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将5,5-二甲基乙内酰脲(DMH)加入丁二酰亚胺镀银溶液中,考察了DMH的添加量对镀银层外观、光泽度、镀液阴极电流密度上限及沉积速度的影响,采用扫描电镜观察镀层的微观形貌。结果表明,当DMH质量浓度为20 g/L时,可获得结合力、抗变色能力良好,光泽度为232 Gs的镀银层,Jκ上限为0.76 A/dm2,沉积速率为1.263 g/(dm2·h)。 相似文献
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介绍了适用于输配电铜及铜合金件镀银工艺,其流程主要包括化学除油、盐酸活化、混酸酸洗、氰化镀铜、氰化镀银、电解钝化.说明了各工艺的操作条件及注意事项.给出了银镀层变色后的处理,不合格品的褪镀方法,以及镀层抗变色性能、结合力和显微硬度的测试方法.指出了该工艺对环保方面的要求.针对实际生产中遇到的漏镀和镀层有少量颗粒的问题,... 相似文献
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以电流效率、电流密度及镀层性能为评价指标,分别研究了焦磷酸钾、酒石酸钾钠、三乙醇胺、柠檬酸对丁二酰亚胺体系无氰电镀Cu-Zn合金镀层的影响。镀液配方及工艺条件为:CuSO_4·5H_2O 40 g/L,ZnSO_4·7H_2O 16 g/L,丁二酰亚胺90 g/L,辅助络合剂适量,硝酸钾20 g/L,pH值9.0,温度25℃,时间5 min。四种辅助配位剂中,酒石酸钾钠对镀层光泽度、电流效率及电流密度上限的影响最显著。另外,酒石酸钾钠或焦磷酸钾作辅助配位剂时,电流密度下限明显降低。 相似文献
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本文采用循环伏安法(CV)和计时电流法(CA)考察了在有无丁二酰亚胺添加的条件下低共熔溶剂(DESs)中银的结晶成核机理;利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)观察镀液浓度变化对镀层微观形貌以及相组成的影响。计时电流的结果表明,丁二酰亚胺的加入使Ag的结晶方式发生改变,Ag在DESs-0.6 mol/L丁二酰亚胺和0.1 mol/L AgNO3中电结晶过程是受扩散控制的三维连续成核。随着丁二酰亚胺的加入,镀层表面Ag结晶更加细致,结晶度增大,并且银镀层耐腐蚀性能得到提高。 相似文献
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脉冲无氰镀银及镀层抗变色性能的研究 总被引:2,自引:0,他引:2
采用赫尔槽试验筛选出一种阴离子表面活性剂及含氮杂环化合物作为脉;中无氰镀银的添加剂,并初步确定了无氰镀银的工艺条件及脉冲条件一通过正交试验进一步化化脉冲条件及镀银添加剂含量分别为:脉宽1ms、占空比10%、平均电流密度0.6A/dm^2、阴离子表面活性剂及含氮杂环化合物含量分别为12mg/L、110mg/L测定了该镀银层的耐蚀性、抗变色性能及与基体的结合力,并用扫描电镜对其微观形貌进行了观察。结果表明,脉冲无氰镀银层的抗变色性能优于直流无氰镀银层;光亮镍打底后再脉冲无氰镀银,可获得更加光亮、结晶细致的镀银层,且抗变色性能及耐蚀性均增强. 相似文献
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以镀层表面形貌和显微硬度为考核指标,采用正交试验法优选了脉冲镀银参数,采用优选的脉冲参数电镀与直流电镀的银镀层作了比较。研究结果表明,脉冲电镀所得镀银层结晶细致,孔隙率低,镀层结合力、显微硬度及耐磨性均明显优于直流镀银层。 相似文献
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Zinc-manganese alloys were electrodeposited using pulse techniques: pulse, pulse reverse and superimposed pulse. The alloys obtained under each condition were characterized by their composition, thickness, morphology and structure. Results indicate that, in the same interval of average current densities, all methods led to similar or higher manganese contents than those obtained using direct current (dc), but current efficiencies were lower. In general, all pulse methods improved the thickness and composition uniformity of the alloys, particularly, when pulse reverse plating was used. However, current efficiencies with this method were so low that the process would be uneconomical. With pulse and superimposed pulse techniques uniform and compact alloys were obtained, the latter method with current efficiencies that were slightly higher than the former. Moreover, the structure of the alloys obtained with the pulse techniques was simpler than that observed with dc plating and monophasic alloys could be obtained in a wide interval of conditions. 相似文献