Nanometer niobium carbide/carbon nanotube reinforced diamond composite and a preparation method thereof

A method for preparing a nanometer niobium carbide/carbon nanotube reinforced diamond composite, comprising the following step:

• (1) preparing nanometer niobium carbide/carbon nanotube composite powders;
• by,
• weighing nanometer niobium carbide and carbon nanotube at a mass ratio of (5˜10):1, which are added into distilled water respectively and ultrasonic dispersed for 0.5 h˜1 h, giving an aqueous dispersion of nanometer niobium carbide and an aqueous dispersion of carbon nanotube;
• thereafter, magnetically stirring the aqueous dispersion of nanometer niobium carbide and slowly adding the aqueous dispersion of carbon nanotube dropwise, and drying in vacuum after 30 min to obtain the composite powders, adding the composite powders into a hard alloy ball-milling tank, into which are additionally added hard alloy grinding balls, wherein the ratio of grinding balls to materials is 40:1, the ball-milling rate is 400 r/min, the time for ball-milling is 3 h˜6 h, and dried in vacuum to obtain nanometer niobium carbide/carbon nanotube composite powders;
• (2) preparing of nanometer niobium carbide/carbon nanotube/matrix composite powders;
• by,
• weighing the nanometer niobium carbide/carbon nanotube composite powders obtained in step (1) and the matrix powders at weight percentages of nanometer niobium carbide/carbon nanotube composite powders of 0.5 wt %˜3 wt % and matrix powders of 97 wt %˜99.5 wt %, on which is then conducted the planetary ball milling, wherein the ratio of grinding balls to materials is 6:1, the ball-milling rate is 320 r/min, the time for ball-milling is 3 h˜6 h, and dried in vacuum to obtain nanometer niobium carbide/carbon nanotube/matrix composite powders;
• (3) weighing the nanometer niobium carbide/carbon nanotube/matrix composite powders obtained in step (2) and diamond grains at volume percentages of nanometer niobium carbide/carbon nanotube/matrix composite powders of 70 vol %˜80 vol % and diamond grains of 20 vol %˜30 vol %, and then placed into a three-dimensional mixing machine to mix for 1 h˜3 h, giving mixed powders;
• (4) charging into graphite moulds the mixed powders obtained in step (3), and sintering in a hot pressing sintering furnace, giving nanometer niobium carbide/carbon nanotube reinforced diamond composites.