JPH0466838B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to diamond-coated parts suitable for cutting tools and wear-resistant tools. [Prior art] A method for manufacturing a diamond thin film or a diamond-like carbon thin film is disclosed in Japanese Patent Application Laid-open No. 53-10394 and Japanese Patent Application Laid-open No. 1983-10394.
-22616 and JP-A-58-91100, and an attempt to apply these methods to tools was made in JP-A-57-Sho.
-100989. This JP-A-57-
No. 100989 relates to a coated ceramic tool having a substrate made of Si ₃ N ₄ and/or SiC and coated with diamond. This coated ceramic tool aims to be effective as a wire drawing die or cutting tool by using Si ₃ N ₄ and/or SiC as a base material, which has high high-temperature strength and is difficult to undergo plastic deformation at high temperatures. . [Problems to be Solved by the Invention] Ceramic sintered bodies are broadly classified into oxide-based sintered bodies and non-oxide-based sintered bodies. Among these, examples of the former include Al ₂ O ₃ ceramic sintered bodies, ZrO ₂
Examples of the latter include Si ₃ N ₄ ceramic sintered bodies, SiC ceramic sintered bodies, and TiC ceramic sintered bodies. Based on sintered oxide ceramics,
Although it is possible to form a diamond coating layer directly on the surface, there is a problem in that the nucleation density of the diamond coating layer is too low and the effect of the diamond coating layer cannot be fully exhibited. When a non-oxide ceramic sintered body is used as a base, if the base is a ceramic sintered body made only of silicon nitride and/or silicon carbide, the constituent atoms are It has a small self-diffusion coefficient, decomposes and evaporates at high temperatures, and has a larger ratio of grain boundary energy to surface energy than ionic crystals or metal crystals, so it is inherently difficult to sinter. Therefore, a dense sintered body cannot be obtained, and the toughness is poor. Coated tools, in which a diamond coating layer is formed on the surface of a ceramic sintered body made only of silicon nitride and/or silicon carbide, cannot be used as cutting tools or wear-resistant tools because the substrate itself is brittle. However, there is a problem that the effect of the diamond coating layer cannot be fully exhibited. In addition, in order to increase the toughness of the substrate and make it a dense sintered body, metals are added to silicon nitride and/or silicon carbide.
A non-oxide ceramic sintered body to which a sintering aid made of an alloy or metal compound is added, for example, sintered by adding a sintering aid such as Al ₂ O ₃ , AlN, MgO, Y ₂ O ₃ to silicon nitride. A coated tool has a diamond coating layer formed on the surface of the base body made of this sintered body, and although the sintering aid contained in the base body improves the toughness inside the base body, the diamond coating layer and the base body are Since the sintering aid exists in some places in the form of a glassy substance or lower silicate at the boundary with the diamond coating, it may inhibit the adhesion strength between the substrate and the diamond coating layer, or may form a dense diamond coating layer. It's making it difficult. For this purpose, coated tools are made by forming a diamond coating layer directly on the surface of a dense non-oxide ceramic sintered body containing a sintering aid.
Since the adhesion between the coating layer and the substrate and the density of the coating layer are poor, there is a problem that sufficient effects cannot be exhibited even when used in cutting tools, etc., which have particularly severe usage conditions. The diamond-coated parts of the present invention solve the above-mentioned problems. Specifically, the diamond-coated parts of the present invention solve the above-mentioned problems. In contrast, the conventional problems were solved by forming an inner layer with excellent adhesion. [Means for solving the problem] In general, diamond has extremely poor wettability with other substances, has a low coefficient of thermal expansion, and also has low diffusion of other atoms into diamond. It is said to be difficult to coat the surface of a substrate made of material with diamond. Therefore, the present inventors investigated the optimal partner material for forming the diamond coating layer, and found that depending on the partner material,
The nucleation density during diamond nucleation differs greatly, and the higher the nucleation density, the higher the adhesion strength between the diamond coating layer and the other material, and the diamond coating layer becomes a fine crystal and dense coating layer. By confirming this, we have completed the present invention. That is, the diamond-coated parts of the present invention:
Carbides, nitrides, oxides, and borides of metals from groups 4a, 5a, and 6a of the periodic table, as well as aluminum oxide, aluminum nitride, boron carbide, boron nitride, silicon oxide, and their interactions are coated on the surface of a substrate made of a ceramic sintered body. A first inner layer consisting of a single layer of at least one type or a multilayer of two or more types in a solid solution, and a single layer or two layers of at least one type of silicon nitride, silicon carbide, and silicon nitride on the surface of the first inner layer. The second inner layer is made of multiple layers of more than one type, and the surface of the second inner layer is coated with an outer layer made of diamond and/or diamond-like carbon. Although the theoretical reason for the difference between the components of the diamond-coated parts of the present invention is not clear, the outer layer made of diamond and/or diamond-like carbon can exhibit the wear resistance of the outer layer and is not brittle. The thickness is preferably 0.1 μm to 20 μm in order to suppress chipping or chipping of the outer layer, which is apt to occur due to the material, and to avoid prolonging the process time for coating the outer layer.
