對γ-TiAl合金的高溫氧化防護
(1. 東北大學(xué) 材料與冶金學(xué)院，沈陽 110004；
2. 沈陽化工學(xué)院 應(yīng)用化學(xué)學(xué)院，沈陽 110142)
摘 要: 以異丙醇鋁(Al(OC3H7)3)為原料，采用溶膠−凝膠法在γ-TiAl基合金表面制備Al2O3涂層。以空白樣品做對照，研究涂層的作用機制以及涂層對γ-TiAl基合金1 000 ℃高溫氧化行為的影響。結(jié)果表明：采用浸涂工藝制備的涂層表面均勻、無裂紋，主要由γ- Al2O3相組成，厚度約為0.8 μm；等溫氧化110 h后，空白試樣和Al2O3涂層試樣的氧化拋物線速率常數(shù)分別為4.85×10−12 和 3.31×10−13 g2/(cm4∙s)，涂層明顯提高合金的抗氧化能力及抗循環(huán)氧化能力；空白樣品上形成的氧化膜出現(xiàn)分層現(xiàn)象，而在涂層樣品的Al2O3涂層中存在金紅石型TiO2和α-Al2O3混合物。
關(guān)鍵字: Al2O3涂層；溶膠−凝膠法；γ-TiAl基合金；高溫氧化
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
