JPS60100660A - Surface-coated hard material - Google Patents

Abstract

PURPOSE:To form a hard coating layer having excellent adhesion strength to a base material by depositing physically a hard compd. of specific metals by evaporation on the surface of the base material for a cutting tool, etc. with Co, etc. as a binder. CONSTITUTION:A thin hard coating layer is formed on the surface of a base material consisting of a sintered hard alloy or ceramics in the manufacture of a cutting tool to extend the service life of the cutting tool. The surface of the base material is first cleaned then the hard layer is deposited to 0.1-0.5mum by a physical vapor deposition method such as an ion plating method, sputtering method or the like. Hard material such as WC, TaC, NbC, TiC or TiN is used for the hard layer and Co, Fe, Ni, Cr, W or Mo and above all Co is used as a binder at 1-30%. The hard coating layer which has high adhesion to the base material of the cutting tool and does not peel during use is formed and the service life of the cutting tool is extended.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention has a high adhesion strength between a base material and a hard coating layer that covers the entire surface of the base material, so that when used in cutting tools etc., the service life thereof is shortened. The present invention relates to a long surface-coated hard material, and more specifically, to a hard material manufactured by applying a physical vapor deposition method (PVD method).

[Technical background of the invention and its problems]

Conventionally, in the manufacture of hard materials such as cutting tools, the surface of various cemented carbide or ceramic base materials has been coated with a thin hard coating layer.

Recently, chemical vapor deposition (CV) methods have been used to form hard coating layers.
Low-temperature coating treatment is possible using the physical vapor deposition method (PVD method) than using the PVD method (method D).
This method has attracted wide attention because it has the advantage that the mechanical strength of the material on which the coating layer is formed does not decrease comparatively.

However, according to the PVD method, the adhesion strength between the base material and the coating layer is extremely low, so that a part of the coating layer may peel off in cutting tools and the like. Therefore, the application of the PVD method has been limited by the intended use of the material.

In order to solve all the above problems by applying the PVD method,
A method has been proposed in which a thin layer of active titanium metal is formed as an adhesive layer on the surface of a base material, and a hard coating layer is formed on the titanium layer.

However, this method requires one more coating process, and since the titanium layer is a soft layer, it is not suitable for application to tools that are used under harsh operating conditions where high temperatures or high shear forces are applied. It includes issues that need to be solved, such as:

[Purpose of the invention]

Although the present invention applies the PVD method during manufacturing, the adhesive strength between the base material and the hard coating layer is high, and therefore,
The object of the present invention is to provide a surface-coated hard material that does not cause peeling of the coating layer even under severe usage conditions.

[Summary of the invention]

The present inventors investigated the reason why the adhesion strength of the coating layer to the base material is greater in the case of the CVD method than in the case of the PVD method, and found that in the former case, the interface between the base material and the coating layer is It was found that one type of diffusion layer is generated and this diffusion layer functions as a bonding layer between the base material and the coating layer. Therefore, even if the PVD method is carried out at a lower temperature than the CVD method, we got the idea that the adhesive strength between the base material and the coating layer would be improved if the entire diffusion layer as described above could be generated.
As a result of extensive research based on this idea, we surprisingly found that when applying the PVD method, if the entire surface of the base material is thoroughly cleaned, even under normal PVD conditions, the gap between the base material and the coating layer can be removed. The present invention was completed based on the discovery that one kind of diffusion layer can be formed in the following manner.

That is, the surface-coated hard material of the present invention is
At least one hard substance selected from the group of carbides, nitrides, oxides, borides, silicides, and mutual solid solutions of at least one element belonging to the fl//a, Va, , M, groups. Phase components: iron (Fe), nickel (Ni), cobalt (CO), chromium (Cr),
A hard material coated with a hard coating layer by a PVP method, the hard material comprising at least one binder phase component selected from the group of molybdenum (Mo) and tungsten (W). It is characterized in that a diffusion layer is formed on the surface of the base material at the interface with the material.

In the present invention, the substrate coated with the hard coating layer is a sintered alloy consisting of a hard phase component and a binder phase component. As hard layer components, 'pi;'a, Va' of the periodic table are used.

・, one or two of carbides, nitrides, oxides, borides, silicides, and mutual solid solutions of elements belonging to group a
More than a species. Preferably Tic, TIN.

ZrC, VCt TaCt NbC, Mo2C* Cr
3C2+ WC+TIB r TaSi r TiO,
Zr0z, etc. In particular, at least one of 2 2 TIClTIN, TaC2NbCIWC
When seeds are contained, it is advantageous because it facilitates the formation of a diffusion layer, which will be described later.

Bonded phase components include Fe, Nie Cor
It is any one or more of Cr tMo and H, preferably Co.

