硫酸羟胺作为促进剂时磷化的成膜机理及所得膜层的性能  

Formation mechanism and properties of phosphating film when using hydroxylamine sulfate as accelerant

作　　者：张巧云[1] 陈泽民[1] 张天金 ZHANG Qiao-yun;CHEN Ze-min;ZHANG Tian-jin(Faculty of Chemistry and Material Science, Langfang Teachers College, Langfang 065000,China)

机构地区：[1]廊坊师范学院化学与材料科学学院,廊坊河北065000

出　　处：《电镀与涂饰》2018年第23期1075-1079,共5页Electroplating & Finishing

基　　金：河北省教育厅重点项目(ZD2016104)

摘　　要：在由ZnO 80 g/L、H_3PO_4 312 g/L、HNO_3 60 g/L、Ni(NO_3)_2·6H_2O 1.2 g/L、Ca(NO_3)_2·4H_2O 0.14 g/L、Cu(NO_3)_2·3H_2O 0.01 g/L和MnH_2PO_4·4H_2O 0.028 g/L组成的磷化液中加入硫酸羟胺作为促进剂,通过电位-时间曲线测量、扫描电镜(SEM)、X射线光电子能谱(XPS)、X射线衍射(XRD)等手段分析了硫酸羟胺质量浓度对20钢在室温下磷化成膜过程的影响。成膜过程可以分为4个阶段:(1)电位正移,硫酸羟胺在基体表面吸附,尚无晶粒生成;(2)电位负移,阳极溶解,基体表面出现少量晶粒;(3)电位正移,基体表面以成膜反应为主;(4)电位趋于平稳,基体表面已完全被磷化膜覆盖,反应达到动态平衡。硫酸羟胺质量浓度为6.0 g/L时所得的磷化膜由Zn_2Fe(PO_4)_2·4H_2O和Zn_3(PO_4)_2·4H_2O组成,其耐蚀性比以1.0 g/L NaNO_2作为促进剂时所得磷化膜更佳。Hydroxylamine sulfate was added as accelerant to a phosphating solution comprising ZnO80g/L,H3PO4312g/L,HNO360g/L,Ni(NO3)2·6H2O1.2g/L,Ca(NO3)2·4H2O0.14g/L,Cu(NO3)2·3H2O0.01g/L,and MnH2PO4·4H2O0.028g/L.The effect of mass concentration of hydroxylamine sulfate on formation of phosphating film on20steel at room temperature was studied by potential vs.time curve measurement,scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),and X-ray diffractometry(XRD).The film forming process can be divided into four stages:(1)the potential shifts positively,and hydroxylamine sulfate adsorbs to the surface of substrate,but no grain forms;(2)the potential shifts negatively,the anode is dissolved,and a small amount of grains form on the substrate surface;(3)the potential shifts positively again,the formation of phosphate film is dominant on the surface of substrate;and(4)the potential tends to be constant,the substrate surface is entirely covered by a phosphate film,and the system is in dynamic equilibrium.The phosphating film obtained with6.0g/L of hydroxylamine sulfate was composed of Zn2Fe(PO4)2·4H2O and Zn3(PO4)2·4H2O,and had a better corrosion resistance than that obtained with1.0g/L NaNO2as accelerant.

关 键 词：常温磷化 促进剂 硫酸羟胺 亚硝酸钠 成膜机理 化学吸附 耐蚀性 

分 类 号：TG178[金属学及工艺—金属表面处理]