INSULATOR FOR SPARK PLUG AND SPARK PLUG

文件类型：PDF文档
文件大小：1092K
An insulator for spark plug with a main constituent of alumina and containing silicon includes a grain boundary phase positioned between alumina particles. The grain boundary phase contains : a group 2A element; a rare earth element; and at least one kind of zirconium, titanium, chrome, niobium, manganese, and iron (a first element). Assuming that a total amount of the rare earth element is X (mass %), a total amount of the group 2A element is Y (mass %), and a total amount of the first element is Z (mass %), the following are met : [in-line-formulae]0.40≦Y/X≦2.00[/in-line-formulae] [in-line-formulae]0.10≦Z/X≦0.40.[/in-line-formulae]