JP3167374B2 - High adhesion diamond coated sintered alloy - 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-adhesion diamond-coated sintered alloy suitable as a cutting tool such as a turning tool, a milling tool, a drill, an end mill, or a wear-resistant tool such as a slitter, a wire cutter, and a guide. is there.

[0002]

2. Description of the Related Art Attempts have been made to apply a diamond-coated sintered alloy in which a diamond and / or diamond-like carbon film is formed on a base material surface of a sintered alloy represented by a cemented carbide to a cutting tool.

[0003] When a diamond-coated sintered alloy is used as a cutting tool, the biggest problem is the adhesion between the substrate and the coating.

Attention has been paid to the adhesion between the base material of the sintered alloy and the diamond coating, and many proposals have been made as diamond-coated sintered alloys suitable for cutting tools. No. 126972 and JP-A-63-53269.

[0005]

Problems to be Solved by the Invention JP-A-58-1269
No. 72 discloses that an inner layer adjacent to a base material of a cemented carbide is formed of carbides, nitrides, borides, oxides, compounds, mixtures, and Al of metals of Groups 4a, 5a, and 6a of the periodic table.
_A diamond-coated cemented carbide comprising at least one selected from the group consisting of ₂ O ₃ , AlN, B ₄ C, Si ₃ N ₄ , SiO ₂ , and SiC and having an outer layer made of diamond is disclosed. Specifically, the invention of the publication discloses that when a diamond coating is directly applied to a substrate of a cemented carbide containing Ni or Co, graphite is easily precipitated, and the adhesion between the substrate and the coating is significantly reduced. To solve the problem, WC is applied between the substrate and the coating by chemical vapor deposition (CVD) or physical vapor deposition (PVD).
And W ₂ C by interposing an inner layer.

[0006] However, the adhesion between the inner layer and the diamond coating disclosed in the publication has not reached a level that can be practically used as a cutting tool, and it is necessary to provide a separate step of forming the inner layer in the manufacturing process. There is a quality control problem that the complexity of the process and the control of the amount of carbon during the process of forming the inner layer affect the material of the diamond film and the adhesion between the substrate and the film.

[0007] JP-A-63-53269 discloses that
Disclosed is a diamond-coated cemented carbide obtained by etching the surface of a cemented carbide consisting of 4 wt% Co and tungsten carbide, and forming a diamond film by interposing an etching layer on the surface of the cemented carbide. I have.

[0008] The invention of the publication discloses that Co on the surface of the cemented carbide is
Is removed with an acid solution to form an etching layer, and a diamond film is formed on the surface of the etching layer.
In the void portion after o is removed, Co in the cemented carbide oozes out and is filled again when the diamond film is formed, so that diamond is likely to locally grow grains, and the diamond film and the etching layer There is a problem that the adhesion between the coating and the cemented carbide is low because graphite is easily generated at the interface of the alloy.

The present invention has solved the above-mentioned problems, and more specifically, has been proposed to suppress the generation of graphite during the formation of a diamond film by using a base material containing an intermetallic compound, and to provide a high quality diamond film. It is an object of the present invention to provide a diamond-coated sintered alloy capable of forming a diamond alloy and improving the adhesion between a substrate and a diamond coating.

[0010]

Means for Solving the Problems When forming a diamond film on the surface of a cemented carbide base material, the present inventors have proposed a method for suppressing graphite that precipitates on the surface of the base material and a method of adhering the base material and the film. Where we were thinking about enhancing
While the iron group metal contained as a binder phase in the base material acts to precipitate graphite during the formation of a diamond film, it is formed by the binder phase containing intermetallic compounds, especially the iron group metal in the binder phase. In the case of the binder phase containing the intermetallic compound to be obtained, it has been found that the deposition of graphite is suppressed during the formation of the diamond film, and that the adhesion between the substrate and the diamond film is significantly improved.

The present invention has been completed based on the above findings.

