JPS6152363A - Method for depositing and forming artificial diamond film on surface of cermet member - Google Patents

Abstract

PURPOSE:To deposite and form a film having fine structure and excellent adhesiveness by a subjecting the surface of a cermet member to an etching treatment prior to the deposition and formation of an artificial diamond film on the surface of said member to remove the bond phase. CONSTITUTION:A geseous mixture reactive by heating composed essentially of hydrocarbon and hydrogen is activated by plasma discharge using a thermion radiating material and high frequency or plasma discharge by microwaves. The heated cermet member is placed in the flow of such reactive gaseous mixture and the artificial diamond film is deposited and formed on the surface thereof. The surface of the cermet member is subjected to the etching treatment to remove the bond phase on the member surface as the pretreatment prior to the formation of such film, by which the initially deposited crystal nuclei of diamond are increased. The diamond film which obviates thoroughly the exfoliation, etc. is thus formed on the cermet member.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention aims to increase the number of diamond crystal nuclei that precipitate on the surface of the cermet member in the initial stage of the reaction when forming an artificial diamond film on the surface of the cermet member. The present invention relates to a method for depositing and forming an artificial diamond film having a fine structure and excellent adhesion.

[Conventional technology]

Generally, the dispersed phase is mainly 4a of the periodic table.

5a and 6a group metals, and one or more of 3i carbides, nitrides, carbonitrides, and borides, while the binder phase mainly consisted of one or more iron group metals. Cermet members are known. It is also known to deposit and form an artificial diamond film on the surface of this cermet member, and a number of methods have been proposed for this method, among which is a method of heating and activating the reaction mixture gas. (a) Thermionic emitting material, (b) Plasma discharge by high frequency, (C) Plasma discharge by microwave, and the above (a) to (
A method that adopts either C) is attracting attention as a typical method.

That is, the above method (a), as shown in the schematic cross-sectional view in FIG. A reaction mixture gas composed of hydrogen and hydrogen is caused to flow downward through a filament 3 made of, for example, metal tungsten as a thermionic emission material and a cermet member 5 supported on a base plate 4, during which time the atmospheric pressure in the reaction vessel 1 is maintained. 0.1-3
Hold the filament 3 at 15 torr while holding it at 15 torr.
00 to 2500°C to activate the reaction mixture gas and heat the surface of the cermet member 5 disposed below a predetermined distance to a temperature within the range of 300 to 1300°C, and in this state This is a method of depositing and forming an artificial diamond film on the surface of the cermet member 50 by performing a time reaction, for example, as disclosed in Japanese Patent Application Laid-Open No. 58-91100.
The method described in the above publication corresponds to this method.

In addition, as shown in the schematic cross-sectional view in FIG. A reaction mixture gas mainly composed of hydrocarbons and hydrogen is introduced from the mixed gas introduction pipe 2, and exhausted from the other side of the reaction vessel 1. During this time, the atmospheric pressure inside the reaction vessel 1 is maintained at several torr to several tens of torr. At the same time, conditions such as a frequency of 13.56 MHz and a power output of 500 W are added to the high frequency coil 6 provided at the central outer circumference of the reaction vessel 1 to generate a plasma discharge around the cermet member 5 in the reaction vessel 1. A method for depositing and forming an artificial diamond film on the surface of a cermet member by inducing a plasma discharge, heating the reaction mixture gas and raising the surface temperature of the cermet member, and allowing the reaction to occur in this state for a predetermined period of time. For example, JP-A-58-1351
The method described in Publication No. 17 is a method corresponding to this.

Furthermore, as similarly shown in the schematic cross-sectional view in FIG. A reaction mixture gas mainly composed of hydrocarbons and hydrogen is introduced from the mixed gas introduction pipe 2, and exhausted from the bottom of the reaction vessel 1. During this time, the atmospheric pressure inside the reaction vessel is reduced to 0.1.
~300 torr, and further supplied through a waveguide 7 provided at the central outer periphery of the reaction vessel 1, for example, 2 torr.
The 450 MHz microwave is adjusted by the plasma adjustment plunger 8, and the cermet member 5 in the reaction vessel 1 is heated.
A plasma discharge is generated around the cermet member, and this plasma discharge heats and activates the reaction mixture gas and increases the surface temperature of the cermet member. In this state, a reaction between a predetermined value of I is carried out, and artificial diamond is formed on the surface of the cermet member. This is a method of depositing and forming a film, and for example, the method described in JP-A-58-110494 is a method corresponding to this method.

