Insights into the mechanism of Mo protecting CoCrFeNi HEA from pitting corrosion-A quantitative modelling study on passivation and repassivation processes  

作　　者：Jing Dai Hao Feng Hua-Bing Li Hong-Chun Zhu Shu-Cai Zhang Jin-Dong Qu Tong He Zhou-Hua Jiang Tao Zhang 

机构地区：[1]School of Metallurgy,Northeastern University,Shenyang 110819,China [2]Key Laboratory for Ecological Metallurgy of Multimetallic Ores(Ministry of Education),Northeastern University,Shenyang 110819,China [3]Analysis and Testing Centre,Northeastern University,Shenyang 110819,China [4]School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China

出　　处：《Journal of Materials Science & Technology》2024年第15期152-164,共13页材料科学技术（英文版）

基　　金：funded by the National Natural Science Foun-dation of China(Grant Nos.U1960203,52004060,52325406,and 52174308);Science Fund for Distinguished Young Scholars of Liaon-ing Province(Grant No.2023JH6/100500008);Fundamental Re-search Funds for the Central Universities(Grant Nos.N2125017 and N2225031).Special thanks are due to the instrumental analysis from the Analytical and Testing Centre,Northeastern University.

摘　　要：Mo has been widely reported as a conducive element for the corrosion resistance of massive alloy sys-tems.However,the mechanism of Mo optimizing the corrosion resistance is complicated,and in-depth studies are still required.The present work comprehensively and quantitatively studied the critical influ-ences of Mo on the passivation and repassivation behavior of CoCrFeNi HEA based on the dissolution-diffusion-deposition model proposed in our previous work.The experimental results indicated that Mo remarkably eliminated the metastable pitting corrosion,significantly improved the breakdown potential and perfectly protected the CoCrFeNiMo_(0.2)HEA from pitting corrosion.The modelling and X-ray photo-electron spectroscopy(XPS)results both show that in the passivation process,MoO_(2)was the last product to deposit,thereby existing in the outer layer of the passive film.Mo addition increased the Cr content by weakening the deposition of Fe_(2)O_(3)and Fe_(3)O_(4)and also improved the Cr_(2)O_(3)/Cr(OH)3 ratio by promot-ing deprotonation of Cr(OH)_(3),thus enhancing the quality of passive film.Besides,when pitting corrosion occurred,MoO_(2),MoO_(3),and FeMoO_(4)were the first products to deposit and accelerated the repassivation process of HEA by timely covering the matrix in the pit cavity,thereby preventing further corrosion of the matrix.

关 键 词：High entropy alloy Modelling studies Passive films Pitting corrosion Repassivation process 

分 类 号：TG172[金属学及工艺—金属表面处理]