材料期刊网

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20 μm/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,Nr-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,氯基硫脲的性能优于巯基琥珀酸.

Electroless nickel plating process is the controlledautocatalytic reduction of nickel ions using suitable reducingagent such as sodium hypophosphite on certain catalyticsurfaces, which results in the production of well-adherentcoatings for a number of applications. Usually the rate ofelectroless deposition of nickel with hypophosphite asreducing agent is below 20 microns per hour. Hence theelectroless deposition of nickel in hypophosphite solutionwas investigated in the presence of thiourea or its derivativesas accelerator at a small concentration. The performances ofvarious accelerating agents during the plating process wereevaluated by potentiodynamic polarization (both anodic andcathodic) and cyclic voltammetric studies. The resultsshowed that all the sulfur compounds studied have anobvious anodic depolarizing effect. The performances of theaccelerators are in the following descending order:methylthiourea > N,N'-ethylene thiourea > allylthiourea >acetylthiourea > p-tolylthiourea > thiourea > diphenyl-thiourea; and thiosemicarbazide > thiomalic acid.