[Problem that the invention seeks to solve]

However, in all of these artificial diamond film precipitation formation methods, the number of diamond crystal nuclei that precipitate on the surface of the cermet member at the initial stage of the reaction is small, whereas the artificial diamond grows around these crystal nuclei and forms a film. Therefore, the artificial diamond film formed by precipitation had a coarse structure and poor adhesion to the surface of the cermet member.

[Means for solving problems]

Therefore, from the above-mentioned viewpoint, the present inventors conducted research to deposit and form an artificial diamond film with a fine structure and excellent sealability on the surface of a cermet member. Prior to depositing and forming the artificial diamond film, as a pretreatment, the surface of the cermet member is etched to remove the binder phase on the surface of the cermet member, thereby increasing the surface area ratio of the dispersed phase, Then, when an artificial diamond film is precipitated and formed by a normal method in this state, the formation of the artificial diamond film is delayed because the dispersed phase with the increased surface area ratio acts to significantly increase the number of diamond crystal nuclei precipitated in the early stage of the reaction. They found that the resulting artificial diamond film has a fine structure and excellent adhesion.

Therefore, this invention was made based on the above knowledge, and the main components are hydrocarbons and hydrogen and activated by a thermionic emitting material, plasma discharge by high frequency, plasma discharge by microwave, etc. When depositing and forming an artificial diamond film on the surface of the cermet member by placing the heated cermet member in a flow of heated reaction mixture gas, the surface of the cermet member is etched as a pretreatment. By removing the binder phase constituting this, the surface of the cermet member on which the artificial diamond film is formed is mainly composed of the dispersed phase, and by depositing and forming the artificial diamond film on the surface of the cermet member in this state. This method is characterized by increasing the number of diamond crystal nuclei precipitated at the initial stage of the reaction.

[Example and its effects]

Next, the method of the present invention will be specifically explained using examples.

Example 1 A cutting chip having a composition of 611% Co, WC, and the remainder of unavoidable impurities was prepared as a cermet member, and the cutting chip was immersed in a 7% HNO3 solution for 3 hours to etch its surface. The binder phase constituting the cutting tip was removed, and the surface of the cutting tip was made to consist mainly of a dispersed phase made of WC.

Then, using the apparatus shown in Figure 1, a reaction vessel (1) was prepared.
: Made of quartz with an outer diameter of 50 trynφ, reaction mixture gas composition: including volume ratio, CHa/l-12=1
/100゜Metal tungsten filament (3) and cutting tip (
5) Distance from surface: 30m.

Atmospheric pressure: 20 torr.

Heating temperature of filament (3): 2000°C.

Heating temperature of cutting tip (5) by filament is near 0
0℃.

Processing time: 2 hours.

Artificial diamond precipitation formation treatment was performed on the surface of the cutting tip after the above etching treatment under the following conditions.

As a result, artificial diamond was precipitated on the surface of the cutting tip which had been subjected to the etching treatment as the pre-treatment, accounting for 60% of the surface area.

On the other hand, for the purpose of comparison, an artificial diamond precipitation formation process was performed under the same conditions except that no etching process was performed, and only 30% of the area ratio of artificial diamond was precipitated.

From these results, it is clear that by etching the surface of the cutting tip in advance, the number of diamond crystal nuclei can be increased at the initial stage of the reaction.

Furthermore, when artificial diamond precipitation formation treatment was performed for 6 hours under the same conditions, the surface of the cutting tip that had been etched as a pretreatment was made fine with an average crystal grain size of 2 μm and an average layer thickness of 3 μm. In contrast, the artificial diamond film formed on the surface of the cutting tip without etching treatment had almost the same layer thickness, but the average crystal grain size was 4 μm. It was rough.

Further, for both of the cutting chips obtained as a result, the workpiece material: Affi-12% by weight 81 alloy.

Cutting speed: 5001rL/min.

Feed: 0.1mm/rev.

Depth of cut: 1m.

Cutting time: 30m1n.

