of Example 1. In this X-ray diffraction pattern, the diffraction peak of the WC of the WC-based cemented carbide base material and the diffraction peak of the aluminum nitride hard film having an fcc structure are observed. From the X-ray diffraction pattern of FIG. 8, it can be seen that the aluminum nitride hard film of Example 1 has a single structure of fcc structure. Table 4 shows the X-ray diffraction intensity ratio TC (hkl) obtained from the X-ray diffraction pattern of FIG. Similarly, Tables 5 and 6 show the X-ray diffraction intensity ratio TC (hkl) of Examples 2 and 3, respectively. In addition, in Tables 4 to 6, since the X-ray diffraction intensity ratio TC (422) cannot be obtained, it is displayed as “−”.

As shown in Tables 4 to 6, it was confirmed that the X-ray diffraction intensity ratio TC (311) in Example 1 was the largest value as compared with the other X-ray diffraction intensity ratios. It is presumed that this is the reason why the tool life of Example 1 is longer than that of other Examples. On the other hand, in Comparative Example 1, as shown in Table 7, the X-ray diffraction intensity ratio TC (311) is not the largest value as compared with other X-ray diffraction intensity ratios. In Table 7, since the X-ray diffraction intensity ratio TC (422) cannot be obtained, it is indicated as “−”.

In Examples 1 to 7, wear resistance and chipping resistance were improved and excellent durability was exhibited. On the other hand, in Comparative Examples 1 to 5, film peeling occurred at an early stage. In all the comparative examples having poor durability, the value of the X-ray diffraction intensity ratio TC (311) was less than 1. On the other hand, in each of the examples having excellent durability, the film structure was a structure composed of a collection of fine columnar particles, and the value of the X-ray diffraction intensity ratio TC (311) was 1.30 or more. Among the examples, those having an X-ray diffraction intensity ratio TC (311) of 2 or more tended to have particularly excellent durability. Further, as the TB / TA value increases, the durability tends to be excellent.

Next, the hard film of Example 1 will be described. 2A and 2B show a TEM image photograph (magnification: 200,000 times) of the hard film according to Example 1, and a schematic schematic diagram thereof, respectively.

As shown in FIGS. 2A and 2B, crystal particles having a portion having a laminated structure and a portion having a single layer structure were confirmed in the hard film according to Example 1.

3A and 3B are TEM image photographs (magnification: 2,000,000 times) of an enlarged portion A of FIG. 1A, respectively, and schematic schematic diagrams thereof. As shown in FIGS. 3A and 3B, the hard film according to Example 1 has crystal particles having a portion having a laminated structure and a portion having a single layer structure even in the microstructure observed at a higher magnification. It was confirmed that there was.

FIG. 4 shows the nanobeam diffraction pattern of the B portion (single layer structure) of FIG. 3A. As shown in FIG. 4, the portion having a single-layer structure was composed of an fcc structure.

5A and 5B are TEM image photographs (magnification of 4,000,000 times) of the C portion (laminated structure) of FIG. 3A, respectively, and schematic schematic diagrams thereof. The relatively dark phase was a nitride of Al and Cr having a high Al content, and the relatively bright phase was a nitride of Al and Cr having a low Al content.

FIG. 6 shows the nanobeam diffraction pattern of the D portion (laminated structure) of FIG. 5A. Further, FIG. 7 shows the nanobeam diffraction pattern of the E portion (laminated structure) of FIG. 5A. As shown in FIGS. 6 and 7, it was confirmed that each layer of the laminated structure was also composed of the fcc structure.

The portion having a single-layer structure had an Al content of 60 atomic% or more and 90 atomic% or less. On the other hand, in the portion having a laminated structure, the nitride portion of Al and Cr having a relatively high Al content has an Al content of 60 atomic% or more and 95 atomic% or less, and has a relatively Al content. In the nitride portion of Al and Cr having a low ratio, the Al content ratio was 20 atomic% or more and 50 atomic% or less. As a whole, the portion having a laminated structure had a lower Al content ratio than the portion having a single-layer structure.

In the microstructure of the hard film according to Example 1 of the present invention, crystal particles having a monolayer structure portion having a relatively high Al content ratio and a laminated portion having a relatively low Al content ratio are contained in the structure. It was dispersed.

The disclosed embodiments are merely exemplary in all respects and are not restrictive. The scope of the present invention is shown by the scope of claims rather than the embodiment described above, and is intended to include meaning equivalent to the scope of claims and all modifications within the scope.

Since the covering tool of the present invention has excellent durability, it can also be used for cutting tools and dies such as press working and forging dies. It can also be applied to die-cast cast pins, nesters, and sliding parts that make up various machines.

1: Chemical vapor deposition equipment (CVD furnace)
2: Chamber 3: Heater 4: Insert installation plate 5: Reaction vessel 5a: Reaction vessel opening 6: Preheating chamber (preheating part)
61: Preheating chamber 62: Cr chloride gas generation chamber 63: Mixing chamber 7: Pipe (gas release part)
83a, 83b, 91a, 91b, 92a, 93a: Nozzle hole (gas outlet)
81: Gas flow path of the mixed gas a2 82: Gas flow path of the mixed gas to be the mixed gas a1 84: Gas flow path of the mixed gas 91: Gas flow path of the mixed gas B 92: Gas flow path of the mixed gas 93: Mixing Gas flow path 10: Exhaust pipe 11: Connection flow path 12: Rotating part during film formation 13a: Gas flow path of mixed gas B in the preheating chamber 13b: Gas flow path of mixed gas B in the connection flow path (vertical) direction)
13c: Gas flow path of mixed gas B in the connection flow path (direction of rotation axis)
20: Insert base material 30: Hard film (AlCrN film)
31: Laminated part 32: Single layer part 40: Resin during TEM observation

Claims (7)

A coating tool that has a hard film on the surface of the base material.
The hard film has an average content of 50 atomic% or more of Al, 10 atomic% or more of Cr, and 90 atomic% or more of the total content of Al and Cr with respect to the total amount of metal elements including metalloids. Nitride or carbonitride,
The hard film has the maximum peak intensity due to the fcc structure in X-ray diffraction.
It is composed of a collection of columnar particles grown in the film thickness direction with respect to the surface of the base material.
The hard film has an X-ray diffraction intensity ratio TC (311) of 1.30 or more.
A coating tool characterized in that an intermediate film containing Ti nitride or carbonitride is provided between the base material and the hard film. The covering tool according to claim 1, wherein the X-ray diffraction intensity ratio TC (311) is 2.00 or more. The X-ray diffraction intensity ratio TC (311) is the X-ray diffraction intensity ratio TC (hkl) (however, the (hkl) plane is the (111) plane, the (200) plane, the (220) plane, the (311) plane, The covering tool according to claim 1 or 2, characterized in that it is larger than (222) plane, (400) plane, (331) plane, and (420) plane.). The covering tool according to any one of claims 1 to 3, wherein the values of the X-ray diffraction intensity ratios TC (420) and TC (200) are less than 1.00. The hard film is characterized in that the value of TB / TA is 0.050 or more when the total peak intensity of the fcc structure in X-ray diffraction is TA and the peak intensity due to the (422) plane is TB. The covering tool according to any one of claims 1 to 4. The coating tool according to any one of claims 1 to 5, wherein the average width of the columnar particles on the surface side is 0.1 μm or more and 2.0 μm or less. In the microstructure using a transmission electron microscope, the hard film is composed of crystal particles having a monolayer structure having a relatively high Al content and a laminated structure having a relatively low Al content. The covering tool according to any one of claims 1 to 6, wherein the covering tool is dispersed.