[0012] The high adhesion diamond-coated sintered alloy of the present invention comprises carbides of metals of Groups 4a, 5a and 6a of the periodic table,
The surface of the base material of the sintered alloy consisting of 80 to 99% by volume of one or more hard phases in the nitride and their mutual solid solution, and the balance consisting of a binder phase containing Co and / or Ni as a main component, has diamond and / or Or a diamond-coated sintered alloy formed with a diamond-like carbon film, wherein the binder phase contains the intermetallic compound, and the intermetallic compound is Co and / or Ni, Al and / or Si and the intermetallic compound with respect to the binder phase is contained in a volume ratio of 50% or more.

The hard phase constituting the base material of the coated sintered alloy of the present invention is, for example, when it is composed of only WC, it is mainly composed of WC, and in addition, TiC, ZrC, Hf
C, TaC, NbC, VC, Mo ₂ C, Cr ₃ C ₂ ,
(W, Ti) C, (W, Ta) C, (W, Ta, Ti)
C, (W, Ta, Nb, Ti) C, TiN, Ti (N,
C) and when these mutual solid solutions are contained, Ti
C or Ti (C, N) as a main component, and WC, Zr
C, HfC, TaC, NbC, VC, Mo ₂ C, Cr ₃ C
₂ , TiN, ZrN and their mutual solid solutions. When this hard phase is less than 80% by volume based on the whole base material, the binder phase is relatively 20%.
%, And as a result, the hardness of the substrate significantly decreases, and the abrasion resistance of the substrate at the point when the coating disappears is extremely deteriorated. %, The binder phase becomes relatively less than 1% by volume, and as a result, the strength of the base material is remarkably reduced, the base material is easily broken, and it is difficult to sufficiently exert the effect of the coating.

The binder phase constituting the base material of the coated sintered alloy of the present invention is one in which the main component Co and / or Ni contains an intermetallic compound. And / or Ni and an intermetallic compound, the main component of which is Co and / or Ni;
r, Hf, W, Mo, Cr, Fe and an intermetallic compound, wherein the intermetallic compound is NiS
i ₂ , CoSi ₂ , NiAl, Ni ₃ Al, CoAl, C
o ₂ Al ₅ , Ni ₃ (Al, W), Ni ₃ Si, Ni ₂ (A
1, Ti). This intermetallic compound contains Co and / or Ni and Al and / or Si, for example, NiSi ₂ , CoSi ₂ , NiAl, Ni ₃ A
1, CoAl, Co ₂ Al ₅ , Ni ₃ (Al, W), Ni ₃
It is particularly preferable to use at least one of Si and Ni ₂ (Al, Ti) because of a high effect of promoting the formation of a coating film. (Inter-compound 間 bonding phase × 100 ≧ 50%), and more preferably 80% or more in view of the peeling resistance of the coating and the effect of promoting the formation of the coating.

The film constituting the coated sintered alloy of the present invention may be a diamond film having a peak at about 1333 cm ^-1 indicating the crystal structure of diamond in Raman spectroscopic analysis, or a film of this diamond and other amorphous carbon. Or glass-like carbon, or may be made of diamond-like carbon which is said to exhibit properties close to diamond. The thickness of the coating must be selected depending on the application and shape. Particularly, in the case where the wear resistance is more important than the impact resistance, for example, 3 to 1
0 μm thickness is preferable, and 0.5 to 7 μm
Thickness is preferable. Among cutting tools, applications where impact resistance is important, such as milling cutting tools, or sharp angles, such as cutting tools such as drills and end mills, and wear-resistant tools such as slitters, cutting blades and cutting blades It is preferable that the shape having a sharp cutting edge is, for example, 0.5 to 3 μm thick and has a configuration in which the coating is thin.

In order to produce the coated sintered alloy of the present invention, a substrate is produced by applying a conventional powder metallurgy method, and then a pretreatment such as a flaw treatment or a cleaning treatment is performed on the surface of the substrate. And then subjecting it to a conventional diamond coating treatment by vapor phase synthesis.

[0017]

According to the high adhesion diamond-coated sintered alloy of the present invention, the intermetallic compound contained in the binder phase constituting the base material has an effect of suppressing the generation of graphite in the initial stage of film formation. Has the effect of promoting film formation, has the effect of increasing the strength and hardness of the substrate at high temperatures, and has the effect of increasing the adhesion between the film and the substrate after the film has been formed. Things.

