Process of pulse electrodeposition nanocrystalline chromium from trivalent chromium bath
Nanocrystalline chromium coating was prepared by pulse electrodeposition from trivalent chromium bath containing carboxylate-urea as complexing agent.The effects of electrodeposition parameters such as current density,bath temperature and solution concentration on the thickness and electrodeposition velocity of Cr deposited films were investigated.The crystallographic structures,morphology and chemical composition of Cr deposited films were analyzed by means of XRD,SEM and EDS.The results indicate that the deposited films with thickness up to 11.2 μm possess a smooth and clean appearance,and the grain size is less than 100 nm.The coating is pure chromium and the Cr deposit has face-centered cubic (fcc) structure and exhibits a (210) growth preference.Both the electrodeposition velocity and thickness exist maximum under different concentration complex agents,ureas,acetates,different temperatures and current densities.Compared with direct current electrodeposition,the thicker coating and finer grains can be obtained at lower temperature and current density by pulse electrodeposition.The electrodepostion velocity is about 0.24 μm/min,which is faster than that by direct current electrodeposition.In 1 mol/L H2SO4,3.5％ NaCl and 10％ NaOH solution,corrosion potential of Cr pulse-deposited film is about 100 mV higher than that of direct current.Corrosion and passivation current densities are lower and the nanocrystalline exhibits better corrosion resistance.
pulse electrodeposition trivalent chromium chromium coating nanocrystalline
HE Xin-kuai QIU Guan-zhou CHEN Bai-zhen ZHOU Ning-bo WU Lu-ye XU Li-jian
School of Resources Processing and Bioengineering,Central South University,Changsha 410083,China;Sch School of Resources Processing and Bioengineering,Central South University,Changsha 410083,China School of Packaging and Printing,Hunan University of Technology,Zhuzhou 412008,China
国际会议
2007年国际有色金属大会(International Conference of Nonfereous Materials 2007)(ICNFM)
长沙
英文
2007-11-28（万方平台首次上网日期，不代表论文的发表时间）