含有复合缓冲剂碱性化学镀液对Ni-Fe-P合金镀性能的影响

Influences of Alkaline Electroless Plating Solution with Compound Buffering Agents on the Performances of Electroless Ni-Fe-P Ternary Alloy Coating

目前,Ni-Fe-P合金化学镀还存在许多缺点,基于硼酸和硫酸铵组成的复合缓冲剂,以硫酸亚铁为镀铁源,系统研究了配位剂、还原剂、缓冲剂、镍盐、硫酸亚铁浓度对化学镀Ni-Fe-P效果的影响;探明了镀速,镀层中Ni,Fe和P的含量,镀层硬度及其耐蚀性能随镀液组分的变化规律。结果表明:本法可以成功实现Fe,P含量可控、高速制备Ni-Fe-P合金镀层,镀液中的复合缓冲剂具有显著的加速剂功能,有利于加快镀速和提高镀层中的Fe,P的含量,有利于提高镀层的硬度;适量提高镍盐、硫酸铵和硼酸浓度,有利于加快镀速,适量提高硫酸亚铁和硫酸铵浓度,有利于提高镀层中的Fe含量,适量降低柠檬酸钠、硫酸铵或适量提高次磷酸钠浓度,可以提高镀层中的P含量,提高硼酸和硫酸铵浓度,可以提高镀层的硬度。

In basis of the compound buffering agents composed of boric acid and ammonia sulfate,employing ferrous sulfate as Fe source,the effects of concentrations of complexing agent( sodium citrate), reducing agent( sodium hypophosphite), buffering agents,nickel salt and ferrous salt on electroless Ni-Fe-P ternary alloy coating were studied systematically. Subsequently,variation laws of plating rate,contents of elements( Ni,Fe and P),coating hardness and corrosion resistance as the change of plating solution constituent were investigated. Results showed that by this method,the Ni-Fe-P alloy coating could be prepared rapidly with controllable contents of Fe and P elements. Moreover,the compound buffering agents in plating solutions with significant accelerator features was beneficial to accelerating plating rate,increasing the contents of Fe and P elements,and improving coating hardness. Moreover, improving suitably the concentrations of nickel salt,ammonium sulfate and boracic acid could accelerate the plating rate. With the proper increases of ferrous sulfate and ammonium sulfate concentrations,the content of Fe in coating could enhance,while reducing the concentrations of citric acid sodium and ammonium sulfate or improving the concentration of sodium hypophosphite could enhance the content of P in coating.Besides,improving the concentration of boric acid and ammonium sulfate could enhance the coating hardness.