稀土硅酸盐陶瓷高温水蒸汽腐蚀研究进展

Research Progress on High-Temperature Water Vapor Corrosion of Rare Earth Silicate Ceramics

摘要:

稀土硅酸盐陶瓷具有耐高温和力学性能优异等特点，目前被认为是最具应用前景的碳化硅纤维增强碳化硅（SiC_f/SiC）的环境障涂层材料。然而，航空发动机苛刻的服役环境要求稀土硅酸盐环境障涂层材料需要具备优异的抗水蒸汽腐蚀性能。因此，稀土硅酸盐的抗水蒸汽腐蚀性能的研究得到了广泛地关注。基于对稀土硅酸盐陶瓷高温水蒸汽腐蚀研究进展的系统总结，探讨了稀土元素种类、稀土硅酸盐种类、组织状态、腐蚀温度、腐蚀时长及水蒸汽流速等因素对稀土硅酸盐水蒸汽腐蚀行为的影响机理。稀土单硅酸盐抗水蒸汽腐蚀性能优于稀土双硅酸盐，而稀土双硅酸盐的热膨胀系数较低，具有更好的抗裂纹扩展能力。稀土元素离子半径较小的稀土硅酸盐展现出较为优异的抗水蒸汽腐蚀性能，在制备多组元掺杂稀土硅酸盐时，可引入离子半径小的稀土元素以提升抗水蒸汽腐蚀性能。通过稀土硅酸盐的疏水性可以预测抗水蒸汽腐蚀性能，受孔隙率的影响，稀土硅酸盐致密陶瓷块体的抗水蒸汽腐蚀性能通常优于涂层，但通过优化制备方法获得的高度致密涂层的抗水蒸汽腐蚀性能得到大幅提升。通常更高的腐蚀温度和时长、更大的水蒸汽流速和含量也会导致稀土硅酸盐陶瓷遭受更严重的腐蚀。稀土硅酸盐高温水蒸汽腐蚀行为的探讨，为稀土硅酸盐环境障涂层的发展和应用提供了有益的参考。(专精特新·特殊环境材料服役行为专辑十五之二)

Abstract:

Rare earth silicate ceramics， characterized by their high-temperature resistance， and excellent mechanical properties， are currently considered as the most promising environmental barrier coating materials for silicon carbide fiber-reinforced silicon carbide （SiC_f/SiC）. The harsh service environment of aero-engines necessitates that rare earth silicate environmental barrier coating materials possess excellent resistance to water vapor corrosion. Therefore， the resistance to water vapor corrosion of rare earth silicates has garnered widespread attention from researchers. Based on a systematic summary of the research progress on high-temperature water vapor corrosion of rare earth silicate ceramics， this article discusses the mechanisms by which factors such as the type of rare earth element， the type of rare earth silicate， microstructure， corrosion temperature， corrosion duration， and water vapor flow rate affect the water vapor corrosion behavior of rare earth silicates. Rare earth monosilicates exhibit superior resistance to water vapor corrosion compared to rare earth disilicates， while rare earth disilicates have a lower thermal expansion coefficient and better resistance to crack propagation. Rare earth silicates with smaller ionic radii of rare earth elements demonstrate superior resistance to water vapor corrosion. When preparing multi-component doped rare earth silicates， the introduction of rare earth elements with smaller ionic radii can enhance resistance to water vapor corrosion. The resistance to water vapor corrosion can be predicted based on the hydrophobicity of rare earth silicates. Due to the influence of porosity， the resistance to water vapor corrosion of dense ceramic blocks of rare earth silicates is generally superior to that of coatings， but by optimizing the preparation method to obtain highly dense coatings， their resistance to water vapor corrosion can be significantly improved. Higher corrosion temperature and duration， as well as greater water vapor flow rate and content， usually lead to more severe corrosion of rare earth silicates. Finally， based on the above conclusions， the development direction of high-temperature water vapor corrosion research on rare earth silicates is prospected， aiming to provide useful references for the development and application of rare earth silicate environmental barrier coatings.