The base material can be manufactured by mixing the above-mentioned hard phase component powder and binder phase component powder in a predetermined ratio, and molding and sintering the mixture by a conventional method. At this time, the blending ratio of the binder phase components is
Usually 1 to 30% by weight or more.

A hard coating layer is formed on the surface of this base material by a PVD method. The material constituting the hard coating layer is at least one layer of carbides, nitrides, borides, and mutual solid solutions or mixtures thereof of elements belonging to group N=a of the periodic table, or aluminum oxide (A1203). Become. For example, Tic, TIN, TlB2; ZrCe ZrN
, ZrB,” HfC, HfN, HfB2
;1 5 TiC0, TiN0, TiCN0% (TI
Zr)(-p(TiHf)CpA1203 etc. stimulate the diffusion of interstitial elements that are naturally present in the base material, making it easy to form a complete diffusion layer on the surface of the base material at the interface between the hard coating layer and the base material. Make it easier.

The coating layer may be a single layer of each of the above-mentioned materials, but it may also be a composite layer formed by sequentially laminating two or more of these gold layers.

The hard material of the present invention as described above is manufactured as follows. The most important feature of the manufacturing method is that the surface of the base material is thoroughly cleaned to completely remove impurities adhering to the surface or oxides of the binder phase component of the base material, basically by the method described below. The purpose of this method is to apply the PVD method in a clean atmosphere.

First, the surface of the substrate is sufficiently washed with a nonionic surfactant to completely remove dirt, oil, etc. from the surface. When cleaning, it is effective to perform a brushing process to the extent that the surface is not damaged. The surfactant used must be nonionic; cationic or anionic surfactants should be avoided because these ions may remain on the surface of the substrate.

Then, the surface of the substrate is washed in an gold acid solution. At this time, it is effective to apply ultrasonic cleaning. As the acid solution, hydrochloric acid, dilute sulfuric acid, etc. are preferable, and the pH thereof varies depending on the base material components and the surface condition of the base material, such as a sintered surface and a ground or polished surface. ~G
It is preferable that Depending on the contamination state of the surface of the substrate, it may be necessary to further modify the type of acid solution, cleaning time, temperature, or pH value that are required for acid solution cleaning. During this process, if the binder phase component present on the surface of the substrate is oxidized and contaminated, it is dissolved and removed.

Thereafter, ultrasonic cleaning is performed in pure water to completely remove the activator, acid solution, etc. remaining on the surface of the substrate through the two steps described above.

The pure water used is one that has been treated with an ion exchange resin to completely remove trace amounts of gold, a metal component in the water.

Thus, the surface of the substrate becomes a surface composed only of the hard phase component and the binder phase component.

Next, the base material is placed in an all-organic solvent, subjected to ultrasonic cleaning, and water is replaced with an organic solvent. As the organic solvent, a volatile one is used, and specifically, methyl alcohol, ethyl alcohol, acetone, ether, etc. are preferred.

Finally, a hard coating layer for all PVD methods is formed on the surface of the resulting clean substrate.

The PVD method to be applied may be a commonly used method and is not particularly limited, and for example, an ion blasting method, a sputtering method, a coating method using a gas reaction in plasma, etc. can be applied. Although the temperature varies depending on the type of coating layer material, it is usually desirably about 200 to 700°C.

At this time, care should be taken not to contaminate the entire surface of the substrate, either when setting the substrate in the PVD apparatus or performing the PVD operation. For example, when setting a substrate in an apparatus, it is preferable to perform the operation in dry air with low humidity.

When a hard coating layer is formed by the PVD method in this manner, a type of diffusion layer is generated at the interface between the base material and the coating layer. Specifically, over a certain depth on the surface of the base material, a layer of a compound or a layer of a non-stoichiometric compound in which nonmetallic components (e.g., C, N, B) in the hard phase components constituting the base material are reduced. become. Conversely,
The non-metallic component on the surface of the base material diffuses toward the coating layer,
What is the base material?

A heterogeneous diffusion layer with a thickness of 0.05 to 1 μm is produced.

Although the details are unknown, it is thought that the presence of this diffusion layer improves the adhesive strength between the base material and the coating layer, especially when the thickness of this diffusion layer is 0.1 to 0.5 μm. preferable.

[Embodiments of the invention]

Example 1 5DCN4aZTN for milling, made of a material consisting of 90% by weight of hard phase component WC and 10% by weight of binder phase component Co.
The surface of the mold grinding tip was subjected to one automatic brushing treatment in a shower of a 5% aqueous solution of neutral detergent.

The chips were then ultrasonically cleaned in a 16-ml hydrochloric acid aqueous solution.
The overflowing pure water was sequentially passed through four ultrasonic cleaners. Thereafter, it was passed through three baths of an ethyl alcohol ultrasonic cleaner, and further passed through three baths of an acetone ultrasonic cleaner.

