Using a DOE Approach to Optimize a LVPS Bond Coat and APS Top Coat for TBC Systems

Abstract

Acquisition of a new LVPS and APS coating system at Delta Air Lines necessitated optimization of the coating parameters on both systems; especially for application of bond coat (LVPS) and top coat (APS) for a TBC coating system. To expedite the coating optimization; it was determined that a design of experiments (DOE) approach would best enable the establishment of the operating window for the two systems. Samples prepared were primarily evaluated for their performance while exposed to a cyclic oxidation cycle. Samples were also evaluated for the microstructure and composition using energy dispersive spectroscopy (EDS) analysis. Samples from the ceramic coating DOE were also evaluated for their erosion characteristics. Results indicate a low correlation between the individual bond coat parameters evaluated to the furnace cycle life. However; the top coat spray parameters were found to have a greater correlation to furnace cycle life and erosion performance.