TiAl合金表面SiO2防护涂层研究进展-中国材料进展

文章信息/Info

Author(s):: YAN Haojie; WU Liankui ; CAO Fahe; (School of Materials, Sun Yat-sen University, Shenzhen 518107, China)

Keywords:: TiAl alloy; silica coating; high temperature oxidation; surface modification; protective coating

摘要:: TiAl合金具有密度低、比强度高和高温抗蠕变性能好等优点，在航空航天及汽车工业等领域的高温结构部件中具有广阔的应用前景。然而，抗高温氧化性不足的问题限制了其应用。SiO2涂层结构致密，具有良好的化学稳定性和热稳定性，可有效改善TiAl合金的抗高温氧化性能，引起了研究人员的关注。然而，纯SiO2涂层存在结构单一、涂层与TiAl基体热膨胀系数差异较大、在长期高温环境服役时界面易失稳等问题。为此，TiAl合金表面SiO2复合涂层应运而生，主要包括在SiO2涂层和基体之间引入其他中间层形成多道防护层,以及将SiO2涂层作为中间层构筑复合涂层。简要介绍了TiAl合金的氧化行为和改善合金抗高温氧化性能的方法，综述了近年来国内外TiAl合金表面SiO2防护涂层的研究进展，讨论了SiO2涂层的制备方法和原理、高温氧化行为、氧化膜结构及其防护机理，并展望了未来SiO2防护涂层的发展趋势。

Abstract:: Due to low density, high specific strength, and good creep resistance, TiAl alloy has been considered as the high-temperature structure candidates in aerospace and automotive industries. However, the poor high-temperature oxidation resistance limits its applications. The pure SiO2 coating with compact structure, good thermal and chemical stability can effectively improve the high temperature oxidation resistance of TiAl alloy. However, there are some issues when the SiO2 coating with simplified structure is exposed to air at high temperature for long-term, such as the large difference in the thermal expansion coefficients between SiO2 coating and TiAl substrate, and poor stability of the coating and substrate interface. To deal with these issues, SiO2 composite coating emerges, including the introduction of intermediate layer between the SiO2 coating and TiAl substrate, preparation of glass ceramic-based composite coating using the SiO2 coating as the intermediate layer. This paper briefly introduces the oxidation behavior of TiAl alloy and the methods to improve the oxidation resistance of TiAl alloy. The research progress of the silica-based protective coating at home and abroad was reviewed. The preparation methods and principles, high temperature oxidation behavior, structure of oxide scale and protective mechanism of silica-based coatings were discussed. The development trend of silica-based coatings on TiAl alloy in the future was prospected.