Commercial thermal barrier coatings with a double-layer bond coat on turbine vanes and the process repeatability

An investigation was conducted to develop a commercial thermal barrier coating (TBC) system with a double-layer bond coat on Ni-base superalloy turbine vanes. Surface morphology and cross-section microstructure of the developed coatings were studied by using Optical Microscope and Scanning Electron Microscope (SEM). Experimental and production results showed that a TBC system with good adherence and a repeatable process to apply the coatings were obtained. Furthermore, the repeatability of the vapor phase coating process, high velocity oxy-fuel (HVOF), and air plasma spray (APS) process were discussed. Finally, the advantage and the future possible improvement of the investigated TBC system were also proposed.