钛合金高温防氧化玻璃-陶瓷涂料的制备及表征

利用浸涂法在TC4钛合金表面制备了高温防氧化玻璃-陶瓷涂层。采用金相观察(OM)、扫描电镜(SEM)、X射线衍射(XRD)、电子探针分析(EPMA)对其性能进行了表征。该涂料是以硅酸盐玻璃为主体,硅酸钠为粘结剂制备而成的料浆悬浮体。在500～1 000℃的温度范围内,与没有涂层保护的基体相比,在涂层保护下基体的氧化程度至少可减轻85%。研究表明:随温度升高,涂层逐渐熔融,得到一层致密的保护层,涂层中依次出现Al2O3、TiO2、硅酸盐、钛铝、硅铝化合物等物相,使得涂层具有很好的高温流动性和稳定性,有效阻挡了氧气对基体的侵蚀,且涂层对基体的沾污甚微。涂层与基体的热膨胀系数(CTE)失配达到87%,涂层在使用后可以实现完全自剥落。

Preparation and Characterization of Oxidation-Resistant Glass-Ceramic Coating for Titanium Alloy Used at High Temperature

A glass-ceramic coating used for oxidation-resistant at high temperature was prepared on TC4 titanium alloy by a slurry-dipping technique.The properties of as-obtained coating were characterized by OM,SEM,XRD and EPMA.The coating was a slurry suspension consisting of silicate glass powder and sodium silicate as binder.At temperature ranging from 500 ℃ to 1 000 ℃,the oxidation of the coated specimens could be reduced by at least 85% comparing with that of the bare specimens.The results demonstrated that the coating become a melted layer with the increase of the temperature forming a densed protective layer.Al2O3,TiO2,silicate,TiAl and SiAl compounds appeared successively at the elevated temperature,which ensured good high temperature fluidity and stability of as-obtained coating,to protect alloy well against oxidation and only a tiny pollution to the alloy.The coating could be feeled off completely during cooling,considering 87% CTE mismatch between the coating and the titanium alloy.