Abstract
Metal-ceramic coatings have been widely used for industrial applications, mainly in the thermal barrier coating technology (TBC). Plasma spraying is the common manufacturing process of TBC's. Conventional thermal barrier coatings consist of a metallic bond coat layer and an insulating ceramic overlay. Graded coatings or functionally gradient coatings have also been applied in order to solve the problems associated with the early spallation of plasma-sprayed conventional TBCs. Temperatures and gradients during plasma spraying have and important influence on the coating quality, specially the temperature of the particles just hitting the substrate surface. When applying so distinct materials like metals and ceramics this fact has an increased importance. In this work metal-ceramic coatings have been applied on metallic substrates. The interfacial temperature measurements were performed by optical pyrometry. The substrate temperature was measured by thermocouples. The adhesion of the coatings was determined by standard ASTM tests and correlated with the measured temperatures. In a general way, results show that the coatings with lower adhesion values were that with lower interfacial measured temperatures.
