对γ-TiAl合金的高温氧化防护
(1. 东北大学 材料与冶金学院，沈阳 110004；
2. 沈阳化工学院 应用化学学院，沈阳 110142)
摘 要: 以异丙醇铝(Al(OC3H7)3)为原料，采用溶胶−凝胶法在γ-TiAl基合金表面制备Al2O3涂层。以空白样品做对照，研究涂层的作用机制以及涂层对γ-TiAl基合金1 000 ℃高温氧化行为的影响。结果表明：采用浸涂工艺制备的涂层表面均匀、无裂纹，主要由γ- Al2O3相组成，厚度约为0.8 μm；等温氧化110 h后，空白试样和Al2O3涂层试样的氧化抛物线速率常数分别为4.85×10−12 和 3.31×10−13 g2/(cm4∙s)，涂层明显提高合金的抗氧化能力及抗循环氧化能力；空白样品上形成的氧化膜出现分层现象，而在涂层样品的Al2O3涂层中存在金红石型TiO2和α-Al2O3混合物。
关键字: Al2O3涂层；溶胶−凝胶法；γ-TiAl基合金；高温氧化
its oxidation protection for γ-TiAl based alloy at high temperature
（1. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China;
2. College of Applied Chemistry, Shenyang Institute of Chemical Technology, Shenyang 110142, China）
Abstract:With aluminum isopropoxide (Al(OC3H7)3) as precursor, an Al2O3 film was deposited on a γ-TiAl based alloy by sol-gel method. In comparison with the uncoated specimens, isothermal and cyclic oxidations at 1 000 ℃ were performed to test its effect on the oxidation behavior of the alloy. The possible mechanism of the thin film on the oxidation behavior of the alloy was discussed. The results show that the thin film synthesized using a dip-coating process is uniform and crack-free. The thin film mainly consists of γ-Al2O3 after heat treatment. The average thickness of the coating is about 0.8 μm. Oxidized for 110 h in air at 1 000 ℃, the average parabolic rate constants (kp) for the blank and coated specimens are 4.85×10−12 and 3.31×10−13 g2∙cm−4∙s−1. The Al2O3 film exhibits beneficial effects on the oxidation resistance of the alloy. The oxide scales formed on the uncoated specimens are delaminated. For the coated samples, beneath the Al2O3 film, a mixture layer of rutile TiO2 and α-Al2O3 exists.
Key words: Al2O3 coating; sol-gel method; γ-TiAl based alloy; high temperature oxidation
