Chenglong Zhang, M. Zhu, Yongfeng Yuan, Shao-yi Guo, G. Wei
{"title":"pH对CoCrNi MEA在Na2CO3/NaHCO3溶液中交流腐蚀行为的影响","authors":"Chenglong Zhang, M. Zhu, Yongfeng Yuan, Shao-yi Guo, G. Wei","doi":"10.1080/1478422X.2023.2247883","DOIUrl":null,"url":null,"abstract":"ABSTRACT The corrosion behaviour and mechanism of CoCrNi medium-entropy alloy (MEA) imposed by alternating current (AC) in HCO3 −/CO3 2− solution with various pH were systematically investigated via a series of corrosion tests. The results showed that with the augment of pH value, the polarisation resistance of the MEA decreased significantly, Ep shifted negatively, and ipI value increased, as well as corrosion rate was enhanced, revealing that the corrosion resistance was weakened. As solution pH increased, the formation of secondary passivation zone became easier, which may be attributed to the reaction conversion process of Cr(III) to Cr(VI) species. Moreover, the increase in pH led to an increase in defect density and a thinning of passivation film, facilitating the corrosion of the MEA. AC interference accelerated the ion exchange process and promoted the formation possibility of stable pitting. Higher iAC and pH inhibited the repassivation of metastable pitting, and increased the pitting susceptibility. Highlights The effect of pH on the corrosion behaviour of CoCrNi MEA with imposed AC was clarified. High pH and iAC accelerated the nucleation and growth of metastable pits. With increased pH and iAC, the stability and protective ability of passive film were weakened. The secondary passivation of the MEA was mainly due to the conversion of Cr(III) to Cr(VI) species. GRAPHICAL ABSTRACT","PeriodicalId":10711,"journal":{"name":"Corrosion Engineering, Science and Technology","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2023-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Effect of pH on corrosion behaviour of CoCrNi MEA imposed by alternating current in Na2CO3/NaHCO3 solution\",\"authors\":\"Chenglong Zhang, M. Zhu, Yongfeng Yuan, Shao-yi Guo, G. Wei\",\"doi\":\"10.1080/1478422X.2023.2247883\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"ABSTRACT The corrosion behaviour and mechanism of CoCrNi medium-entropy alloy (MEA) imposed by alternating current (AC) in HCO3 −/CO3 2− solution with various pH were systematically investigated via a series of corrosion tests. The results showed that with the augment of pH value, the polarisation resistance of the MEA decreased significantly, Ep shifted negatively, and ipI value increased, as well as corrosion rate was enhanced, revealing that the corrosion resistance was weakened. As solution pH increased, the formation of secondary passivation zone became easier, which may be attributed to the reaction conversion process of Cr(III) to Cr(VI) species. Moreover, the increase in pH led to an increase in defect density and a thinning of passivation film, facilitating the corrosion of the MEA. AC interference accelerated the ion exchange process and promoted the formation possibility of stable pitting. Higher iAC and pH inhibited the repassivation of metastable pitting, and increased the pitting susceptibility. Highlights The effect of pH on the corrosion behaviour of CoCrNi MEA with imposed AC was clarified. High pH and iAC accelerated the nucleation and growth of metastable pits. With increased pH and iAC, the stability and protective ability of passive film were weakened. The secondary passivation of the MEA was mainly due to the conversion of Cr(III) to Cr(VI) species. GRAPHICAL ABSTRACT\",\"PeriodicalId\":10711,\"journal\":{\"name\":\"Corrosion Engineering, Science and Technology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.5000,\"publicationDate\":\"2023-08-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Corrosion Engineering, Science and Technology\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://doi.org/10.1080/1478422X.2023.2247883\",\"RegionNum\":4,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Corrosion Engineering, Science and Technology","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1080/1478422X.2023.2247883","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
Effect of pH on corrosion behaviour of CoCrNi MEA imposed by alternating current in Na2CO3/NaHCO3 solution
ABSTRACT The corrosion behaviour and mechanism of CoCrNi medium-entropy alloy (MEA) imposed by alternating current (AC) in HCO3 −/CO3 2− solution with various pH were systematically investigated via a series of corrosion tests. The results showed that with the augment of pH value, the polarisation resistance of the MEA decreased significantly, Ep shifted negatively, and ipI value increased, as well as corrosion rate was enhanced, revealing that the corrosion resistance was weakened. As solution pH increased, the formation of secondary passivation zone became easier, which may be attributed to the reaction conversion process of Cr(III) to Cr(VI) species. Moreover, the increase in pH led to an increase in defect density and a thinning of passivation film, facilitating the corrosion of the MEA. AC interference accelerated the ion exchange process and promoted the formation possibility of stable pitting. Higher iAC and pH inhibited the repassivation of metastable pitting, and increased the pitting susceptibility. Highlights The effect of pH on the corrosion behaviour of CoCrNi MEA with imposed AC was clarified. High pH and iAC accelerated the nucleation and growth of metastable pits. With increased pH and iAC, the stability and protective ability of passive film were weakened. The secondary passivation of the MEA was mainly due to the conversion of Cr(III) to Cr(VI) species. GRAPHICAL ABSTRACT
期刊介绍:
Corrosion Engineering, Science and Technology provides broad international coverage of research and practice in corrosion processes and corrosion control. Peer-reviewed contributions address all aspects of corrosion engineering and corrosion science; there is strong emphasis on effective design and materials selection to combat corrosion and the journal carries failure case studies to further knowledge in these areas.