Furthermore, when the outer layer made of diamond and/or diamond-like carbon is formed on the surface of the second inner layer made of silicon nitride, silicon carbide, or silicon nitride carbide, it tends to form fine crystal grains, and provides a dense and highly adhesive coating. become layers. In particular, when the second inner layer is silicon nitride and/or silicon carbide,
This is preferable because the outer layer consisting of diamond and/or diamond-like carbon tends to become finely crystallized and become denser. The second inner layer formed at this time can prevent soft carbon such as graphite or amorphous carbon from penetrating into the first inner layer, which is generated in the process of coating the outer layer made of diamond and/or diamond-like carbon. Moreover, it is preferable to set the thickness to 0.1 μm to 20 μm in view of the coating process time of the second inner layer and the strength within the second inner layer. In order to improve the adhesion between this second inner layer and the substrate, carbides, nitrides, oxides, borides of metals of groups 4a, 5a, and 6a of the periodic table, as well as aluminum oxide, aluminum nitride, boron carbide, boron nitride, and silicon oxide are used. A first inner layer made of a mutual solid solution of these is interposed between the second inner layer and the substrate. This first inner layer preferably has a thickness of 0.05 μm to 50 μm so as to enhance the adhesion between the second inner layer and the substrate and to prevent the strength within the first inner layer from decreasing. The total thickness of the outer layer, the second inner layer, and the first inner layer is preferably 2 μm to 10 μm when used under harsh conditions such as cutting tools, especially for parts with sharp cutting edges, For example, when used for a drilling tool such as a drill, 2 μm ~
A total coating layer thickness of 5 μm is preferred. The substrates include Al ₂ O ₃ sintered oxide ceramics, ZrO ₂ sintered, Si ₃ N ₄ sintered non-oxide ceramics, and SiC.
system sintered body, TiC system sintered body, TiB ₂ system sintered body, ZrB ₂ system sintered body
A sintered body etc. can be used. The type of the first inner layer that contacts the surface of the base body may be selected depending on the type of the base body. For example, in the case of a base body made of a Si ₃ N ₄ based sintered body, the first inner layer may be TiN, TaN, AlN,
A nitrogen-containing compound such as TiCN or TaCN is preferable, and in the case of a substrate made of an Al ₂ O ₃ based sintered body, the first
Inner layer is AlN, TiN, Tan, TiNC, TiNO,
Compounds such as TiCNO are preferred. The method for manufacturing a diamond-coated tool of the present invention includes:
After polishing, cleaning and drying the base surface made of ceramic sintered body, high temperature CVD method, plasma CVB method,
A first inner layer is coated on the surface of the substrate and a second inner layer is coated on the surface of the first inner layer by a conventional coating method such as sputtering, ion implantation, direct nitriding, or ion plating. After coating the second inner layer, it is heat treated in vacuum or in a non-oxidizing atmosphere if necessary. Next, the surface of the coated second inner layer is rubbed or polished with a metal brush or fine powder to activate the surface of the second inner layer and promote the generation of nuclei for forming the outer layer. After cleaning and drying, thermal filament CVD method, plasma CVD method, ion beam method, laser beam method,
An outer layer of diamond and/or diamond-like carbon is coated on the surface of the second inner layer by a conventional coating method such as an electron beam method, an ion implantation method, or a sputtering method. Generally, in the step of forming the outer layer, free carbon tends to precipitate in addition to diamond and/or diamond-like carbon, and this free carbon inhibits adhesion. When an outer layer is formed on the surface of the inner layer, the second inner layer on the side that contacts the outer layer becomes silicon carbide by the reaction shown in the following formula (1), Si ₃ N ₄ +3C→3SiC+2N ₂ (1) Contacting the first inner layer The second inner layer on the side to be coated consists of two layers of silicon nitride, and is a coating layer with no precipitation of free carbon and high adhesion strength. The first inner layer and the second inner layer described here include those having a stoichiometric composition or even those having a non-stoichiometric composition close to the stoichiometric composition.
