Material design of ceramic coating by plasma spray method

In the ceramic coating on substrate, cracking and peeling occur due to the difference of thermal expansion between substrate material and coating material. For evaluation of peeling property of plasma sprayed coating, it is demanded that thermal properties of plasma sprayed coating are estimated in detail. In this study, the results of comparison of thermal properties between bulk material and plasma sprayed material are investigated to design the ceramic coating quantitatively. Thermal conductivity of plasma sprayed MgO·Al2O3 is decreased by approximately 50% to that of sintered MgO·Al2O3. Thermal conductivity of plasma sprayed 410SS agreed well with the calculation results of relation between porosity and thermal conductivity of iron sintered material. Thermal expansions of atmospheric plasma sprayed MgO·Al2O3 and bulk 410SS, respectively. Therefore, as to material design on ceramic coating, it was made clear that thermal conductivity is more important than thermal expansion.