Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

For diamond/metal composites it is better to use diamond particles coated with metal carbide because of improved wettability between the diamond particles and the matrix. In this study, the coating of diamond particles with a chromium carbide layer is investigated. On heating diamond and chromium powders at 800~900 °C in molten salts of LiCl, KCl, CaCl₂, the diamond particles are coated with Cr₇C₃. The surfaces of the diamond powders are analyzed using X-ray diffraction and scanning electron microscopy. The average thickness of the Cr₇C₃ coating layers is calculated from the result of the particle size analysis. By using the molten salt method, the Cr₇C₃ coating layer is uniformly formed on the diamond particles at a relatively low temperature at which the graphitization of the diamond particles is avoided. Treatment temperatures are lower than those in the previously proposed methods. The coated layer is thickened with an increase in heating temperature up to 900 oC. The coating reaction of the diamond particles with chromium carbide is much more rapid in LiCl-KCl-CaCl₂ molten salts than with the molten salts of KCl-CaCl₂.