An ignition plug, and an insulating material using the same

文件类型：PDF文档
文件大小：759K
PROBLEM TO BE SOLVED : To provide an insulating material having excellent voltage endurance characteristics and an ignition plug using the same.SOLUTION : The insulating material comprises an alumina-based sintered body 1 having an alumina crystal as a main phase and having an amorphous grain boundary phase 12 at grain boundaries of crystal grains 11 constituting the alumina crystal. In the alumina-based sintered body 1, the grain boundary phase 12 contains an oxide of a rare earth element and/or an oxide of a group 4 element of the periodic table as a specific component in a glass component in which CaO and/or MgO is added to SiO. In the cross section of the alumina-based sintered body 1, the crystal grains 11 of the alumina crystal have an average crystal grain size of ≤2 μm and the grain boundary phase 12 has average peripheral circularity of 0.4-0.6. The ignition plug uses the insulating material comprising the alumina-based sintered body 1 as an insulator.