Effect of Surface Treatments on Lifetime and Failure Mechanism of Thermal Barrier Coatings

Abstract:

NiCrAlYSi bond coating has been deposited on DZ125 alloy substrates by arc ion plating. YSZ has been deposited on the bond coating by EB-PVD technology. The microstructure and interface morphology of the sandpapered (SS), polished (PS), vibratory polished (VS) and grit-blasted samples (GS) have been investigated and compared in detail. The results indicate that the bond coating surface has been polished and the roughness has been decreased due to the effect of surface treatments. Furthermore, effect of surface treatments on bond strength is studied which the bond strength has been increased by different surface treatments. The durability of these systems by different surface treatments has been measured and compared. Based on the electron microscopy observations, the failure mechanisms of thermal barrier coatings have been investigated by the various stages of cycle life.

Key words:TBC; EB-PVD; Surface Treatments; Interface Morphology; Failure Mechanism