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A method of depositing a CVD diamond coating on a polycrystalline diamond compact

A technology of polycrystalline diamond and diamond coating, applied in metal material coating process, coating, gaseous chemical plating, etc., can solve the problems of residual stress, poor thermal stability, failure, etc., and achieve the effect of improving the nucleation rate

Inactive Publication Date: 2019-05-14
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The main form of damage to the polycrystalline diamond compact is the shedding and damage of the diamond layer. The reason should be attributed to the difference in physical and chemical properties between the diamond layer and the cemented carbide, as well as between the diamond and the binder inside the diamond layer. Poor stability
The temperature changes during the processing and working process of the composite sheet will generate residual stress inside the composite sheet, and once the force is applied, it will lead to failure

Method used

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  • A method of depositing a CVD diamond coating on a polycrystalline diamond compact
  • A method of depositing a CVD diamond coating on a polycrystalline diamond compact
  • A method of depositing a CVD diamond coating on a polycrystalline diamond compact

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Experimental program
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Effect test

Embodiment 1

[0035] An experimental process method for depositing a CVD diamond coating on a polycrystalline diamond composite sheet substrate, the steps are as follows:

[0036]The first step is to mechanically polish the polycrystalline diamond composite sheet, then put it into a 15% HNO3 solution, and corrode it for 10 to 20 minutes. The pickling process can make the cobalt in the surface layer chemically react with the acid solution to form a stable compound. At the same time, a part of the diamond particles are exposed, and the effect of homoepitaxial growth is achieved during the deposition process. Then put it into acetone or ethanol suspension containing diamond micropowder, clean it with ultrasonic vibration for 30 minutes, and dry it; the ultrasonic cleaning process can not only clean the surface of the substrate more thoroughly, but also plant the dispersed diamond micropowder on the substrate to improve the quality of the diamond. The nucleation rate of the film.

[0037] In ...

Embodiment 2

[0042] A method for depositing a CVD diamond coating on a polycrystalline diamond compact, comprising the following steps:

[0043] (1) Take the polycrystalline diamond composite sheet formed by hot pressing of diamond powder and binder Co and grind it mechanically, put 15% HNO 3 Corrosion in the solution for 10 minutes, then placed in acetone or ethanol suspension containing diamond micropowder, ultrasonically oscillating for 20 minutes, and dried to obtain a pretreated polycrystalline diamond composite sheet;

[0044] (2) Take the pretreated polycrystalline diamond composite sheet and put it into a microwave plasma chemical vapor deposition equipment. Under vacuum conditions, feed hydrogen until the reaction system is a 100% hydrogen atmosphere, and keep the pressure in the reaction chamber at about 0.8Kpa , so that the surface of the polycrystalline diamond compact is etched by hydrogen;

[0045] (3) Reintroduction into CH 4 gas, keep CH 4 and H 2 The volume ratio is 1:...

Embodiment 3

[0047] A method for depositing a CVD diamond coating on a polycrystalline diamond compact, comprising the following steps:

[0048] (1) Take the polycrystalline diamond composite sheet formed by hot pressing of diamond powder and binder Co and grind it mechanically, put 15% HNO 3 In the solution, corrode for 20 minutes, then put it into acetone or ethanol suspension containing diamond micropowder, clean it with ultrasonic vibration for 40 minutes, and dry it to obtain a pretreated polycrystalline diamond composite sheet;

[0049] (2) Take the pretreated polycrystalline diamond composite sheet and put it into a microwave plasma chemical vapor deposition equipment. Under vacuum conditions, feed hydrogen gas until the reaction system is a 100% hydrogen atmosphere, and keep the air pressure in the reaction chamber at about 1.5Kpa , so that the surface of the polycrystalline diamond compact is etched by hydrogen;

[0050] (3) Reintroduction into CH 4 gas, keep CH 4 and H 2 The ...

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Abstract

The invention relates to a method for depositing a CVD diamond coating on a polycrystalline diamond composite sheet. The method comprises the following steps of: (1) taking the polycrystalline diamond composite sheet to mechanically grind and pickle, performing ultrasonic oscillating and cleaning, and drying to obtain a pre-treated polycrystalline diamond composite sheet substrate; (2) taking and putting the pre-treated polycrystalline diamond composite sheet substrate into microwave plasma chemical vapor deposition equipment, introducing nitrogen gas under a vacuum condition until a reaction system is 100% hydrogen gas atmosphere, and etching the surface of the polycrystalline diamond composite sheet by hydrogen gas; and (3) introducing CH4 gas, depositing the CVD diamond coating, and cooling to the room temperature, thereby completing deposition of the CVD diamond coating; and introducing argon gas while introducing CH4 gas. Compared with the prior art, the method has the advantages that bonding strength between the CVD diamond coating and a film substrate interface of the polycrystalline diamond composite sheet is high, and the problems such as tool failure caused by thermal-cracking cracks generated by thermal expansion and cold contraction as well as oxidization of a binding agent are avoided.

Description

technical field [0001] The invention relates to the preparation of superhard materials, in particular to a method for depositing a CVD diamond coating on a polycrystalline diamond composite sheet. Background technique [0002] The diamond coating can be deposited on the cemented carbide substrate by chemical vapor deposition through microwave plasma equipment. The researchers have obtained better process parameters through a certain scale of experiments, and achieved relatively good control over temperature, pressure and gas concentration. good research. However, by adjusting the process parameters, the quality of the deposited coating is often controlled to a certain extent. In the test with cemented carbide as the substrate, the bonding performance between the diamond coating and the substrate is often poor, and the coating is easy to fall off when the sample is taken out at the end of the reaction. The fundamental reason is that the thermal expansion coefficients betwee...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C16/27
CPCC23C16/274C23C16/276
Inventor 简小刚黄卓
Owner TONGJI UNIV