CERAMIC HEATER AND GLOW PLUG

PROBLEM TO BE SOLVED: To achieve both of the enhancement in oxidation resistance of a base included in a ceramic heater, and the increase in sinterability.SOLUTION: A ceramic heater comprises: a base including silicon nitride as a primary component and additionally, a rare earth element, and provided to extend in an axial direction; and a conductive part including two extending parts buried in the base and extending along the axial direction in parallel with each other and a joint portion. In a section orthogonal to the axial direction, where the two extending parts appear, the content of the rare earth element in the base in a center portion of the ceramic heater is higher than that in the base in a surface layer portion; the content of the rare earth element in the base of the center portion is 0.6-2.0 atm%.SELECTED DRAWING: Figure 3 【課題】セラミックヒータに含まれる基体の耐酸化性の向上と焼結性の向上とを両立させる。【解決手段】窒化珪素を主成分として希土類元素をさらに含有し軸線方向に延設された基体と、基体の内部に埋設され互いに軸線方向に沿って延設された２つの延設部及び連結部を含む導電部と、を備えるセラミックヒータは、軸線方向と直交し２つの延設部が現われる断面においてセラミックヒータの中心部の基体における希土類元素の含有率は、表層部の基体における含有率に比べて高く、中心部の基体における希土類元素の含有率は、０．６ａｔｍ％以上２．０ａｔｍ％以下である。【選択図】図３