Then, after passing through two tanks of an ultrasonic cleaner using fluorocarbons, it was finally dried using fluorocarbons at 60°C. The cleaning time for the substrate in each tank was 7 minutes.

The chip was attached to a thoroughly cleaned stainless steel jig in dry air with a humidity of 20%, and set in a thoroughly cleaned ion blating device.

After the inside of the apparatus was evacuated to f 10-5 T, orr, the chip was gradually heated to 500° C. while maintaining the vacuum in the furnace at a higher vacuum than f 10-’ Torr.

Next, the chip surface is bombarded with 99.999999% purity argon gas for 40 minutes, and then all nitrogen gas is introduced to reduce the nitrogen gas partial pressure in the device! TiN was PVDed using a conventional method at io and 13 Pa. The precipitation rate of the hard coating layer at this time was 1.3 x 10''μm/sec.
The thickness of the hard coating layer was approximately 2 μm.

The base material of the chip is 72% by weight of WC and 10% by weight of Tic.
, the coating layer was a sintered alloy containing 10% by weight of TaC and 8% by weight of Co, the temperature of the coating layer was 50°C, the acetylene partial pressure was Q,
A TaC layer with a thickness of about 1 μm formed with 10 P&, a temperature of 650° C., and an oxygen gas partial pressure of 4×10 −2 Pa.

AI! AI with a thickness of approximately 1 μm formed by electron beam evaporation! 203 were laminated in this order,
A hard material was produced in the same manner as in Example 1 for all wires.

Comparative Example 1 The substrate was subjected to ultrasonic cleaning using a neutral detergent, and then pH
After ultrasonic cleaning in the sulfuric acid aqueous solution of No. 5, the samples were sequentially passed through two overflowing ultrasonic cleaner tanks with pure water. Thereafter, it was passed through a water draining Freon tank and finally dried at 60°C. All other hard materials were manufactured in the same manner as in Example 1.

Comparative Example 2 In Comparative Example 1, after bombarding the surface of the substrate with argon gas, a titanium layer of 0.1 μm was first formed on the surface, and then a titanium layer with a thickness of 1.1 μm was formed on the surface under conditions of a nitrogen gas partial pressure Q and 13 Pa. It was coated with 9 μm TiN'i. The deposition rate of the coating layer was 1.3 × 10−3 μffl/m@e.

With the above four types of tips, stainless steel (5TJS)
304) block was completely milled.

The cutting conditions were a cutting speed of 148 m/mln, a depth of cut of 2 m, a feed rate of 0.3 mu/tooth, and a cutting time of 30 minutes.

The percentage of peeled surface coating layer in the area of the chip rake face in contact with the material to be stiffened was measured. Example 1 3.2
%, 1.8 inches for Example 2, 78 inches for Comparative Example 1,
The weight of Comparative Example 2 was 49.

In addition, Example 1. When the chip of Example 2 was cut and its cross-sectional state was observed under a microscope, it was found that in both cases, at the interface between the base material and the coating layer, there was a thickness of about 0.15 μm on the base material side (example work);
A layer with a different structure from that of the base material was observed at a depth of about 0.25 μm (Example 2).

〔Effect of the invention〕

As is clear from the above explanation, the hard material of the present invention has a high adhesive strength between the base material and the hard coating layer, and therefore the coating layer will not peel off even when used in cutting tools, and therefore the service life will be shortened. become longer.

Matrap, in its manufacturing method, the surface of the base material is cleaned,
Others can apply conventional PVD methods to produce the above-mentioned useful materials, the industrial effectiveness of which is outstanding.

Claims (1)

[Claims] 1. IVa) -Va selected from the group of carbides, nitrides, oxides, borides, silicides, and mutual solid solutions of at least 11 elements belonging to group Va of the periodic table. a hard phase component of at least 11 and iron, nickel, cobalt, chromium, molybdenum, and tungsten
A hard material in which the surface of a base material comprising at least one binder phase component selected from the group is coated with a hard coating layer by a physical vapor deposition method (PVD method), wherein the hard coating layer and the left-handed A surface-coated hard material characterized in that a diffusion layer is entirely formed on the surface of the base material at the interface. 2. Claim 1, wherein the base material contains at least one hard phase component selected from the group of tungsten carbide, tantalum carbide, niobium carbide, titanium carbide, and titanium nitride.
The surface-coated hard material described in Section 1. 3. A patent claim in which the hard coating layer is at least one layer selected from the group of carbides, nitrides, borides, and mutual solid solutions or mixtures thereof of elements belonging to the dlVa group of the periodic law, or aluminum oxide. The surface-coated hard material according to item 1. 4. The surface-coated hard material according to claim 1, wherein the diffusion layer is made of a compound or a non-stoichiometric compound with a thickness of 01 to 05 μm.