镀锌钢铈盐转化膜硅酸钠封闭后的耐蚀性能  

Effect of Post-Sealing with Aqueous Solution of Sodium Silicate on Corrosion Resistance of Cerium-Salt Conversion Coating of Galvanized Steel

作　　者：史立平[1] 郭瑞光[1] 

机构地区：[1]西安建筑科技大学西北水资源与环境生态教育部重点实验室,陕西西安710055

出　　处：《材料保护》2013年第6期15-17,6,共3页Materials Protection

基　　金：国家自然科学基金项目(20976143);教育部高等学校博士学科点专项科研基金(20096120110007)资助

摘　　要：为进一步提高镀锌钢铈盐转化膜的耐蚀性能,采用硅酸钠溶液对其封闭处理,优化封闭条件,并采用扫描电镜(SEM)、能谱、中性盐雾加速腐蚀测试和电化学测试研究了封闭前后试片的形貌、成分及耐蚀性。结果表明:最优封闭条件为10 g/L硅酸钠,pH值11.5,温度35℃,时间5 min;硅酸钠溶液封闭处理后,铈盐转化膜表面裂纹消失,膜层连续完整,耐中性盐雾腐蚀时间从封闭前的24 h提高到72 h,腐蚀电流密度从4.64μA/cm2降低到1.51μA/cm2,耐蚀性大大提高。Cerium-salt conversion coating on galvanized steel was post sealed with sodium silicate solution so as to further improve its corrosion resistance.The condition for post-sealing was optimized,and the morphology,composition as well as corrosion resistance of the cerium-salt conversion coatings before and after post-sealing were analyzed with a scanning electron microscope,an energy dispersive spectrometer,a neutral salt-spray accelerating corrosion test rig,and an electrochemical test rig.Results showed that the optimal concentration of the post-sealing fluid was 10 g/L sodium silicate,and the optimal post-sealing condition was suggested as a pH value of 11.5,a temperature of 35 ℃,and a duration of 5 min.The cerium-salt conversion coating after post-sealing treatment was continuous,compact and free of cracks,and possessed greatly improved corrosion resistance.Namely,after post-sealing treatment,the endurance of the cerium-salt conversion coating against neutral salt-spray rose from 24 h to 72 h,and its corrosion current density declined from 4.64 μA/cm2 to 1.51 μA/cm2.

关 键 词：封闭 铈盐转化膜 镀锌钢 硅酸钠 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]