硅酸钠对模拟汽车冷却液中AM60镁合金的缓蚀作用研究  

Corrosion Inhibition Effect of Sodium Silicate on AM60 Magnesium Alloy in Simulated Vehicle Coolant

作　　者：文家新[1,2] 何建新[2] 王莎[2] 许雯婷[2] 

机构地区：[1]重庆工业职业技术学院化学与制药工程学院,重庆401120 [2]重庆大学化学化工学院,重庆400044

出　　处：《表面技术》2016年第12期62-67,共6页Surface Technology

基　　金：重庆市教委资助项目(KJ2217)~~

摘　　要：目的了解在模拟汽车冷却液介质中,Na_2SiO_3对AM60镁合金的缓蚀作用和缓蚀机理。方法通过极化曲线、电化学阻抗谱方法等电化学方法研究了Na_2SiO_3对AM60镁合金在模拟汽车冷却液中的缓蚀性能,考察了Na_2SiO_3浓度、模拟冷却液温度和浸泡时间对缓蚀效率的影响,并对缓蚀机理进行了探讨。结果 Na_2SiO_3浓度对其缓蚀效率影响较大,其最佳浓度为0.8 mmol/L,此时缓蚀效率为95.87%。冷却液在高温(80℃)时,Na_2SiO_3的缓蚀效率为36.08%,也能对AM60镁合金提供一定的缓蚀保护作用。浸泡初期,Na_2SiO_3对AM60镁合金电极的缓蚀效率为17.47%,浸泡10 h后可达72.38%。结论在模拟汽车冷却液中,当Na_2SiO_3的浓度为0.8 mmol/L时其缓蚀效率最高,且其缓蚀效率随介质温度的升高而降低,随浸泡时间的增加而增大。Na_2SiO_3表现为阳极型缓蚀剂的特征,缓蚀机理可解释为Si O32-能与腐蚀产生的Mg2+生成难溶性的Mg Si O3化合物,生成的Mg Si O3沉积于合金表面形成一层保护膜,从而阻滞了金属的进一步离子化。The work aims to study the corrosion inhibition effect and mechanism of sodium silicate on AM60 magnesium alloy in simulated vehicle coolant medium. The corrosion inhibition effect of sodium silicate on AM60 magnesium alloy in simulated vehicle coolant medium was studied by means of electrochemical methods including polarization curves and electrochemical impedance spectroscopy（EIS）. Effects of sodium silicate concentration, simulated coolant temperature and im-mersion time on corrosion inhibition efficiency were inspected. The corrosion inhibition mechanism of sodium silicate was also discussed. Concentration of Na_2SiO_3 had great influence on corrosion inhibition efficiency, and its optimumconcentration was 0.8 mmol/L and the corrosion inhibition efficiency of sodium silicate was 95.87%. Inhibition efficiency of the sodium silicate was up to 36.08% at high temperature（80 ℃） in the simulated coolant. Hence the sodium silicate provided inhibition protection on AM60 magnesium alloy. At the early stage of immersion, corrosion inhibition efficiency of Na_2SiO_3 on AM60 magnesium alloy was 17.47% and then amounted to 72.38% after 10 hours. When concentration of the sodium silicate is 0.8 mmol/L, the corrosion inhibition efficiency is the highest. It decreases as the medium temperature increases and increases as the immersion time in the simulated coolant medium increases. The sodium silicate acts as an anodic type inhibitor, and the corrosion inhibition mechanism of sodium silicate can be interpreted as the fact that insoluble compound of Mg Si O3 can be generated by the reaction of Si O32- with Mg2＋（produced by corrosion）. Mg Si O3 deposites on the surface of alloy and forms a layer of protective film, thus inhibiting further metal ionization.

关 键 词：AM60镁合金 模拟汽车冷却液 硅酸钠 缓蚀作用 极化曲线 电化学阻抗谱 

分 类 号：TG174[金属学及工艺—金属表面处理]