Patent ID: 9362722
Filing Date: 2016-06-07
CPC Classification: B82Y,C04B,F02P,H01T

Claim Text:
1. A spark plug comprising: an insulator formed of an alumina-based sintered material, wherein the alumina-based sintered material contains an Al component, an Si component, a Group 2 element component, the Group included in the periodic table defined by Recommendations 1990, IUPAC, and a rare earth element component in such amounts that satisfy a condition (1): 0.25 ≦oxide-reduced amount (mass %) of the Si component ≦1.25, and a condition (2): 1.35 ≦[(oxide-reduced amount of the Si component)/((oxide-reduced amount of the Group 2 element component)/(oxide-reduced amount of the rare earth element component))]≦7.5, wherein the alumina-based sintered material includes alumina grains, and a glass phase including a crystal phase that satisfies a condition (