Oxidation behavior of thermal barrier coatings obtained by detonation spraying

Thermal barrier coatings (TBCs) have been successfully obtained by detonation spraying, through optimizing the spray parameters (especially the ratio of C2H2 to O2). The oxidation behaviors of detonation sprayed TBCs at 1000 and 1100 °C were studied. The results indicated that the detonation sprayed TBCs were uniform and dense, with a few microcracks in the ceramic coats and a rough surface of bond coats. At the high temperature, the dense detonation sprayed ceramic coats with low porosity could obviously decrease the diffusive channels for oxygen and reduce the oxygen pressure (Po2) at the ceramic/bond coat interface. Under the lower oxygen pressure at the interface, it was advantageous to the formation of a continuous protective Al2O3 layer and the growth of a thermally grown oxide layer (TGO) obeyed the fourth power law.