低压等离子喷涂NiCoCrAlYTa涂层的氧化动力学

Oxidation kinetics of NiCoCrAlYTa coating by low pressure plasma spraying

采用低压等离子喷涂技术在镍基单晶高温合金上制备NiCoCrAlYTa涂层,研究涂层在900、1000和1100℃下恒温氧化200h的氧化动力学规律。通过表面XRD和SEM分析,初步探讨了氧化动力学规律与氧化产物的关系。结果表明:900℃时NiCoCrAlYTa涂层的氧化曲线符合对数规律,氧化产物主要为θ-Al2O3相;1000℃时NiCoCrAlYTa涂层的氧化曲线符合抛物线规律,氧化产物主要是θ-Al2O3和α-Al2O3相的混合物;1100℃时NiCoCrAlYTa涂层的氧化符合立方规律,氧化产物主要是α-Al2O3相。根据实验结果经计算得到NiCoCrAlYTa涂层氧化过程中θ-Al2O3的形成激活能为151.78kJ/mol,α-Al2O3的形成激活能为270.25kJ/mol。

The NiCoCrAlYTa coating was prepared on Ni-based single crystal super-alloys by low pressure plasma spraying （LPPS）. Oxidation kinetics of the coating oxidated for 200 h at three different temperatures was investigated. The results show that the oxidation behaviour of NiCoCrAlYTa coating conforms to different dynamical rules including the logarithmic equation, the parabola equation and the cubical equation at 900, 1 000 and 1 100℃, respectively. During the process of oxidation, θ-Al2O3 forms at 900 ℃. Both θ-Al2O3 and α-Al2O3 forms at 1 000 ℃, and α-Al2O3 forms at 1 100℃. The activation energies of θ-Al2O3 and α-Al2O3 are 151.78 and 270.25 k J/mol, respectively.