化学镀镍-磷合金层表面化学镀金工艺及其性能

摘要

采用化学镀镍-磷/化学镀钯/置换镀金(ENEPIG)工艺获得镍/钯/金组合镀层,对比分析了它与化学镀镍/置换镀金(ENIG)、化学镀镍/化学镀金(ENEG)工艺的相关沉积特征及镀层耐蚀性能.镀金过程中开路电位和沉积速率均发生明显的变化,反映了基体电极表面状态的变化.ENEG工艺的化学镀金过程中的平台电位最正,沉积速率最快.与ENIG工艺的置换镀金相比,ENEPIG工艺中置换镀金的平台电位更正,对基体的腐蚀也更慢,所得置换镀金层更致密,具有良好的耐腐蚀性能.综合对比ENIG、ENEG、ENEPIG工艺所得3种镀层,ENEPIG工艺的镀层性能最优.%A nickel/palladium/gold composite coating was obtained by electroless nickel plating followed by electroless palladium plating and immersion gold plating (ENEPIG) successively.The related deposition properties of ENEPIG,ENIG (electroless nickel plating/immersion gold plating) and ENEG (electroless nickel/gold plating),as well as the corrosion resistance of their coatings were compared.Both open circuit potential and deposition rate during the gold plating change obviously,which reflects the change on the surface of substrate.The electroless gold plating in ENEG process has the highest potential platform and deposition rate.Compared with the immersion gold plating in ENIG process,the immersion gold plating in ENEPIG process has a higher potential platform and a lower corrosion rate of substrate.The obtained immersion gold coating is more compact and resistant to corrosion.It is found that the coating obtained by ENEPIG process has the best performances through a comprehensive comparison among the three kinds of coatings obtained by ENIG,ENEG and ENEPIG processes.