High-quality polycrystalline diamond compact and preparation method thereof

Abstract

The invention relates to the technical field of super-hard composite materials, particularly to a high-quality polycrystalline diamond compact and a preparation method thereof. According to the invention, the high-quality polycrystalline diamond compact is manufactured by using double-beam 3D printing equipment which performs processing with high-power continuous beams and ultra-fast pulsed laserbeams alternately; and gradual transition layers are formed among layers, so bonding between a matrix and diamond and between the diamond and nickel is firm, and an interlayer interface is free of sudden changes in thermal and mechanical quantities. The polycrystalline diamond compact of the invention comprises, arranged from bottom to top, the matrix, a matrix-diamond gradual transition layer, adiamond layer, a diamond-nickel gradual transition layer, a nickel layer and a cobalt-free binder. The diamond-nickel gradual transition layer improves the heat dissipation performance of the polycrystalline diamond compact, prevents thermal stress corrosion from generating cracks on the surface of the diamond layer, and greatly improves the thermal stability of the polycrystalline diamond compact. Double-beam 3D printing technology used in the invention makes D-D bonding firm and ultra-high hardness to be obtained, so the polycrystalline diamond compact has high heat resistance, wear resistance and impact toughness, and thus has prolonged service life.

Description

technical field [0001] The invention relates to the technical field of superhard composite materials, in particular to a high-quality diamond composite sheet and a preparation method thereof. Background technique [0002] At present, metal cobalt (Co) is used as a binder in the manufacture of diamond compacts in the world. The thermal expansion coefficient of Co is larger than that of diamond particles. At 700-760°C, the expansion of Co will make the diamond particles The bonding between the diamonds is separated, which seriously reduces the wear resistance of diamonds. Therefore, acid corrosion is usually used to precipitate Co from the diamond particles, and the corrosion depth can reach about 0.1-0.5mm. This method of removing Co, to a certain extent The wear resistance of diamond can be restored, but it will make the diamond layer more porous, thereby reducing the mechanical structure strength of the diamond composite sheet, so a diamond ring must be added to the diamond...

AI Technical Summary

Problems solved by technology

[0002] At present, metal cobalt (Co) is used as a binder in the manufacture of diamond compacts in the world. The thermal expansion coefficient of Co is larger than that of diamond particles. At 700-760°C, the expansion of Co will make the diamond particles The bonding between the diamonds is separated, which seriously reduces the wear resistance of diamonds. Therefore, acid corrosion is usually used to precipitate Co from the diamond particles, and the corrosion depth can reach about 0.1-0.5mm. This method of removing Co, to a certain extent It can restore the wear resistance of diamond, but it will make the diamond layer more porous, thereby reducing the mechanical structure strength of the diamond composite sheet, so it is necessary to add a diamond ring to the diamond outer ring to increase its strength

In short, the current preparation method of adding Co binder phase to diamond compacts limits the high wear resistance, high impact toughness and durability of diamond compacts.

[0003] In the prior art, there are also methods of using 3D printing technology to manufacture diamond composite sheets, but no matter whether the material is made into powder, powder feeding or wire feeding, a high-power continuous laser (or electron beam) is used, which can make the material Rapid melting and solidification make the crystal grains small, uniform in composition, and dense in structure. The comprehensive mechanical properties of 3D printed products are excellent. At the same time, the material utilization rate is high and the manufacturing is fast. However, this high-power continuous laser belongs to thermal processing. When the material is melted and solidified by point-by-point, line-by-line, and layer-by-layer printing, due to the thermal stress generated by the thermal effect of heat conduction, defects will inevitably occur on the boundaries and interfaces between printed points, lines, and layers, and even cause Partial cracking, which is a common shortcoming in 3D printing metal products at present, so the diamond composite sheet made by 3D printing method in the prior art cannot be used under high temperature and high pressure

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