JP3333080B2 - High-strength coated members with consistent interfaces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength coated member having a coherent interface formed by coating a coating of a compound of (TiAl) on a substrate of a metal, alloy or ceramic sintered body in a heteroepitaxial relationship. Specifically, a metal, alloy, or ceramic sintered body is coated with a high hardness and high toughness coating having excellent peel resistance, and is typically represented by a turning tool, a milling tool, a drill, and an end mill. Tools such as cutting tools, cutting blades such as slitters, cutting blades and dies, punches and other mold tools, and wear-resistant tools such as nozzles and other corrosion-resistant and wear-resistant members, and civil engineering tools such as bits The present invention relates to a high-strength covering member having an optimal coherence interface.

[0002]

2. Description of the Related Art Metal, alloy and ceramic substrates are coated with a ceramic film having a thickness of 20 μm or less,
Many coating members have been proposed that attempt to achieve a long life by effectively extracting the characteristics of the substrate and the coating. The method of coating the coating on the coating member is roughly classified into a chemical vapor deposition method (CVD method) and a physical vapor deposition method (PVD method). Among them, a coating coated by the PVD method has an advantage of increasing abrasion resistance without deteriorating the strength of the substrate. For this reason, coatings of coated cutting tools typified by drills, end mills, and throw-away inserts for milling, which generally emphasize strength and fracture resistance, are currently coated by a PVD method.

[0003] It is well known that a titanium nitride film is applied to improve wear resistance. However, metal nitrides typified by titanium nitride are liable to be oxidized at high temperatures, and have a problem that wear resistance is significantly deteriorated. In order to improve the problem of oxidation of the titanium nitride film, one proposed in the mid 1980's includes (Ti
There is a coating material represented by a coating film of an Al) compound.
No. 5, JP-A-6-210502, JP-A-6-210502
Japanese Patent Application Laid-Open No. 210511 and Japanese Patent Application Laid-Open No. 7-197235.

On the other hand, it has been proposed to improve the adhesion of a film by crystallizing a film to be coated on the surface of a substrate, as a typical example of which is disclosed in JP-A-56-156767.
JP, JP-A-2-159363, JP-A-5-2
87322, JP-A-5-287323 and JP-A-5-295517.

[0005]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open Nos. Sho 62-56565, Hei 6-210502, Hei 6-210 relate to TiAl compound coatings as prior art.
No. 511 and JP-A-7-197235 disclose a hard coating layer comprising a single layer or a multilayer of two or more of carbides, nitrides and carbonitrides of (TiAl) on the surface of a substrate. A surface-coated hard member having excellent abrasion resistance and having formed thereon is disclosed.

[0006] The surface-coated hard members disclosed in these publications are coated hard members having improved oxidation resistance and abrasion resistance as compared with the coating of a Ti compound as originally developed.
Conversely, there is a problem that the mechanical properties are deteriorated, and the cutting performance is deteriorated when applied to tools, particularly cutting tools used under severe conditions. In other words, the surface-coated hard member described in the publication, by incorporating Al in the coating, achieved improved chemical properties of the coating surface as compared to the coating of the Ti compound, but the base material and the coating Because the crystal structure at the interface is not considered, the peel resistance and strength of the coating are inferior, and the fracture toughness value and fracture resistance of the surface-coated hard member are reduced, especially when used as a high-speed cutting tool. In addition, there is a problem that the life of the coating is shortened due to oxidation of the coating due to high temperature, rapid progress of wear, deterioration due to thermal shock resistance, and welding to a work material.

On the other hand, JP-A-56-156767 and JP-A-Hei 2 156767 as prior art relating to a crystal oriented film.
JP-A-159363, JP-A-5-287322, JP-A-5-287323 and JP-A-5-2-2
Japanese Patent Application Laid-Open No. 95517 discloses a coated hard member in which a film of a Ti compound is crystallographically oriented and coated on the surface of a substrate.

[0008] Among these publications relating to crystal orientation, the crystal-oriented coated hard member disclosed in the above two publications does not maintain a heteroepitaxial relationship at the mutual interface between the base material and the coating. Orientation becomes weaker,
There is a problem that the adhesion of the coating and the strength of the coating are poor. Among these publications, the crystal-oriented coated hard members disclosed in the following three publications do not have a coating layer configuration in consideration of stress at the interface between the base material and the coating, and have a mechanical property of the coating itself. , There is a problem that the strength, hardness, abrasion resistance, heat resistance and peeling resistance of the coating cannot be satisfied yet.

