原料の選択が半炭化ケイ素さやの耐久性に及ぼす影響

Abstract

A heat-resistant semi silicon carbide sagger body could be produced by using black silicon carbide. Experiments were made to examine the effects of kinds of aggregate, combining clays and other additives on thermal shock resistance and oxidation of silicon carbide.The results obtained are as follows:(1) On thermal shock resistance, “Kibushi” clay of high plasticity both as an aggregate and as combining clay gives good effects. Burned “Kibushi” clay used as an aggregate gives better effects at S.K. 14 than S.K. 9, but fused “Kibushi” clay such as corhart is not effective as an aggregate.(2) Effects of other additives on oxidation of black silicon carbide by short-time heating are investigated through D.T.A., weight increase of black silicon carbide after burning and X-ray analysis. Copper carbonate and manganese fluoride increase the oxidation of silicon carbide, and borax which shows lower melting point prevents the oxidation. These results can be explained by the partial pressure of oxygen and their eutectic points with silica.(3) Borax as an additive gives better effects not only on the above physical properties but also on preventing the oxidation of silicon carbide.