三种有机物对LY12CZ铝合金在酸性溶液中的缓蚀行为研究

摘要

The inhibiting effect of three organic compounds on the corrosion of LY12CZ aluminum alloy in 0. 5M H2SO4 solution was investigated. The organic compounds are 2-mercaptobenzoxazole (MBIH), benzotriazole (BTA) and 8-hydroxy-quinoline(8Q). The inhibiting effect to the corrosion dynamics of LY12CZ aluminum alloy in 0. 5M H2SO4 solution was evaluated by using mass loss method and the corrosion morphology was observed by using optical microscopy (OM), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to study the inhibiting mechanism. The results show that MBIH, BTA and 8Q all provide anti-corrosion protection for LY12CZ aluminum alloy by forming a thin organic layer of insoluble complexes on the surface of the alloy. Their in-hibitive properties are given by the following order: MBIH>BTA>8Q. MBIH and BTA provide anti-corrosion protection by absorbing selectively on the corrosion active intermetallic zones and suppressing the cathode processes of corrosion reaction. The whole surface of the alloy was absorbed by 8Q to form chelate 8Q complexes, but the absorbed layer was destroyed as the anode dissolution.%本工作选取了2-巯基苯并噻唑(MBIH)、苯并三氮唑(BTA)和8-羟基喹啉(8Q)等几种典型的缓蚀剂,研究了其对LY12CZ铝合金在酸性溶液中的缓蚀效果及机理.通过腐蚀失重法研究了三种缓蚀剂对LY12CZ铝合金在酸性溶液中腐蚀动力学的影响.利用光学显微镜(OM)、场发射扫描电子显微镜(FE-SEM)及能谱(EDS)等对合金组织和腐蚀形貌进行观察;利用动电位极化、交流阻抗谱(EIS)等研究了铝合金在含有这三种缓蚀剂溶液中的电化学特性,并对其缓蚀机理进行了探讨.结果表明:三种有机物均能在酸性溶液中对LY12CZ铝合金起到缓蚀作用;缓蚀效果MBIH>BTA>8Q.MBIH和BTA能够选择性地吸附在LY12CZ铝合金表面S相残留物及杂质相颗粒表面,形成难溶物,抑制腐蚀反应的阴极过程,从而为LY12CZ铝合金在酸性溶液中的腐蚀提供良好的保护.8Q能够吸附在整个铝合金的表面,但随着阳极溶解的进行,吸附层遭到破坏,从而影响了缓蚀效果.