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采用溶胶-凝胶法在γ-TiAl合金表面制备了Al2O3涂层,通过等温氧化实验研究了合金基材和涂层试样高温氧化的动力学特性,推导了动力学方程的算法,并估算了氧化膜与基材间的热应力。结果表明:空白试样高温氧化前期的动力学呈立方规律,但随后转化为直线规律;涂层试样高温氧化的动力学则由直线规律转化为抛物线规律。此外,Al2O3涂层试样的氧化速率常数比空白对照样降低近90%;Al2O3涂层通过降低氧化膜与基材间的热应力,提高了合金的抗循环氧化性能。
The Al2O3 coating was prepared on the surface of γ-TiAl alloy by sol-gel method. The kinetics of high temperature oxidation of alloy substrate and coating was studied by isothermal oxidation experiment. The kinetic equation was deduced Thermal stress between the oxide film and the substrate. The results show that the kinetics of blank sample at high temperature is cubical, but then changes to linear rule. The kinetics of oxidation at high temperature is transformed from straight line to parabolic law. In addition, the oxidation rate constant of Al 2 O 3 coating decreased nearly 90% compared with that of blank control. Al 2 O 3 coating improved the cyclic oxidation resistance of the alloy by reducing the thermal stress between the oxide film and the substrate.