氟硅酸盐/氟钛酸铵封闭铈盐转化膜的耐蚀性能  

Corrosion Resistance of Cerium Conversion Coating Sealed with Fluorosilicate/Ammonium Fluorotitanate on Galvanized Steel

作　　者：张震[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》2014年第6期17-19,34,共4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：铈盐转化膜耐蚀性能不足。采用由氟硅酸盐、氟钛酸铵双组分封闭液对镀锌钢铈盐转化膜进行了封闭处理,优选了封闭液的最佳含量及封闭工艺条件。分别采用BM-4XC金相显微镜、FEI-Quanta600环境扫描电镜、INCA能谱仪分析了铈盐转化膜封闭前后的形貌、结构与成分;依据ASTM1B17标准进行了中性盐雾腐蚀,采用PARSTAT227电化学工作站,测试了其在3.5%NaCl溶液中的极化曲线和腐蚀形貌。结果表明:镀锌钢铈盐转化膜封闭后成分从5.80%P,1.96%Fe,64.84%Zn,2.94%Ce和24.46%O变为7.34%P,55.26%Zn,3.67%Ce,33.07%O,0.19%Si和0.47%Ti;腐蚀电位负移30 mV,腐蚀电流密度降低了11.4%;封闭前中性盐雾时间为10 h,封闭后为72 h,耐蚀性能大大提高。A dualcomponent sealing solution consisting of fluorosilicate and ammonium fluorotitanate was adopted to seal the cerium conversion coating on galvanized steel,and the composition of the sealing solution as well as the sealing condition was optimized.An optical microscope,an environmental electron microscope,and an energy dispersive spectrometer were performed to analyse the morphology,microstructure and composition of the cerium conversion coatings before and after sealing treatment.Moreover,neutral salt-spray tests were conducted according to ASTM1B17 standard,and the polarization curves of the conversion coatings in3.5%NaCl solution were measured with an electrochemical workstation.Moreover,the morphologies of the corroded coating surfaces were observed.Results indicated that the cerium conversion coating before sealing treatment consisted of 5.80%P(mass fraction;the same hereafter),1.96%Fe,64.84%Zn,2.94%Ce and 24.46%0,and the one after sealing treatment consisted of7.34%P,55.26%Zn,3.67%Ce,33.07%O,0.19%Si and0.47%Ti.In the meantime,the corrosion potential of the cerium conversion coating after scaling treatment shifted negatively by 30 mV,and its corrosion current density declined by about 11.4%,while its corrosion resistance rose significantly.Namely,the endurance of the cerium conversion coating against neutral salt spray increased from 10 h to 72 h after sealing treatment.

关 键 词：封闭处理 氟硅酸盐 氟钛酸铵 铈盐转化膜 镀锌钢 

分 类 号：TG174.4[金属学及工艺—金属表面处理]