a Study of Oxidation Kinetics of NiCoCrAlYTa Coating on Ni-Based Single Crystal Super-Alloy

Abstract: The NiCoCrAlYTa coating  was prepared on Ni-base single crystal super-alloys by low pressure plasma spraying(LPPS). Oxidation kinetics and oxidation mechanisms of coating at 900�C�A1000�C�A1100�C were studied. The oxide scale and surface morphology of NiCoCrAlYTa coating were investigated by means of  XRD and SEM.The result shows that there are different oxidation dynamical regulars at the above three different temperature. The oxidation kinetics of NiCoCrAlYTa coating follows cubical equations at 1100�C, parabola equations at 1000�C,and logarithmic equations at 900�C. θ�|Al₂O₃ and a-Al₂O₃ as protective oxide scale were formed on the surface of the NiCoCrAlYTa coatings after 200 hours oxidation at three different temperature. According to the experimental results,θ�|Al₂O₃ oxide scale activation energy is 151.78kJ/mol and a-Al₂O₃ oxide scale activation energy is 270.25kJ/mol