不同水化学条件下800合金传热管的均匀腐蚀性能  

General Corrosion Behavior of Alloy 800 Steam Generator Tube under Different Water Chemistry Conditions

作　　者：刘晓强 刘冀 孙伟[2] 张志明[2] 孟凡江 王俭秋[2] 石秀强 LIU Xiaoqiang;LIU Ji;SUN Wei;ZHANG Zhiming;MENG Fanjiang;WANG Jianqiu;SHI Xiuqiang(Shanghai Nuclear Engineering Research and Design Institute,Shanghai 200233,China;CAS Key Laboratory for Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]上海核工程研究设计院有限公司,上海200233 [2]中科院核用材料与安全评价重点实验室,中国科学院金属研究所,沈阳110016

出　　处：《腐蚀与防护》2020年第9期20-26,共7页Corrosion & Protection

基　　金：大型先进压水堆核电重大专项(2018ZX06001001)。

摘　　要：通过高温高压循环水均匀腐蚀试验及电化学测试方法,研究了800合金传热管在300℃、10 MPa、去离子水、溶氧(DO=2mg/L)以及溶氢(DH=2.7mg/L)条件下的均匀腐蚀速率及表面氧化膜特征。结果表明,800合金在DO及DH这两种条件下的均匀腐蚀速率均很低,分别为5.6μm/a和1.2μm/a。在这两种环境中,试样氧化膜均为内外双层结构,内层连续而致密,外层主要由颗粒状氧化物组成。800合金在正常运行环境(DH工况)中,具有较稳定的电化学特征和明显的钝化区;而在含氧环境中(DO=2mg/L),随着时间的延长,在96h后,开路电位会发生明显的升高,开路电位由-0.39V(vs.SHE)逐渐升高至0.42V(vs.SHE),呈现出无明显的钝化区,但自腐蚀电流密度未有明显提高,且阻抗值较大,说明合金表面仍具有较稳定的氧化膜结构。Through high temperature and high pressure circulating water test and electrochemical test,the uniform corrosion rate and surface oxide film characteristics of alloy 800 tube were studied under the conditions of 300℃,10 MPa,deionized water,2 mg/L DO(dissolved oxygen)and 2.7 mg/L DH(dissolved hydrogen).The results showed that the uniform corrosion rates of alloy 800 under DO and DH conditions were very low,which were5.6μm/a and 1.2μm/a respectively.The oxide films under these two conditions were both composed of two layers.The inner layer of the oxide film was continuous and dense,while the outer layer was mainly composed of granular oxide.In the normal operation environment(DH working condition),alloy 800 presented more stable electrochemical characteristics and obvious passivation zone;while in the oxygen containing environment(DO=2 mg/L),the open circuit potential increased significantly after 96 h,increased from-0.39 V(vs.SHE)to 0.42 V(vs.SHE).No obvious passivation was observed,but the self-corrosion current density was not increased and the impedance value was much higher,indicating that the alloy surface still had relatively stable oxide film structure.

关 键 词：800合金 水化学 氧化膜 腐蚀速率 电化学 

分 类 号：TG174[金属学及工艺—金属表面处理]