Galfan镀层镧盐转化膜的制备和耐蚀性能研究  

Growth and Corrosion Resistance of Lanthanum Conversion Coating on Galfan Steel

作　　者：吴晓晓[1] 孔纲[1] 孙子文[1] 车淳山[1] 

机构地区：[1]华南理工大学材料科学与工程学院,广东广州510640

出　　处：《中国稀土学报》2015年第5期609-614,共6页Journal of the Chinese Society of Rare Earths

基　　金：国际铅锌研究组织资助项目(ILZRO/IZA/CN201212);中央高校基本科研业务费项目(2012ZM0011);广东省教育部产学研结合项目(2012B091100312)资助

摘　　要：将热浸镀Galfan钢板浸入含有20 g·L-1La(NO3)3·6H2O,10 m L·L-1H2O2,0.1 g·L-1Na F的处理液中,在70℃下处理10 s^30 min,从而在其表面获得镧盐转化膜。采用扫描电子显微镜(SEM)观察膜层的微观形貌,能谱仪(EDS)分析膜层的化学成分。采用中性盐雾试验和电化学极化曲线来研究膜层的耐蚀性能。结果表明,镧盐转化膜在晶界或相界等活性区域优先成膜并迅速生长,膜层形成不均匀。随着处理时间的延长,镧盐转化膜逐渐增厚,膜层的裂纹变多、扩大并脱落;膜层主要由Zn,Al,O和La元素组成。与未处理的热浸镀Galfan镀层相比,镧盐转化膜的腐蚀电流密度显著降低,极化电阻显著提高,基体耐腐蚀性能明显提高。Lanthanum conversion coating was obtained on hot-dip Galfan queous solution containing 20 g.L - 1 La （ NO3 ） 3 ·6 H2 O, 10 mL·L - 1 H2O2 min. The micro-structure of the coating was observed by SEM. The chemi steel by immersion the sample into an a- , 0.1 g.L-1 NaF, at cal composition of the 70 ℃ forlO s-30 coating was investi- gated by EDS. The corrosion resistance of lanthanum conversion coating was assessed by neutral salt spray tests （NSS） and electrochemical polarization curve. The results showed that lanthanum conversion coating filmed on the grain boundaries and phase boundaries and other active region in priority grew rapidly, and coating was nonuni- form. The thickness of the coating increased and the cracks in the film was wide, and filled off with the treatment time prolonging. Lanthanum conversion coating was composed of Zn, A1, La and O. In comparison with the blank Galfan steel, when the corrosion current density of lanthanum conversion coating decreased, the polarization resist- ance of coating increased significantly. The corrosion resistance of lanthanum conversion was remarkably improved.

关 键 词：GALFAN 镧盐转化膜 微观形貌 耐腐蚀性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]