Hot Corrosion Behavior of SiO_2–Al_2O_3–Glass Composite Coating on Ti–47Al–2Cr–2Nb Alloy: Diffusion Barrier for S and Cl

作     者：Wen-Bo Li Lan-Lan Liu Ying-Fei Yang Sheng-Long Zhu Fu-Hui Wang 

作者机构：Hunan Electric Power Co. Ltd. Institute of Advanced Wear and Corrosion Resistant and Functional Material Jinan University Laboratory of Corrosion and Protection Institute of Metal Research Chinese Academy of Sciences 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2019年第32卷第5期

页      面：599-606页

核心收录：

学科分类：080503[工学-材料加工工程] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0802[工学-机械工程] 0703[理学-化学] 0811[工学-控制科学与工程] 

基　　金：supported by the National Natural Science Foundation of China (Grant No. 51201171) the National High Technology Research and Development Program of China (863 Program, Grant No. 2012AA03A512) 

主　　题：Corrosion Composite coating Ti–47Al–2Cr–2Nb alloy Diffusion 

摘      要：Type Ⅰ hot corrosion behavior of SiO_2-Al_2O_3-glass composite coating based on Ti-47 Al-2 Cr-2 Nb substrate was investigated in the mixture salt of 25 wt%NaCl + 75 wt%Na_2SO_4 at 850 °C. The results showed that there was a bidirectional ion exchange between composite coating and the film of mixed salts, and the sodium ion in the molten salts penetrated into the glass matrix of composite coating, while the potassium ion in the glass matrix dissolved into the molten salts. A decrease in hot corrosion rate was achieved for the coated alloy in comparison with the bared substrate due to the composite coating acting as a diffusion barrier to sulfur and chlorine and preventing the molten salts from diffusing to the coating/alloy interface during the hot corrosion exposure. Additionally, the composite coating decreased the oxygen partial pressure at the coating/alloy interface and promoted the selective oxidation of Al to form a protective Al_2O_3 layer.