CORROSION-RESISTANT SILICON NITRIDE CERAMIC

PROBLEM TO BE SOLVED: To provide corrosion resistant silicon nitride ceramic which prevents a coating layer mounted on a substrate from exfoliating even under an environment in which a heat cycle occurs like with a thermal engine. SOLUTION: The corrosion resistant silicon nitride ceramic is constituted by laminating an adhesion acceleration layer 3, a stress relaxation layer 4 and a crack progression prevention layer 5 in this order a ceramic substrate 2 composed of a silicon nitride as a principal component, and laminating a surface corrosion resistance layer 6 composed of zirconium oxide stabilized by a periodic table group 3a element thereon, wherein the coefficient of thermal expansion α0of the ceramic substrate 2, the coefficient of thermal expansion α1of the adhesion acceleration layer 3, the coefficient of thermal expansion α2of the stress relaxation layer 4, the coefficient of thermal expansion α3of the crack progression prevention layer 5, and the coefficient of thermal expansion α4of the surface corrosion resistance layer 6 satisfy relational expressions (I) to (III). COPYRIGHT: (C)2006,JPO&NCIPI