The present invention has solved the above-mentioned problems, and specifically, has high toughness, high hardness, wear resistance, and oxidation resistance in a wide range from a low temperature range to a high temperature range. It is an object of the present invention to provide a high-strength coated member having a coherent interface that has a longer life by being coated with a coating having heat resistance, thermal shock resistance, fracture resistance, welding resistance, and a peeling-resistant coating.

[0010]

Means for Solving the Problems The present inventors have found that a coated member in which a hard film of a (TiAl) compound is coated on a cemented carbide base material exhibits an excellent effect when used in a low temperature region. On the other hand, while studying the problem that the effect is reduced when used in a high-temperature region, a heteroepitaxial relationship between a base material and a hard film made of a (TiAl) compound coated adjacent to the base material is considered. When covering to keep
The present invention has been found that a high-strength coating is obtained, and that abrasion resistance is not reduced from a low temperature to a high temperature region, and that the hard film has a remarkably improved peeling resistance and a longer life. Is completed.

The high-strength coating member of the present invention comprises a composite nitride, a composite carbonitride,
A coating member coated with a hard film of at least one kind of a composite nitride or composite carbonitride,
The surface of the substrate has a crystal structure mainly composed of hexagonal crystals,
20% or more of the substrate surface in contact with the hard film is (000
1) The base material and the hard film are formed such that the (0001) crystal surface of the base material surface is parallel to the (1-11) crystal plane of the crystal grains constituting the hard film. The interface is characterized by being coated in a heteroepitaxial relationship.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The base material of the high-strength coating member of the present invention is a metal member, a sintered alloy or a ceramic sintered body that can withstand the heating temperature when coating the coating. Are metal members represented by, for example, stainless steel, heat-resistant alloys, high-speed steels, die steels, Ti alloys, Al alloys, cemented carbides, cermets, sintered alloys of powdered high-speed steel, and Al ₂ O ₃ based sintering. Ceramic sintered body such as a sintered body, a Si ₃ N ₄ based sintered body, a sialon based sintered body, and a ZrO ₂ based sintered body. Among these, when used as a cutting tool or a wear-resistant tool, a substrate of a cemented carbide, a nitrogen-containing TiC-based cermet, or a ceramic sintered body is preferable.

The base material is preferably a cemented carbide containing hexagonal crystal grains as a main component. Among the cemented carbides, a super hard alloy having a large amount of (0001) crystal plane WC precipitated on its surface. Hard alloys are preferred. In the case of a substrate containing no hexagonal crystal grains or a substrate having a low content of hexagonal crystal grains, for example, WC, Mo ₂ C,
Cr ₂ N, TaN, VB ₂ , NbB ₂ , TaB ₂ , W ₂ B ₅ ,
A base material whose surface is coated with a thin film composed of one kind of single layer or two or more kinds selected from ceramics having a hexagonal crystal structure of MoB ₂ and CrB ₂ may be used.

The hard film coated on the surface of the substrate is, for example, (Ti, Al) N, (Ti, Al) C
N, (Ti, Al) NO and (Ti, Al) CNO. This hard film preferably has a thickness of 0.5 to 10 μm, and particularly for applications in which impact resistance is important, preferably has a thickness of 0.5 to 5 μm.

These hard films may be of stoichiometric or non-stoichiometric composition, but in particular, (Ti _a ,
Al _b ) C _y N _1-y [where Ti is titanium,
Al represents aluminum, a and b each represent the atomic ratio of Ti and Al, and y represents the atomic ratio of carbon. Also, a
+ B = 1, 0.25 ≦ a ≦ 0.75, 0 ≦ y ≦ 0.9
5) is preferable from the viewpoint of peeling resistance. In particular, a represents the atomic ratio of Ti in the above formula.
And y representing the atomic ratio of carbon are 0.4 ≦ a ≦
It is preferable to use a hard film having a relationship of 0.6 and 0 ≦ y ≦ 0.2 because the hard film has excellent properties such as strength and wear resistance.