When we conducted a continuous cutting test under the following conditions and observed the state of the cutting edge after the test, we found that the cutting tip that had been etched was completely normal, with no wear or chipping. Although the cutting tip that was not subjected to this process showed no wear, peeling phenomenon was observed, and it was confirmed that the adhesion of the artificial diamond film was significantly improved by performing the etching process as a pretreatment.

Example 2 As a cermet member, TiC: 10%, C,o:
10%, WC and unavoidable impurities: composition consisting of the remainder (
Prepare a cutting chip with a loss of % or more, and perform an etching process on this cutting chip by immersing it in a 10% HCffi solution for 6 hours to remove the bonding phase on its surface and remove TiC and WCffi. It consists of a dispersed phase mainly composed of.

Next, using the apparatus shown in FIG. 2, the reaction vessel (1)
: A quartz tube with an outer diameter of 4° and φ.

Reaction mixture gas composition: in volume ratio, CH4/H2=, 2/
100° atmospheric pressure crab 10 torr.

Application conditions to high frequency coil (6): Frequency 13.56M
Hz, power + 1 KW.

Processing time: 2 hours.

When an artificial diamond precipitation formation process was carried out under the following conditions, artificial diamond was precipitated on the surface of the cutting tip at an area ratio of 75%.

On the other hand, for the purpose of comparison, artificial diamond was deposited on the surface of a cutting tip that was subjected to artificial diamond precipitation forming treatment under the same conditions except that no etching treatment was performed. there were.

Example 3 As a cermet member, Ni: 15%, Mo: 10%,
A cutting tip having a composition (more than 25% suspended) consisting of WC: 25%, TiC and unavoidable impurities: the remainder,
This cutting chip was subjected to etching treatment by immersing it in a 5% nitric acid solution for 6 hours to remove N1 and Mo, which are binder phase forming components on the surface, and thereby transform the surface of the cutting chip into a dispersion mainly composed of WC and TiC. It is assumed to consist of phases.

Next, using the apparatus shown in FIG. 3, the reaction vessel (1)
: A quartz tube with an outer diameter of 5° and φ.

Reaction mixture gas composition: CH4/H2 = 2/1 in volume ratio
00° atmospheric pressure crab 20 torr.

Microwave: 2450MHz (output 300W) processing time = 2 hours.

When artificial diamond precipitation was performed under the following conditions, artificial diamond was precipitated on the surface of the cutting tip at an area ratio of 72%, which indicates that diamond crystal nuclei were precipitated at the initial stage of the reaction. This indicates a large amount.

On the other hand, for the purpose of comparison, on the surface of a cutting tip that was subjected to artificial diamond precipitation formation treatment under the same conditions except that no etching treatment was performed, artificial diamond precipitation was observed only in an area ratio of 40%. This shows that the precipitation of diamond crystal nuclei is relatively smaller than in the case where etching treatment is performed.

As described above, according to the method of the present invention, prior to depositing and forming an artificial diamond film on the surface of a cermet member, the surface is etched to remove the binder phase constituting the cermet member, and substantially By making the surface of the cermet component consist of a dispersed phase, it is possible to significantly increase the precipitation formation rate of diamond crystal nuclei at the initial stage of the reaction, and the artificial diamond film formed thereby has a fine structure that is right-centered. At the same time, it has excellent adhesion, and industrially useful effects such as no peeling during practical use can be obtained.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are all schematic cross-sectional views showing an apparatus for depositing an artificial diamond film. 1... Reaction container, 2... Reaction mixed gas introduction pipe. 3...Filament as a thermionic emitting material. 4... Base plate, 5... Cermet member. 6...High frequency coil, 7... Waveguide. Applicant Mitsubishi Metals Co., Ltd. and 1 other agent Tomi 1) Kazuo and 1 other person Figure 2 Figure 3

Claims (1)

[Claims] The main components are hydrocarbons and hydrogen, and thermionic emitting material,
An artificial diamond film is deposited and formed on the surface of the cermet member by placing the heated cermet member in a flow of a heated reaction mixture gas activated by high frequency plasma discharge or microwave plasma discharge. The method is characterized in that the surface of the cermet member is etched as a pre-treatment to remove the binder phase on the surface of the cermet member, thereby increasing the number of initially precipitated crystal nuclei of diamond. A method of depositing and forming an artificial diamond film on the surface of a cermet member.