核蒸汽发生器用含Ti缓蚀添加剂高压釜暴露实验及表面分析  

Study of Inhibitor Containing Ti Through Exposed Experiment and Analysis of Surface Film for Nuclear Steam Generator

作　　者：徐祺[1] 黄新泉[1] 苏兴万[1] 马韦刚[1] 

机构地区：[1]中国核动力研究设计院核燃料及材料国家级重点实验室,成都600041

出　　处：《核动力工程》2004年第6期550-554,570,共6页Nuclear Power Engineering

摘　　要：近来的研究表明,TiO2缓蚀添加剂能有效减缓蒸汽发生器传热管的应力腐蚀开裂(SCC)和晶间腐蚀(IGA)等局部腐蚀。本工作以不锈钢为试验材料,对含Ti缓蚀添加剂在高温浓碱环境中缓解应力腐蚀开裂的能力进行了初步的研究。高压釜暴露实验表明,在288℃、50%NaOH溶液中浸泡一周,含Ti缓蚀添加剂表现出较好的缓蚀效果。其中,锐钛矿、金红石型TiO2的作用要好于钛酸丁酯;但在相同环境下长时间(两周以上)浸泡,其抑制应力腐蚀开裂的能力并不显著。用扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等手段进行进一步的表面分析,研究了腐蚀产物形貌及结构,并探讨了合金在碱性环境中的去合金化趋势。XPS纵深图谱表明锐钛矿型TiO2能明显抑制合金的去合金化趋势,防止裂纹沿贫Cr的晶界发展,从而起到缓解腐蚀的作用。Corrosion of construction material in high temperature water is one of important problems for nuclear reactors. Latest researches show that TiO2 inhabiting species can alleviate local corrosion, such as Stress Corrosion Cracking (SCC) and Inter-granular Attack (IGA) of steam generator tubes, prolong the life of SG tube. The result of high temperature exposed experiments shows that TiO2 have positive effect. No SCC was found in 0Cr18Ni10Ti stainless steel after exposure to the 50% caustic solution with inhibitor containing Ti at 288℃ for 1 week. Among them, Rutile and Anatase are more effective than tetrabutyl titanate. But dur-ing a longer time (above 2 weeks) of experiment, the inhibitors containing Ti can not prevent SCC. SEM, XRD, XPS were used to analyze the chemical composition and construction of the film formed on the surface of the specimen, and the issue of dealloying was discussed. Depth sputtered XPS figure shows that Anatase can prevent dealloying and control the development of crack along inter-granular. TiO2 inhabiting species is a new type granular inhibitor, and its application is being paid close attention.

关 键 词：不锈钢 应力腐蚀开裂 含Ti缓蚀剂 碱溶液 去合金化 

分 类 号：TG174.4[金属学及工艺—金属表面处理]