Microstructures and properties of three kinds of thermal barrier coatings

Three kinks of thermal barrier coatings (TBC) were prepared with plasma spraying, and microstrutures and properties of the coatings were analyzed and compared. The results shows that the bonding strength of Al-1075 TBC is 24.66 MPa which is the highest strength and has great thermal shocking resistance. The bonding strength of KF-230 TBC is the lowest, 16.06 MPa. The bonding strength of LG-210 TBC is higher, but has the worst thermal shocking resistance. The analysis shows that the thermal grown oxide (TGO) plays an important role in failure of the TBCs. TGO is the origion of cracking, and is the passage of crack expansion. It is the weakest in the system. So restriction of TGO is a key method to increase the bonding strength and improve the thermal shocking resistance of the coating.