In the high-strength coating member of the present invention, crystals on both surfaces of the substrate and the hard film at the interface between the substrate and the hard film are oriented. The surface of the substrate has a crystal structure mainly composed of hexagonal crystals, and has a surface of the substrate in contact with the hard film.
% Or more are (0001) crystal faces, and (00)
01) The crystal plane (1-11) of the crystal grain constituting the hard film
It is preferable that the <11-20> crystal direction of the base material surface be parallel to the crystal plane and the <110> crystal direction of the hard film be parallel to the strength and peel resistance of the film.

The high-strength coating member of the present invention is a metal member represented by stainless steel, a heat-resistant alloy, a high-speed steel, a die steel, a Ti alloy, an Al alloy, a cemented carbide, a cermet, which are conventionally commercially available. , Sintered alloy of powdered high-speed steel, Al ₂ O ₃ based sintered body, Si ₃ N ₄ based sintered body, Sialon based sintered body, ZrO
A ceramic sintered body of a ₂ series sintered body is used as a base material, and preferably, a superhard metal equivalent to P20 to P40, M20 to 40 and K10 to K20 classified in the selection criteria for use of cemented carbide according to JIS B4053. Alloy material, particularly preferably P
A substrate made of a cemented carbide material equivalent to 30, M20, or M30 may be used. The surface of this substrate is polished if necessary, and is subjected to a cleaning process using ultrasonic waves, an organic solvent, and the like.
It can be manufactured by coating a film on a substrate by a conventional physical vapor deposition method (PVD method), chemical vapor deposition method (CVD method) or plasma CVD method.

When a film is coated on a substrate, a PVD method, a CVD method, or a plasma CVD method is used according to the quality of each thin film and a hard film, including a hexagonal structure thin film to be coated as necessary. Can be used properly. Among these, it is preferable to perform all coatings from the manufacturing process by a PVD method typified by an ion plating method or a sputtering method. Among them, coating treatment is preferably performed by an ion plating method, particularly an arc ion plating method. Is preferred.

The case where the coating in the high-strength coating member of the present invention is produced by an ion plating method will be described in further detail. As the metal source, two types of metal titanium and metal aluminum may be used independently, or Ti-A
1 alloy may be used. The method of metal ionization is also
Any of glow discharge, high-frequency heating, and the like may be used in addition to arc discharge. The gas used in the ion plating method is
In addition to the gas for producing nitride, that is, nitrogen gas,
A compound gas such as ammonia containing nitrogen may be used. It is preferable to introduce this reaction gas into a furnace, ionize a metal or an alloy as a metal source, and apply a negative bias to the base material, because the crystal orientation of the film becomes easy.

[0020]

According to the high-strength coating member of the present invention, the hard film has an effect of improving the fracture toughness value and the wear resistance of the entire coating and an effect of relaxing the stress remaining near the interface between the base material and the hard film. In particular, in the case of a substrate made of a cemented carbide, it acts to enhance the adhesion, and the heteroepitaxial relationship provides excellent properties to the entire coating member.

[0021]

EXAMPLE A commercially available cemented carbide of the shape SNGN120408 (material equivalent to P30 of JIS B4053) was used as a base material, and the base material surface was washed with an organic solvent, and then placed in a chamber of an arc discharge plasma method. , (Installed using a jig capable of simultaneously covering the flank face and the rake face), and the chamber was evacuated to a vacuum of 1.0 × 10 ^{−6 to} 3.0 × 10 ⁻⁶ Torr. Next, the substrate was maintained at about 450 ° C., the arc discharge current was maintained at about 100 A, the inside of the chamber was maintained at the gas composition and gas pressure shown in Table 1, and the Ti—Al alloy was discharged for about 30 minutes to discharge (TiAl) N and A hard film of (TiAl) CN was synthesized. Ti-Al alloy as an evaporation source
Product 1 of the present invention using targets having different compositions shown in Table 1.
To 5 and Comparative products 1 to 3 were obtained. The coating conditions of the comparative product different from the coating conditions of the product of the present invention were that no hydrogen treatment was performed before the coating, that the gas pressure and bias voltage conditions were the same as those conventionally used, and that As the material, a cemented carbide containing a large amount of (0001) plane grown platelet WC was used, whereas the base material of the comparative product was a conventional commercially available material having the same composition as the product of the present invention. Is used.

