Electrodeposition of Pd provides excellent chemical and low-contact resistance with good electrical properties, such as different types of electrical contacts in the electronics industry. The conventional Pd plating process utilizes ammonia-based electrolytes. Ammonia was added continuously to maintain the optimum pH range in Pd electrolyte. In addition, the harmful and strong odor of the evaporating ammonia necessitates the use of a ventilator. A further disadvantage is that the brass substrate is corroded by ammonia vapor, and the corrosion products can contaminate the electrolytes, thereby changing the technological properties of the deposited plating for the worse. Ethylenediamine has been proposed as an alternative to ammonia; however, Pd electrodeposition occurs as microcracks via hydrogen evolution. In this study, the effects of Pd electrolyte on ethylenediamine as a complexing agent and the properties of various additives are investigated to improve current density and internal stress in Pd electrodeposition that occurs on a brass substrate. Therefore, complexing agents such as 3-pyridine sulfonic acid, sodium nicotinate, butyne 1–4 diol, and sodium allylsulfonate are selected as additives, to serve as an alternative to ammonia in Pd electrolyte. In this study, the properties of electrodeposited Pd with various additives were examined. The effect of additives on Pd electrolytes can be classified as dense surfaces without defects such as microcracks and pinholes, which improved surface roughness and corrosion resistance. Particularly, Pd electrolyte using sodium nicotinate has relatively improved surface roughness and properties. Pd electrolyte was optimized under ammonia-free conditions by the addition of sodium nicotinate.

中文翻译：

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含添加剂的无氨电解液中钯电沉积的表征

Pd 的电沉积提供了优异的化学和低接触电阻以及良好的电气性能，例如电子工业中不同类型的电接触。传统的 Pd 电镀工艺使用基于氨的电解液。不断添加氨以保持 Pd 电解液中的最佳 pH 值范围。此外，蒸发的氨气的有害和强烈的气味需要使用呼吸机。另一个缺点是黄铜基材被氨蒸气腐蚀，腐蚀产物会污染电解液，从而使沉积镀层的工艺性能变差。乙二胺已被提议作为氨的替代品；然而，Pd 电沉积通过析氢以微裂纹的形式发生。在这项研究中，研究了钯电解液对作为络合剂的乙二胺的影响以及各种添加剂的性质，以提高黄铜基材上钯电沉积的电流密度和内应力。因此，选择络合剂如 3-吡啶磺酸、烟酸钠、丁炔 1-4 二醇和烯丙基磺酸钠作为添加剂，作为 Pd 电解液中氨的替代品。在这项研究中，研究了具有各种添加剂的电沉积 Pd 的特性。添加剂对Pd电解质的影响可归类为致密表面，无微裂纹和针孔等缺陷，提高了表面粗糙度和耐腐蚀性。特别是，使用烟酸钠的 Pd 电解质具有相对改善的表面粗糙度和性能。