AM355不锈钢在酸性溶液中的腐蚀电化学行为
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摘要
结合腐蚀形貌,通过极化曲线、交流阻抗谱(EIS)和莫特肖特基(MS)曲线的测定,分析了溶液pH值对AM355不锈钢腐蚀电化学行为的影响。结果表明:随溶液pH值的减小,腐蚀电位正移,腐蚀电流密度增大,致钝电位发生了正移,致钝电流密度、维钝电流密度增大。钝化膜由铬氧化物和铁氧化物组成,酸性增加使得铁氧化物施主浓度增大,钝化膜表面吸附氢离子电荷密度增加。钝化膜的厚度及其电阻随pH值的减小而减小,钝化膜更容易被破坏,酸性达到一定程度,钝化膜局部区域优先腐蚀。溶液pH值减小,AM355在溶液中保持自钝化性能降低,材料的腐蚀速率增加。
Effect of pH value on the electrochemical corrosion behaviors of AM355 stainless steel was investigated by means of polarization,electrochemical impedance spectroscopy(EIS),Mott-Schottky(MS)and scanning electron microscope(SEM).Results show that both of the corrosion potential and the initiating passive potential move toward positive direction as pH decreases.Additionally,the current densities of corrosion,passivity-initiating and passivity-maintaining increase simultaneously.The passive film is composed of Cr and Fe oxides.The decrease of pH leads to the increment of both donor density of Fe oxide and the H+absorption density on the film surface.The thickness and the resistance of passive film reduce as pH declines.The passive film will be locally destroyed when the pH decrease to a certain extent.In the high concentration acid solution,the passive film is more easily destroyed and the self-passivation ability is weakened,thereby the steel corrosion rate accelerates.
Effect of pH value on the electrochemical corrosion behaviors of AM355 stainless steel was investigated by means of polarization,electrochemical impedance spectroscopy(EIS),Mott-Schottky(MS)and scanning electron microscope(SEM).Results show that both of the corrosion potential and the initiating passive potential move toward positive direction as pH decreases.Additionally,the current densities of corrosion,passivity-initiating and passivity-maintaining increase simultaneously.The passive film is composed of Cr and Fe oxides.The decrease of pH leads to the increment of both donor density of Fe oxide and the H+absorption density on the film surface.The thickness and the resistance of passive film reduce as pH declines.The passive film will be locally destroyed when the pH decrease to a certain extent.In the high concentration acid solution,the passive film is more easily destroyed and the self-passivation ability is weakened,thereby the steel corrosion rate accelerates.
引文
[1]孙永庆,梁剑雄,杨志勇,等.热处理工艺对AM355不锈钢力学性能的影响及机理[J].钢铁,2014,49(9):77~80.
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[11]崔晓莉,江志裕.半导体电极的平带电位及其物理意义[C].第十三届全国太阳能光化学与光催化学术会议,武汉,2012年10月.第十三届全国太阳能光化学与光催化学术会议学术论文集,北京:中国化学会,2012,52~53.
[12]孔德生,李亮.电容测量研究铬表面氧化膜的半导体性能[J].物理化学学报,2004,20(6):631~636.
[2]胡家齐,刘荣佩,等.调整处理对AM355不锈钢微观组织与力学性能的影响[J].金属热处理,2015,40(6):91~96.
[3]孙永庆,梁剑雄,等.化学成分和热处理对AM355不锈钢组织和力学性能的影响[J].钢铁,2013,48(5):68~71.
[4]J.Warren,D.Y.Wei.The Low Cycle Fatigue Behavior of the Controlled Transformation Stainless Steel Alloy AM355at 121,204and 315℃[J].Materials Science and Engineering A,2008,475(1):148~156.
[5]吕祥鸿,谢俊峰,等.超级13Cr马氏体不锈钢在鲜酸中的腐蚀行为[J].材料科学与工程学报,2014,32(3):318~323.
[6]曹楚南.腐蚀电化学原理[M].第3版.北京:化学工业出版,2008,176.
[7]张晖,李成涛,宋利君,等.pH对316L不锈钢电化学性能的影响[J].腐蚀与防护,2013,34(7):593~596.
[8]S.Ningshen,U.Kamachi Mudali,V.K.Mittal,H.S.Khatak.Semiconducting and Passive Film Properties of Nitrogen-containing type 316LN Stainless Steels[J].Corrosion Science,2007,49(2):481~496.
[9]陈长风,姜瑞景,张国安,郑树起.双极性半导体钝化膜空间电荷电容分析[J].物理化学学报,2009,25(3):463~469.
[10]张福祥,吕祥鸿,等.不同腐蚀条件下高强15Cr马氏体不锈钢表面状态表征[J].材料科学与工程学报,2015,33(6):804~809.
[11]崔晓莉,江志裕.半导体电极的平带电位及其物理意义[C].第十三届全国太阳能光化学与光催化学术会议,武汉,2012年10月.第十三届全国太阳能光化学与光催化学术会议学术论文集,北京:中国化学会,2012,52~53.
[12]孔德生,李亮.电容测量研究铬表面氧化膜的半导体性能[J].物理化学学报,2004,20(6):631~636.