ON THE EXPERIMENTAL CORRELATION BETWEEN THE PROPERTIES OF YTTRIA PARTIALLY STABILISED ZIRCONIA COATINGS AND THE PROCESS CHARACTERISTICS

摘要

Plasma spray deposited Ytrria Partially Stabilised Zirconia (or YPSZ) is used in several industrial sectors for various purposes, typically as a thermal barrier coating (TBC) for gas turbine blades and vanes in the aerospace and stationary power generation. In this application, the TBC barrier is normally applied on a bond coat substrate of MCrAlY. Several parameters are important in determining the final properties of a TBC system: among these, not only the spraying conditions, but also the composition of the powder and the heat treatment performed after deposition. This paper reports the results of a study aimed at determining the relation between the process characteristic (plasma spray process conditions and heat treatment) and the coating properties. The coatings obtained after parameters optimisation have been completely characterized and the most interesting set of parameters has been used to produce samples that have been submitted to heat treatment in air, vacuum and a combination of both. The crystal lattice structure has been investigated in order to verify the modification of the structure of powder and coatings as sprayed and heat treated.