In particular, in the second inner layer adhering to the outer layer, the silicon nitride may be α-Si ₃ N ₄ , β-Si ₃ N ₄ or a mixture thereof, and the silicon carbide may be α-SiC, β-SiC or other various crystals. The structure may be SiC or a mixture thereof, and silicon nitride includes Si ₄ N ₄ C. The diamond-like carbon as the outer layer includes amorphous but also crystalline material to some extent, and exhibits properties such as electrical resistance, light transmittance, and hardness that are close to those of diamond. [Function] The diamond-coated part of the present invention has an outer layer that is dense with fine crystals, and since this outer layer is made of diamond and/or diamond-like carbon that does not contain soft carbon, it has high hardness and excellent wear resistance. It is something that Furthermore, this outer layer has excellent adhesion because it is formed on the surface of the second inner layer. Further, in order to interpose a first inner layer with excellent adhesion to both the second inner layer and the substrate between the second inner layer and the substrate, a total covering layer consisting of the first inner layer, the second inner layer and the outer layer is provided. The overall peeling resistance is excellent. As long as the substrate for forming the first inner layer has a certain degree of plastic deformation resistance, strength, and high hardness, both an oxide ceramic sintered body and a non-oxide ceramic sintered body can be used. Such a diamond-coated part of the present invention is a coated part that has excellent wear resistance and peeling resistance, and also has excellent plastic deformation resistance, corrosion resistance, and oxidation resistance. [Example] Example 1 As a substrate, Si ₃ N ₄ -5% AlN - 10% by weight%
Y ₂ O ₃ ceramic sintered body (Si ₃ N ₄ system), Al ₂ O ₃ −
20%TiC-5%MgO ceramic sintered body (Al ₂ O ₃
A TiC-8%VC-8%NbC ceramic sintered body (TiC system) was polished into the CIS standard SNG432 shape, washed with distilled water and an organic solvent, and then dried. A diamond-coated part as shown in the figure was created. The TiN layer as the first inner layer was coated by CVD in an atmosphere of H ₂ +30% N ₂ +4% TiCl ₄ at a reaction system pressure of 100 Torr and a substrate temperature of 1000°C. The precipitation rate at this time is 1μm/hr
It was hot. In addition, the Si ₃ N ₄ layer coating as the second inner layer was coated with plasma using a high frequency wave of 13.56 MHz.
This was done using the CVD method. The coating conditions are high frequency output 200W, reaction system pressure 0.5Torr, and N ₂ +15%.
It was carried out in a SiH ₄ atmosphere. In this case, the coating speed is
It was 0.5 μm/hr. Furthermore, the outer diamond layer was coated by plasma CVD using microwaves at a frequency of 2450 MHz. The coating conditions are microwave output 300W and reaction system pressure 30Torr.
The coating was carried out in an H ₂ +1% CH ₄ atmosphere at a coating rate of 0.5 μm/hr to obtain a product of the present invention. For comparison, the diamond layer was directly coated on the substrate except for the steps of forming the first inner layer of the inner TiN layer and the second inner layer of the Si ₃ N ₄ layer, and then the second inner layer of the Si ₃ N ₄ layer was used.
