γ-TiAl合金表面Al-Y梯度涂层在850℃硫酸盐中的热腐蚀行为  

Hot Corrosion Behavior of Al-Y Gradient Coating on γ-TiAl Alloy in Sulfate at 850℃

作　　者：李姗 梁文萍[1] 缪强[1] 丁铮[1] 王旭[1] 

机构地区：[1]南京航空航天大学材料科学与技术学院,江苏南京211106

出　　处：《热处理》2018年第1期1-6,共6页Heat Treatment

基　　金：国家自然科学基金项目(51474131);江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：为了提高γ-TiAl合金的耐腐蚀性,采用磁控溅射技术在其表面制备了Al-Y梯度涂层。利用SEM、EDS和XRD分析了涂层的表面形貌、元素分布及相组成。研究了涂层在850℃Na_2SO_4中的热腐蚀行为,并对其腐蚀机制进行了分析。结果表明:Al-Y梯度涂层由沉积层和扩散层组成,厚度约为55μm,表面致密,无明显的孔洞和裂纹,由表及里Al、Y、Ti元素呈梯度分布;Al-Y梯度涂层表面在850℃Na_2SO_4中生成了Al_2O_3、Y_2O_3等氧化物保护层;涂层中Y元素的存在能阻止S元素从界面薄弱处侵入基体,涂层中形成的Y_3Al_5O_(12)相能有效提高耐腐蚀氧化层与基体之间的结合力。Al-Y梯度涂层在850℃Na_2SO_4中具有较好的抗热腐蚀性能。In order to improve the corrosion resistance of γ-TiAl alloy, Al-Y gradient coating was prepared on its surface by magnetron sputtering. The mierostructure, element distribution and phase constituents of the coating were analyzed by means of SEM, EDS and XRD. The hot corrosion behavior of the Al-Y gradient coating in Na2SO4 at 850 ℃ and the mechanism whereby the coating underwent corrosion were investigated. The results were that ： the A1-Y gradient coating consisted of deposition layer and diffusion layer, and was about 55μm in thickness, the surface of Al-Y gradient coating was dense and had no obvious holes and cracks, and the elements such as Al, Y, Ti were in the form of a gradient distribution from the surface to the inner; oxides such as Al2O3 and Y2O3 that served the function of protection were formed on the coating in NaESO4 at 850 ℃ ; Y element present in the coating can hinder S element from entering into the basis metal through the weak interface. On the other hand, the Y3Al5O12 phase formed in the coating can effectively improve the adhesion between the corrosion-resistant oxide layer and the substrate, and, as a result, the Al-Y gradient coating exhibited an excellent hot corrosion resistance in Na2SO4 at 850 ℃.

关 键 词：Γ-TIAL合金 A1-Y梯度涂层 热腐蚀 机制 

分 类 号：TG174.444[金属学及工艺—金属表面处理]