Improvement of oxidation resistance of γ-TiAl At 800 and 900 °C in air by TiAl2 coatings
Improvement of oxidation resistance of γ-TiAl At 800 and 900 °C in air by TiAl2 coatings
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DOI：
10.1016/j.msea.2005.01.027
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发表时间：
2005-04
期刊：
影响因子：
6.4
通讯作者：
Zhenyu Liu;Guo-dong Wang
中科院分区：
文献类型：
--
作者：
Zhenyu Liu;Guo-dong Wang
本文采用近场磁控溅射沉积（CFMSD）技术，在γ-TiAl衬底上制备了厚度约为20μm的γ-TiAl和tial2涂层。镀层质量良好，在沉积tial2镀层的横截面上未发现微裂纹。在800°C和900°C的空气中进行氧化暴露试验，以评估涂层和铸造γ-TiAl的抗氧化性。γ-涂层与铸态TiAl具有相似的氧化性能。随着Al2O3+ tio2混合物的形成，两者的氧化物损失都很大，没有发现富Al2O3层。而在800℃和900℃时，tial2涂层上仅形成θ-相结构的外部al2o3层，θ- al2o3鳞片具有较好的保护能力，质量增益低，鳞片粘附性好。氧化暴露后，tial2涂层几乎不存在微裂纹，并且在tial2涂层与γ-基体之间存在一个约5μm的互扩散区，这可能是涂层与基体之间的冶金结合。
In the present work, γ-TiAl and TiAl2coatings with the thickness of about 20μm were made on γ-TiAl substrates by using a close-field magnetron sputter deposition (CFMSD) technique. The coatings showed good quality with no micro-cracks being observed in the as-deposited TiAl2coating cross-sections. Oxidation exposure tests at 800 and 900°C in air were carried out to assess the oxidation resistance of the coatings and the cast γ-TiAl. The γ-coating and cast TiAl showed similar oxidation performance. Both of them had suffered great oxide losses with the formation of Al2O3+TiO2mixtures and no Al2O3-rich layer was found in either case. By contrast, only external Al2O3layers with a θ-phase structure was formed on the TiAl2coatings at 800 and 900°C, and the θ-Al2O3scales showed high protective ability with low mass-gains and good scale adherence. After the oxidation exposures, the TiAl2coating remained to be almost free of micro-clacks, and an inter-diffusion region of about 5μm was observed between the TiAl2coating and the γ-substrate, which could act as a metallurgical bonding between the coating and substrate.