分散剂对电沉积Ag/C复合层腐蚀性能的影响

Effect of Dispersant on Corrosion Behavior of Electrodepo-sited Silver/Carbon Composite Coating

为了更系统地研究分散剂对无氰电沉积Ag/C复合层耐蚀性的影响,在以KI为配位剂的无氰电沉积Ag/C镀液中加入石墨粉和自制含羧基分散剂,在铜片表面电镀Ag/C复合层。利用扫描电镜和能谱仪分析了Ag/C复合镀层的表面形貌及成分;通过抗硫化变色性能试验、Tafel极化曲线等研究了分散剂用量对复合镀层在SO2,H2S气体及Na2S,K2SO4溶液中腐蚀特性的影响。结果表明:分散剂最佳用量为5 m L/L,此时石墨在镀液及镀层中分散效果最好,所得镀层也最均匀、细致;镀液中含分散剂时所得Ag/C复合层在H2S,SO2气氛中及Na2S和K2SO4溶液中的抗硫化变色能力均较强。

Graphite powder and hydroxyl-containing dispersant were introduced into the cyanide-free Ag / C electroplating bath containing KI as the complexing agent. Resultant electroplating bath was adopted to prepare Ag / C composite electroplating coating on Cu plate. The surface morphology and composition of the as-prepared Ag / C coating were analyzed by scanning electron microscopy and energy dispersive spectrometry. Moreover,the effect of the dispersant dosage on the corrosion behavior of the as-prepared Ag / C composite coating in SO2 and H2S gases as well as Na2 S and K2SO4 solutions was evaluated based on anti-sulfurization-tarnishing test as well as polarization curve measurement. Results indicated that when the dosage of the dispersant was fixed as 5 m L / L,the graphite powder exhibited the best dispersibility in both the electroplating bath and electroplated Ag / C composite coating,and the Ag / C composite coating prepared at this dispersant dosage was of the best uniformity and compactness. Besides,the Ag / C composite coatings obtained from the electroplating bath containing the dispersant exhibited good corrosion resistance in SO2 and H2S gases as well as Na2 S and K2SO4 solutions.