Y_2O_3-ZrO_2热障涂层的热腐蚀行为

Hot corrosion behavior of Y_2O_3-ZrO_2 thermal barrier coating

热障涂层在腐蚀性熔盐中易发生腐蚀,影响其使用的安全性。为此,研究Y_2O_3-ZrO_2热障涂层在900℃下、不同比例Na_2SO_4/V_2O_5混合盐中腐蚀20h的热腐蚀行为。利用扫描电镜观察热障涂层在不同熔盐中的腐蚀形貌。研究表明,在Na_2SO_4盐中,热障涂层未发生腐蚀,随着V_2O_5含量的增加,腐蚀产物由块状向棒状、束状变化;在V_2O_5盐中腐蚀时,腐蚀产物呈颗粒状。经XRD分析及m相定量计算可知,在Na_2SO_4盐中腐蚀,涂层中m相几乎为0,且未检测到腐蚀产物;随着V_2O_5含量的增加,m相含量也相应增加,但增加幅度不大,腐蚀产物均为YVO_4。

This paper is aimed at eliminating the corrosion more likely to occur in thermal barrier coatings in a corrosion environment,with a negative effect on the performance of thermal barrier coatings.The solution is effected by investigating the hot corrosion behavior of Y2O3-ZrO2 thermal barrier coatings in the mixed Na2SO4/V2O5 molten salt at 900 ℃ for 20 h.The observation of the top-view corrosion morphologies using the scanning electron microscopy （SEM） finds that no corrosion process is seen thermal barrier coating in the Na2SO4 molten salt;and corrosion products experience changes from bulk-like to rod-like and needle-like shape following an increase in V2O5 content;and particle-like corrosion products are found when corrosion occurs in V2O5 molten salt.X-ray diffraction patterns and quantitative calculation of monoclinic phase of ZrO2 show that the m phase content is approximate to 0 if thermal barrier coating corrodes in Na2SO4 molten salt,without detecting corrosion product;and an increase in V2O5 content is followed by an increase in the m phase content,but with a smaller increase range,leaving all the corrosion products in the structures of YVO4.