JPS62162683A - Coated silicon nitride product - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a highly efficient cutting tool capable of cutting at high speeds.

[Prior art]

Because silicon nitride sintered bodies have extremely high toughness, they cannot be used as conventional ceramic sintered cutting tool materials, such as Aj go
It was highly anticipated as a dream ceramic tool material that is significantly more reliable than s/TiC sintered bodies (hereinafter referred to as black ceramics).

However, silicon nitride sintered body has a hardness of 1500 to 1700 kg/am on the Vikers hardness, which is softer than black ceramic, so when it is actually used for high-speed cutting of castings, its wear resistance is lower than that of conventional materials. Compared to the black cera that has been used, its use has been extremely limited due to its scarcity.

Therefore, as shown in Japanese Patent Publication No. 59-13475, coated silicon nitride parts are made using this tough silicon nitride sintered body as a base material and coating the surface with a thin film of A1*Os that is highly wear resistant. Proposed.

[Problem that the invention seeks to solve]

It is true that conventional coated silicon nitride parts have greatly improved wear resistance, which is the biggest drawback of silicon nitride cutting tools. However, the manufacturing method generally uses chemical vapor deposition, which is a method for manufacturing coated cemented carbide. In coated cemented carbide, the bond between the base material and the coating film (often TiC is often used) is chemically bonded, so the adhesive strength is extremely strong. For silicon parts, silicon nitride sintered bodies and silicon nitride sintered bodies are coated at a coating temperature of about 120°C by chemical vapor deposition. Since there is almost no chemical bonding between the film and the film, its adhesive strength cannot be said to be sufficient. Therefore, in conventional coated silicon nitride parts, AZz
The limit for the thickness of Os is 3 μm, and if it is thicker than that, the UzOs film will peel off at an early stage during actual cutting, which is a major drawback.

Therefore u80. There were naturally limits to the improvement of wear resistance of silicon nitride cutting tools by coating them with silicon nitride.

The present invention aims to improve the adhesive strength between the base material and the coating film of this rgI silicon nitride component.

[Disclosure of the invention]

In order to improve the adhesive strength between the base material and coating film of coated silicon nitride parts, it is desirable to chemically bond between the base material and the coating film. The most common method is to increase the temperature. However, equipment for coating at a high temperature of 1000° C. or higher must be extremely complicated and is extremely difficult from an industrial perspective. Therefore, as a result of various studies, the inventor discovered that when coating UtOx, Si, which is the main component of silicon nitride, coexists in the coating film so that the coating film and the base material are chemically bonded. We thought that this would improve the adhesive strength.

In addition, regarding 5ill in Alt (h), the weight ratio is 0.
If it is less than 0.01%, the effect is observed, but if it is less than 10%, the hardness of the coating film itself is insufficient, so that the wear resistance as a cutting tool is insufficient, which is not preferable. Further, if the thickness of the coating film is less than 1 μm, the effect of improving wear resistance is difficult to be recognized, and if it is more than 30 μm, the coating film may peel off during cutting, which is not preferable.

Note that the adhesive strength is further improved when an intermediate film of 0, 1-10 μm consisting of Si and/or Ti carbide and/or nitride is present between the Si-containing utosp/J and the base material. I also understood. This intermediate film is 0.1μ
Below, the effect is observed, but if it is <10μ or more, the coating film tends to peel off, which is not preferable.

This will be explained in detail in Examples below.

Example l 5isN485 weight It 9A, Ydh 5% by weight
1000 pieces of 5iJn sintered bodies (model number 5NGN12040B) consisting of 10% by weight of UTC were held in a normal chemical vapor deposition equipment and heated to 1000°C.
.

Remaining H! The following gas was flowed at 20 Torr for 10 hours. After cooling and examining it, it was about 5μ U20. A membrane (found to contain 2.3% by weight Sl by Auger spectroscopy) was coated. This sample was designated as No. 8, and the same base material was used under the same conditions (but 0.5% by volume of 5iCj).

B was coated with about 5μ of U, O, without the addition of
For comparison, a specimen coated with 1 μm of A7 and O in the same process as B was used, and a specimen not coated with C1 was labeled D, and a cutting test was conducted under the following conditions.

Workpiece material: Fe12 Cutting speed: 600m/min Feed rate: 0.36mm/rev Depth of cut: 2.0mm Holder: FNIIR-44A Cutting agent: Water-soluble Use A has flank wear of 0.28mm after cutting for 30 minutes. On the other hand, for B, the coating peeled off after 3 minutes and 14 seconds of cutting, and the flank wear reached 0.46 mm during 5 minutes of cutting, making it impossible to cut. C was cut for 10 minutes and flank wear was 0.38 mm, and D was cut for 5 minutes and flank wear was 0.64 n+m.

Example 2 Sl, N, 75 weight 1i%, TiN 10 weight fft
%, A720310 heavy four.

Sintered body consisting of y, o, s weight% Model number 5NGN 12
0408) as the base material, S
A7,0. A cutting test was conducted under the same conditions as in Example 1.

Table 1 shows the Sl content (■) and the results of the cutting test.

Table 1 Example 3 Using the same base material as in Example 2, various coated silicon nitride parts were created. In order to investigate the cutting performance, a cutting test was conducted under the following conditions.

Work material: Fe12 Cutting speed: 800m/sin Feed: 0.40mm/rev depth of cut i
1, 5 mm Holder: F NIIR-44A Cutting material: Not used Cutting time: 3 minutes The structure of the resulting coating film is shown in Table 2.

Table-2 Described as genuine flank wear 【Effect of the invention〕 As mentioned above, AI and O of coated silicon nitride parts.

By adding Si to the film, the base material and the yI
It is possible to improve the adhesive strength with the film.

Claims (2)

[Claims] (1) A coated silicon nitride component in which the base material is a sintered body mainly composed of silicon nitride, and the surface thereof is coated with a ceramic thin film of 1 to 30μ, in which the ceramic thin film is composed of Al and Si.
oxide, and the weight ratio of Si is 0.01 to 10.
% coated silicon nitride parts. (2) In the coated silicon nitride component according to claim 1, between the silicon nitride sintered body and the ceramic thin film, 0.1 to 10μ of carbide and/or nitride of Si and/or Ti is provided. A coated silicon nitride component characterized by the presence of an interlayer film of.