Polycrystalline cubic boron nitride composite sheet and preparation method thereof

Abstract

The invention provides a polycrystalline cubic boron nitride composite sheet and a preparation method thereof. According to the polycrystalline cubic boron nitride composite sheet and the preparation method thereof, used titanium-transition metal solid solution boride ceramic has the advantages of high melting point, high hardness, excellent corrosion resistance and oxidation resistance, good electrical conductivity and thermal conductivity, and a thermal expansion coefficient similar to that of cubic boron nitride, the titanium-transition metal solid solution boride ceramic does not contain metal, so that a large amount of metal cannot permeate into the cubic boron nitride layer under high-temperature and high-pressure conditions, meanwhile, a chemical reaction can occur at an interface of a mixed initial material of a titanium-tungsten boride ceramic substrate and the cubic boron nitride layer under the high-temperature and high-pressure conditions to form chemical bond combination, and the composite sheet has the characteristics of good thermal stability, difficulty in layering, good crack resistance, good collapse resistance and the like.

Description

technical field [0001] The invention relates to the technical field of preparation of a polycrystalline cubic boron nitride composite sheet for cutting tools, in particular to a polycrystalline cubic boron nitride composite sheet and a preparation method thereof. Background technique [0002] The thermal stability of cubic boron nitride is better than that of artificial diamond, and it can still maintain high enough mechanical properties and hardness at high temperatures, and has good red hardness; cubic boron nitride has a stable structure, high oxidation resistance, and chemical stability Well, compared with diamond, it is especially good that cubic boron nitride does not chemically react with iron group elements at temperatures as high as 1100~1300 °C, so cubic boron nitride is especially suitable for processing ferrous metal materials. Polycrystalline cubic boron nitride is made of cubic boron nitride single crystal, which can be sintered at ultra-high pressure and high ...

AI Technical Summary

Problems solved by technology

However, the main problems of using the alloy matrix still exist, such as: 1) the metal of the alloy layer will infiltrate into the CBN layer in a large amount, thereby reducing the thermal stability of the composite sheet; 2) the interface bonding force is still combined with the metal infiltration layer, and the delamination rate is high; 3) The difference in thermal expansion coefficient between the substrate and the CBN layer is large, and the crack resistance and collapse resistance of the product are poor; 4) The heat resistance of the alloy matrix polycrystalline cubic boron nitride composite sheet is poor, and the vacuum welding temperature in the later stage of tool production is limited.

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