The coatings of the inventive products 1 to 5 and the comparative products 1 to 3 thus obtained were examined with an X-ray diffractometer, an electron microscope, and an EDX device, and found to be a hard film of a (Ti, Al) compound. It was confirmed. The hard film composition components of Inventive Products 1 to 5 and Comparative Products 1 to 3 were analyzed by an X-ray diffractometer and a glow discharge optical emission analyzer, and are shown in Table 2.
The thickness of each coating was examined by a scanning electron microscope, and the results are shown in Table 2.

Next, products 1 to 5 of the present invention and comparative products 1 to
Using No. 3, a coating film was subjected to a scratch test by an apparatus corresponding to a scratch hardness tester, and a critical load at which the coating film was peeled was obtained. The results are also shown in Table 2. Also, using the products 1 to 5 of the present invention and the comparative products 1 to 3, a work material: S45C
(HB190), cutting speed 300m / min, feed:
0.5 mm / rev, depth of cut: 2.0 mm, cutting time:
A cutting test was performed by a dry cutting test for 60 minutes, and the average flank wear width was measured. The results are also shown in Table 2.

The heteroepitaxial relationship between the substrate and the hard film was confirmed using an electron diffraction method.
The products 1 to 5 of the present invention comprise 20% of the surface of the substrate in contact with the hard film
The above is the (0001) crystal plane, and the (00)
01) The crystal plane is (1-1) of a crystal grain constituting the hard film.
1) Being parallel to the crystal plane and <11-2 of the substrate surface
It was confirmed that the 0> crystal direction was parallel to the <110> crystal direction of the hard film. Table 3 shows the crystal orientation (rate) between the interfaces among these confirmation contents.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

According to the present invention, the high-strength coating member according to the present invention has a conventional (T
Compared to a comparative product coated with iAl) N coating, the coating has excellent peeling resistance, and the coating itself has high hardness, high toughness,
Due to its abrasion resistance, oxidation resistance, thermal shock resistance, chipping resistance, and welding resistance, it has a long life in the area corresponding to the medium to high speed cutting area in this field. effective. Therefore, the high-strength coating member of the present invention has an excellent effect that a long life can be achieved in a wide range from the low-speed cutting region to the high-speed cutting region, which is the region of the conventional coating member, particularly as an end mill and a drill. Since the coated member is coated with a coating having high toughness and high hardness, it can exert excellent effects in the light cutting region to the heavy cutting region.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mamoru Kohata 580 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Solid Square Toshiba Tungaloy Co., Ltd. In-house Examiner Soki Sera (56) References JP, A) JP-A-6-316756 (JP, A) JP-A-6-346226 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 C30B 29/10 C30B 29/38 C30B 23/08 B23B 27/14

Claims (4)

(57) [Claims] 1. A hard film comprising at least one of a composite nitride, a composite carbonitride, a composite carbonitride, and a composite carbonitride containing titanium and aluminum on a substrate, In the coated member, the surface of the substrate has a crystal structure mainly composed of hexagonal crystals, and at least 20% of the surface of the substrate in contact with the hard film is a (0001) crystal plane. The interface between the substrate and the hard film is coated in a heteroepitaxial relationship such that the (0001) crystal plane is parallel to the (1-11) crystal plane of the crystal grains constituting the hard film. A high-strength covering member having a characteristic consistency interface. 2. The hard film according to claim 1, wherein the hard film is composed of at least one of a composite nitride and a composite carbonitride containing titanium and aluminum represented by the following formula (A). A high-strength covering member having a coherent interface according to claim 1. (Ti _a , Al _b ) C _y N _1-y- (A) {wherein, Ti in the formula (A) represents titanium, Al represents aluminum, and a and b represent Ti and Al, respectively. The atomic ratio, y, represents the atomic ratio of carbon. Also, a + b = 1, 0.
25 ≦ a ≦ 0.75 and 0 ≦ y ≦ 0.95. ｝ 3. The coherent interface according to claim 1, wherein the <11-20> crystal direction of the substrate surface is parallel to the <110> crystal direction of the hard film. High strength coated member. 4. The method according to claim 1, wherein the base material is made of a cemented carbide containing hexagonal tungsten carbide as a main component. Strength coating member.