| 摘要 |
PROBLEM TO BE SOLVED: To increase the heat conductivity of an aluminous sintered compact based on alumina (Al2 O3 ) or an insulator for a spark plug while well maintaining various superior characteristics peculiar to it and to improve the heat radiating property. SOLUTION: The ratio (×100%) of the bulk density of aluminous ceramics to the density calculated from components constituting the ceramics is regulated to >=98% (relative density) and the alumina content of the ceramics is regulated to >=90%. The heat conductivity of the aluminous ceramics used, e.g. as an insulator for a spark plug is therefore increased without deteriorating various characteristics peculiar to it, the heat radiating property is surely improved and the preignition resistance can be improved. |
