| abstract |
An object of the present invention is to provide a corrosion-resistant silicon nitride ceramic that can prevent a coating layer provided on a substrate from peeling even under an environment where a heat cycle occurs such as a heat engine. An adhesion promoting layer, a stress relaxation layer, and a crack propagation preventing layer are laminated in this order on a ceramic substrate mainly composed of silicon nitride, and stabilized by a group 3a element in the periodic table. laminated surface corrosion-resistant layer 6 composed mainly of zirconium oxide is, the thermal expansion coefficient alpha 0 of the ceramic substrate 2, the thermal expansion coefficient alpha 1 of the adhesion promoting layer 3, the thermal expansion coefficient alpha 2 of the stress relaxing layer 4, cracking thermal expansion coefficient alpha 3 and the thermal expansion coefficient alpha 4 of the surface corrosion-resistant layer 6 of the extension preventing layer 5 is a corrosion-resistant silicon nitride ceramic that satisfies the following relational formula (I) ~ (III). [Expression 10] [Selection] Figure 1 |