| 摘要 |
PURPOSE:To improve strength, heat resistance and heat insulating property by specifying the particle diameter and BET specific surface area of a calcined powder before molding and calcining. CONSTITUTION:Oxides of bivalent metal elements (e.g. alkaline-earth metal elements having >=2.0m<2>/g BET specific surface area, ZrO2 and the like having >=10m<2>/g BET specific surface area, and P2O5 and the like having >=2.0m<2>/g are mixed with specified proportions. Especially, the bivalent metal elements include Ca as the essential component, which is combined with Sr or Ba to give 0.8-0.975 molar ratio of Ca/Ca+Ba+Sr. The mixture is calcined in an oxidative atmosphere at >=800 deg.C and pulverized to obtain a calcined powder having <=2mum average particle diameter and >=5m<2>/g BET specific surface area. This powder is molded and calcined in an oxidative atmosphere at >=1400 deg.C to obtain a phosphate sintered body essentially comprising a crystal phase expressed by MZr4P6-XO24-y (wherein M is a bivalent metal element and 0<x<1.0) and having <=5mum average particle diameter <=10 % porosity and <=3W/m K thermal conductivity. |
