氯和氢对新型超高强度Cr12Ni4Mo2Co14钢在酸性环境中电化学腐蚀行为的影响

摘要

采用极化曲线、电化学阻抗和Mott-Schottky等电化学试验研究了酸性环境中Cl-和氢对一种新型超高强度Cr12Ni4Mo2Co14钢电化学腐蚀行为的影响.结果表明:Cl-和氢均对Cr12Ni4Mo2Co14钢的阳极钝化区产生影响,随着Cl-含量和氢含量的增加,点蚀电位负向移动,钝化区间缩短;Cl-通过占据氧空位促进钝化膜中形成Schot-tky空位对,而金属离子空位聚集会引起钝化膜的破坏;与未充氢Cr12Ni4Mo2Co14钢相比,充氢Cr12Ni4Mo2Co14钢中的施主和受主密度均有所提高,导致阳离子空位浓度提高,局部阳离子空位的聚集可诱导钝化膜的击穿.%The electrochemical corrosion behavior of a new kind of ultrahigh strength steel Cr12Ni4Mo2Co14 in acid environment was studied by electrochemical methods of polarization curves testing,electrochemical impedance spectroscopy (EIS) testing and Mott-Schottky testing.Both chloride ion and hydrogen can affect the anode passivation zone of Cr12Ni4Mo2Co14 steel.With the increase of concentrations of chloride ion and hydrogen,the pitting potential moved negatively and the passivation zone was narrowed.The Schottky pairs were formed by chloride ions occupying vacancies of oxygen.Vacancies of metal ions gathered,which broke the passive film.Donor and acceptor densities of hydrogen-charged Cr12Ni4Mo2Co14 steel increased in comparison with those of non hydrogencharged Cr12Ni4Mo2Co14 steel,which increased the concentration of positive ion vacancy.Then the passive film can be broken by the gather of positive ion vacancies at local area.