| 摘要 |
PURPOSE:To improve calcinability and readily enable obtaining of a high-density calcined compact having a high strength at high temperatures, etc., by providing a coating layer composed of one of metal carbide, nitride and boride formed by dipping on the surface of hardly calcinable powder. CONSTITUTION:Hardly calcinable powder, e.g. diamond, boron nitride, silicon carbide, zirconium boride or boron carbide, is dipped in a molten salt bath prepared by blending a molten halide containing at least a fluoride with the objective coating metal component, preferably a bath composed of an alkali metal chloride-alkaline earth metal chloride-alkaline earth metal fluoride to initiate disproportionation reaction on the surface of the hardly calcinable powder and form a nearly amorphous coating layer of the metal carbide, nitride, boride, etc., rich in activity. The resultant coated powder is then calcined by a dynamic or static ultrahigh pressure method to afford a calcined compact, which is subsequently bound with a binder to provide abrasive grains, grindstones, etc. |
