Heater-equipped spark plug.

摘要

A recess (11) is formed in an insulator nose (10). Arranged within the recess (11) is a heater (13) formed, for example, by baking a metal paste of powder of a metal such as Pt or W, alumina powder and an acrylic or cellulose-base binder. The heater (13) is covered and held in place by a high softening-point glass layer (15) with an alumina layer (14) interposed therebetween. Preferably, the alumina layer (14) on the heater (13) can have a thickness in a range of 20-200 mu m whereas the thickness of the high softening-point glass layer (15) can range from 30 mu m to 500 mu m.