PREPARATION METHOD OF NICKEL-DIAMOND COMPOSITE POWDER BY HYDROGEN REDUCTION PROCESS

摘要

PURPOSE: A hydrogen reduction process for establishing technology for preparing nickel-diamond composite powder having a required composition within a relatively short reaction time as a single process is provided. CONSTITUTION: In a method for preparing composite powder in which nickel is coated on the surface of artificial diamond particles, the preparation method of nickel-diamond composite powder by hydrogen reduction process comprises a pretreatment step of sensitization treatment of the surface of artificial diamond particles used as a core using SnCl2 and activation treatment of the artificial diamond particles using PdCl2; a step of adding the pretreated diamond to an autoclave having high temperature and pressure into which nickel sulfate coating solution is charged, sealing the pretreated diamond in the autoclave, and heating the pretreated diamond to a reaction temperature of 150 to 180 deg.C as stirring the pretreated diamond, wherein the nickel sulfate coating solution is prepared by mixing and dissolving 115 to 165 g of NiSO46H2O, 150 g of (NH4)2SO4 and 72 to 102 cc of NH4OH for 1000 mL of coating solution; and a reduction step of starting hydrogen reduction by charging hydrogen gas of 20 to 30 atmospheric pressures into the autoclave if it reaches the reaction temperature, and reacting the reactants to a speed of 600 to 800 rpm for 15 to 30 min by a time point when pressure of hydrogen is not changed so that nickel is coated on the surface of diamond particle.