化学镀镍过程的动电位及循环伏安研究(英文)

Potentiodynamic polarization and cyclic voltammetric studies of electroless nickel plating process

化学镀镍是一个采用合适的还原剂(如次磷酸钠)使镍离子在某催化界面上可控地自催化还原的过程,所生成的膜层附着良好,应用广泛。以次磷酸盐作为还原剂时,化学镀镍的沉积速率通常低于20μm/h,故研究了在有少量硫脲或其衍生物作为加速剂的条件下,次磷酸盐体系中镍的化学沉积过程。通过动电位阴、阳极极化和循环伏安研究,评价了镀覆过程中各种加速剂的性能。结果表明,所研究的硫化物都有明显的阳极去极化作用。各种加速剂性能的优劣顺序为:甲基硫脲>N,N′–乙烯硫脲>烯丙基硫脲>乙酰硫脲>对甲苯基硫脲>硫脲>二苯基硫脲。此外,氨基硫脲的性能优于巯基琥珀酸。

Electroless nickel plating process is the controlled autocatalytic reduction of nickel ions using suitable reducing agent such as sodium hypophosphite on certain catalytic surfaces, which results in the production of well-adherent coatings for a number of applications. Usually the rate of electroless deposition of nickel with hypophosphite as reducing agent is below 20 microns per hour. Hence the electroless deposition of nickel in hypophosphite solution was investigated in the presence of thiourea or its derivatives as accelerator at a small concentration. The performances of various accelerating agents during the plating process were evaluated by potentiodynamic polarization （both anodic and cathodic） and cyclic voltammetric studies. The results showed that all the sulfur compounds studied have an obvious anodic depolarizing effect. The performances of the accelerators are in the following descending order： methylthiourea 〉 N,N＇-ethylene thiourea 〉 allylthiourea 〉 acetylthiourea 〉 p-tolylthiourea 〉 thiourea 〉 diphenylthiourea; and thiosemicarbazide 〉 thiomalic acid.