[0018]

Example 1 Commercially available WC having an average particle size of 1.5 μm
Powder, W and Ni powder having an average particle diameter of 1.0 μm, and Al powder having an average particle diameter of 0.2 μm were blended into the compositions shown in Table 1. Next, the compounded powder was mixed and pulverized in a ball mill of an acetone solvent for 24 hours, dried and added with 1% by weight of paraffin, and then molded at a pressure of 1 t / cm ² to obtain a powder compact. 5-8 × 10
This was sintered at 1650 ° C. for 1 hour in a vacuum of ⁻² Torr to obtain a base material of a sintered alloy used for the present invention products 1 to 4 and comparative products 3 and 4.

The base material of the sintered alloy used for the comparative products 1 and 2 is as follows:
It was obtained in the same manner as described above except that it was sintered at 1450 ° C.

The intermetallic compounds in these substrates were confirmed by X-ray diffraction, SEM, and XMA, and the results are shown in Table 2.

After polishing and cleaning the surfaces of these substrates, 99 vol. Was obtained by microwave plasma CVD.
% -1 vol% CH ₄ gas atmosphere, 200 SCCM gas flow rate, 50 Torr pressure, 4 hours hold, 930-950
A diamond coating was formed so as to have a thickness of about 5 μm under the condition of the substrate temperature of ° C.

Observation of the state of the coating of the coated sintered alloy thus obtained revealed that the coatings of Comparative Products 1 and 2 had already been partially or completely removed when they were taken out of the reactor for forming the coating. On the other hand, the coatings of the products 1 to 4 of the present invention and the comparative products 3 and 4 did not peel off. Next, the present invention products 1-4
When a coating peeling test was performed on the coating surfaces of Comparative Products 3 and 4 by the Rockwell indenter press-fitting method, products 1 to 4 of the present invention
In Comparative Examples 3 and 4, no peeling of the film occurred near the indentation, whereas in Comparative Products 3 and 4, peeling of the film occurred near the indentation.

[0023]

[Table 1]

[0024]

Example 2 The WC and Al powders used in Example 1 and the Co powder having an average particle size of 3.0 μm were blended into the composition shown in Table 2, and the other steps were carried out in the same manner as in Example 1 to obtain the invention. Article 5
10 and comparative products 5 to 8 were obtained.

The coating surfaces of the thus obtained inventive products 5 to 10 and comparative products 5 to 8 were subjected to a coating peeling test by a Rockwell indenter press-fitting method under a load of 30 kg, and an indentation region formed by the Rockwell indenter and a region near the indentation region were formed. Table 2 shows the ratio of the average coating peeling deformation area to the average indentation area.
It was also described in. (Intermetallic compound ÷ bonded phase × 100)

[0026]

[Table 2]

[0027]

As described above, the high-adhesion diamond-coated sintered alloy of the present invention can form a high-quality diamond coating more easily than a conventional diamond-coated sintered alloy or a diamond-coated sintered alloy outside the present invention. This has the effect of increasing the adhesion between the film and the substrate and significantly improving the peeling resistance of the film.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-88742 (JP, A) JP-A-2-1533071 (JP, A) JP-A-2-54768 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C23C 16/26-16/27 B23B 27/00 B23P 15/28 C22C 1/05 C23C 14/06 C30B 29/04

Claims (3)

(57) [Claims] 1. One or more hard phases of at least one of carbides, nitrides and mutual solid solutions of metals of groups 4a, 5a and 6a of the periodic table, with the balance being Co and / or N
In a diamond-coated sintered alloy obtained by forming a film of diamond and / or diamond-like carbon on the surface of a base material of a sintered alloy composed of a binder phase containing i as a main component, the interphase compound is contained in the binder phase. The intermetallic compound contains Co and / or Ni and Al and / or Si, and the intermetallic compound to the binder phase has a volume ratio of 5%.
A high adhesion diamond-coated sintered alloy characterized by containing 0% or more. 2. The high-adhesion diamond-coated sintered alloy according to claim 1, wherein the hard phase comprises tungsten carbide as a main component. 3. The high-adhesion diamond-coated sintered alloy according to claim 1 or 2, which is used as a wear-resistant tool or a cutting tool.