A comparison product was obtained by removing the inner layer process and coating the first inner layer of TiN layer and the outer layer of diamond layer. The inventive product and comparative product obtained by these methods were compared to
Al-18%Si, cutting speed 750m/min, feed 0.1mm/
A machining test was conducted under cutting conditions of rev and depth of cut of 0.5 mm. The results are also listed in Table 1.

[Table] Example 2 Si ₃ N ₄ -4% MgO - 4% by weight as a substrate
Y ₂ O ₃ ceramic sintered body (Si ₃ N ₄ system), TiC-10
%TiN-10%NbC-10%VC ceramic sintered body (TiC type) was polished to the shape of CIS standard SNG432, washed with distilled water and an organic solvent, and dried, as shown in Table 2. A diamond-coated tool of the present invention was produced. The TiCN layer as the first inner layer was coated by CVD in a H ₂ + 15% N ₂ + 4% CH ₄ + 4% TiCl ₄ atmosphere at a system pressure of 80 Torr and a substrate temperature of 1000°C.
It was done according to the law. The precipitation rate at this time was 0.8μ
It was m/hr. Also, Si ₃ N ₄ as the second inner layer
The layer was coated by the sputtering method, targeting the Si ₃ N ₄ sintered body, in an Ar atmosphere with a vacuum degree of 5 × 10 ^-2
Torr, high frequency output of 300 W, and deposition rate of 1.8 μm/hr. After coating this second inner layer of Si ₃ N ₄ layer 2
Heat treatment was performed at 900° C. for 1 hour in a vacuum of ×10 ⁻⁵ Torr. Next, the outer layer, the diamond layer, is
20Torr, external heating 900℃, W filament temperature
Coating was carried out by a hot filament CVD method at 2200° C. using raw material gas H ₂ +0.5% C ₂ H ₆ . The deposition rate at this time was 1.2 μm/hr. For comparison, the diamond layer was directly coated on the substrate except for the process of forming the first inner layer of the inner TiNC layer and the second inner layer of Si ₃ N ₄ , and the TiNC layer was coated directly with the diamond layer except for the process of forming the second inner layer of Si ₃ N ₄ . A comparison product was obtained by coating the first inner layer of the layer and the outer layer of the diamond layer. The inventive product and the comparative product obtained by these methods were cut using an Al-10% Si alloy with four equally spaced slots as the work material, at a cutting speed of 150 m/min and a feed rate of 0.1 mm/min.
Intermittent machining tests were conducted under cutting conditions of rev and depth of cut of 1.0 mm. The results are also listed in Table 2.

〔effect〕

As a result, the diamond-coated parts of the present invention have excellent wear resistance and peeling resistance of the coating layer, so they can be used not only for static wear-resistant parts but also for applications where a certain degree of impact is applied, such as during machining. Not only tools, but also cutting tools including cutting tools that have intermittent cutting, milling tools, end mills, drills, drilling tools such as micron drills for semiconductor substrates, the pin tips of printing pins, paper, and cassettes. It is an industrially useful material that can be applied to wear-resistant tools, including slitters for cutting tapes.

Claims (1)

[Scope of Claims] 1. Carbides, nitrides, oxides, and borides of metals of groups 4a, 5a, and 6a of the periodic table, as well as aluminum oxide, aluminum nitride, boron carbide, and boron nitride, are present on the surface of a substrate made of a ceramic sintered body. , a first inner layer consisting of a single layer or a multilayer of at least one of silicon oxide and a mutual solid solution of these, and a surface of the first inner layer containing silicon nitride, silicon carbide,
A second inner layer made of a single layer of at least one type of silicon nitride or a multilayer of two or more types of silicon nitride, and an outer layer made of diamond and/or diamond-like carbon coated on the surface of the second inner layer. diamond-coated parts. 2. A diamond-coated component according to claim 1, wherein the first inner layer has a thickness of 0.05 μm to 50 μm. 3. A diamond-coated component according to claim 1 or 2, wherein the second inner layer has a thickness of 0.1 μm to 20 μm. 4. A diamond-coated component according to claim 1, 2 or 3, characterized in that the outer layer has a thickness of 0.1 μm to 20 μm.