ZIRCONIUM DIBORIDE SINTERING MATERIAL EXCELLENT IN CORROSION RESISTANCE AND THERMAL SHOCK RESISTANCE

摘要

PURPOSE: A zirconium diboride(ZrB2) sintering material containing mesophase pitch and C-based powder is provided, which has high corrosion resistance and high thermal shock resistance to molten metals for thermocouple protectors, rollers, and nozzles. CONSTITUTION: The ZrB2 sintering material comprise 65-93wt.% of ZrB2 powder(5-10micrometer) with a high purity more than 95%, 5-20wt.% of C-based powder( = 30micrometer) such as cokes and/or graphite powder and 2-15wt.% of mesophase pitch( = 40micrometer), where the C-based powder contains more than 99% of C and less 1% of volatile powder and ash, and the pitch with a softening point higher than 280deg.C gives a carbonization yield(at 1000deg.C) more than 70wt.%.