钛合金高温防氧化玻璃-陶瓷涂料的制备及表征

摘要

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.%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. Al2 O3, 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.