What is the purpose of gradient coating design?

       The so-called ladder coating refers to the intermediate transition layer sprayed between the metal substrate and the ceramic surface coating. Cracking or peeling of the ceramic coating often occurs at the interface between the ceramic coating and the metal substrate, or at the interface between the ceramic coating and the metal bonding substrate during spraying or working under high temperature cyclic conditions. This is due to the large difference in the expansion coefficient between the ceramic coating and the metal substrate, resulting in thermal expansion and shear stress. In order to reduce the thermal stress caused by uneven thermal expansion as much as possible and improve the thermal fatigue resistance, "gradient coating design" is usually used.