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 co ating material. For evaluation of peeling property of plasma sprayed c oating, it is demanded that thermal properties of plasma sprayed coati ng are estimated in detail. In this study, the results of comparison o f thermal properties between bulk material and plasma sprayed material are investigated to design the ceramic coating quantitatively. Therma l conductivity of plasma sprayed MgO . Al2O3 is decreased by approxima tely 50% to that of sintered MgO . Al2O3. Thermal conductivity of plas ma sprayed 410SS agreed well with the calculation results of relation between porosity and thermal conductivity of iron sintered material. T hermal expansions of atmospheric plasma sprayed MgO . Al2O3 and bulk 4 10SS, respectively. Therefore, as to material design on ceramic coatin g, it was made clear that thermal conductivity is more important than thermal expansion. (C) 1998 Elsevier Science S.A. All rights reserved.