摘要 |
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 expansionα<SB>0</SB>of the ceramic substrate 2, the coefficient of thermal expansionα<SB>1</SB>of the adhesion acceleration layer 3, the coefficient of thermal expansionα<SB>2</SB>of the stress relaxation layer 4, the coefficient of thermal expansionα<SB>3</SB>of the crack progression prevention layer 5, and the coefficient of thermal expansionα<SB>4</SB>of the surface corrosion resistance layer 6 satisfy relational expressions (I) to (III). COPYRIGHT: (C)2006,JPO&NCIPI
|