PRODUCTION OF LOW THERMAL EXPANSION CERAMIC COMPACT

摘要

PURPOSE:To reduce the burning shrinkage factor and thermal expansion coefficient and obtain a compact excellent in thermal shock resistance at a low water absorptivity by adding a forming assistant to a main raw material composed of low expansion glass powder and a low expansion ceramic aggregate and burning the resultant compact at a prescribed temperature. CONSTITUTION:A forming assistant (e.g. methyl cellulose or micro-silica) is added to 20-70wt.% low expansion glass powder and 30-80wt.% low expansion ceramic aggregate as a main raw material and the resultant mixture is then press formed. The glass powder contains sodium oxide and has -7 to 7X10<-6>/ deg.C thermal expansion coefficient. The ceramic aggregate has a higher softening temperature than that of the glass powder and -7 to 7X10<-6>/ deg.C thermal expansion coefficient and is composed of an Li2O-Al2O3-SiO2 system. The resultant compact is subsequently burned at 700-1000 deg.C temperature to afford the objective low expansion ceramic compact.