| abstract |
PURPOSE:To obtain finely powdered silicon carbide with less unevenness by treating carbonaceous powder or a carbon precursor with a (modified) silicic acid soln. and heating the resulting mixture in a nonoxidizing atmosphere. CONSTITUTION:Carbonaceous powder such as carbon black powder or a carbon precursor such as starch, sucrose, PVA, PVC or other org. substance convertible into carbonaceous residue at 200-1,500 deg.C in a nonoxidizing atmosphere is treated with a silicic acid soln. or sol obtd. by hydrolyzing a hydrolyzable silicon compound or a modified silicic acid soln. or sol contg. dissolved ammonium ions, org. amine or the like. The resulting mixture is heated at 1,350-1,850 deg.C in a nonoxidizing atmosphere of N2, CO, Ar or the like to manufacture silicon carbide. In a conventional method, silica powder and carbon powder as starting material are mixed in a solid phase, so as ununiform crystal phase or other defect is caused sometimes owing to ununiform mixing. This method is a liq. phase mixing method, so very uniform mixing is attained, and finely powdered silicon carbide with less unevenness in grain size is obtd. |