CERAMIC HEATER AND GLOW PLUG

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PROBLEM TO BE SOLVED : To provide a ceramic heater that can prevent corrosion by calcium component, while preventing defects such as a crack or the like resulting from thermal stress. SOLUTION : A glow plug comprises a main clasp 2, a ceramic heater 4 and the like. The ceramic heater 4 has a base substrate 21 having a round-bar shape and extending in the direction of an axis in which a heating element 22 elongated in a horseshoe shape is held buried. The heating element 22 has at least one of silicide, nitride and carbide of molybdenum, and silicide, nitride and carbide of tungsten as a principal component. The base substrate 21 comprises silicon nitride as a principal component, rare earth component in an amount of 4 to 25% by mass, calculated as an oxide equivalent, chromium component in an amount of 1 to 8% by mass, calculated as a chromium silicide equivalent and aluminum component in an amount of 0.02 to 1.0% by mass, calculated as a nitride aluminum equivalent. The aluminum component suppresses erosion of the base substrate due to calcium component or the like included in engine oil. COPYRIGHT : (C)2008, JPO&INPIT