Preparation method of cubic boron nitride and diamond polycrystal with nanometer structure

Abstract

The invention relates to a preparation method of a cubic boron nitride and diamond polycrystal with a nanometer structure. The preparation method comprises the steps: with hexagonal boron nitride and diamond mixed powder or cubic boron nitride and diamond mixed powder as the raw material, purifying for removing impurities in the raw material, then, assembling a sintering unit without adding any binder, and directly sintering at high temperature and superhigh pressure to prepare the cubic boron nitride and diamond polycrystal with the nanometer structure, wherein diamond accounts for 10-90% of the mass percentage of the raw material. The cubic boron nitride and diamond polycrystal with the nanometer structure is uniform in phase distribution, cubic boron nitride crystal grains have nanometer sizes, and diamond crystal grains are uniformly distributed in the nano cubic boron nitride crystal grains, thus a nanometer cubic boron nitride and diamond interface which is compact in combination and high in strength is formed at a large area. Therefore, the hardness of the high-performance cubic boron nitride and diamond polycrystal with the nanometer structure is equal to that of a diamond monocrystal, and the thermal stability, hardness and wear resistance of the high-performance cubic boron nitride and diamond polycrystal with the nanometer structure are also remarkably higher than those of a diamond polycrystal containing a metal binder.

Description

[0001] The invention relates to a method of preparing high-performance nanostructured cubic boron nitride-diamond polycrystalline superstructure by using hexagonal boron nitride and diamond mixed powder or cubic boron nitride and diamond mixed powder as raw materials, through purification treatment, under high temperature and ultra-high pressure conditions. The method for hard materials belongs to the field of inorganic non-metallic materials. technical background [0002] Diamond and cubic boron nitride are the two most widely used superhard materials in industry. Diamond is the hardest substance known in nature. It has extremely high wear resistance, compressive strength, and heat dissipation rate. Diamond single crystals are expensive and have dissociation surfaces. Polycrystalline diamond materials with higher cost performance are used in many industries. instead of diamond single crystals. Polycrystalline diamond is widely used in the cutting processing of non-ferrous me...

AI Technical Summary

Problems solved by technology

However, due to the large particle size of the traditional artificial cubic boron nitride-diamond polycrystalline material, it is difficult to achieve the flatness and sharpness of the cutting edge for ultra-fine cutting tools

In addition, most of the traditional artificial cubic boron nitride-diamond polycrystalline materials contain binders, such as: Co, Ni, etc., which seriously affect the hardness, wear resistance and thermal stability of cubic boron nitride-diamond polycrystalline materials.

[0004] Use hexagonal boron nitride and diamond mixed powder or cubic boron nitride and diamond mixed powder as raw materials to prepare high-performance nanostructured cubic boron nitride-diamond polycrystal under high temperature and ultra-high pressure.

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