| 摘要 |
PURPOSE:To produce a high-density sintered boron nitride at low cost, by blending boron nitride powder of hexagonal system with specific amounts of an alkaline earth metallic compound and boron carbide, molding and burning in a nitrogen atmosphere. CONSTITUTION:Boron nitride powder of hexagonal system ground pulverized into >=about 5m<2>/g BET specific surface area is blended with 0.1-20wt.% alkaline earth metallic compound (calcium carbonate) and 0.1-20wt.% boron carbide (<=50mu particle size) and granulated. Then the granules are molded into a given shape, heated in nitrogen or in a nonoxidizing atmosphere containing nitrogen at a rate of heating of about 20-100 deg.C/min to about 1,600-1,800 deg.C, burnt for about 2-10hr and boron carbide is reacted with nitrogen to give boron nitride. Consequently, high-quality sintered boron nitride of hexagonal system is obtained. |
