铝基化学镀镍磷合金层耐蚀性及其机理

Corrosion Resistance of Ni P Alloy Electroless Deposit on Aluminiumand Its Mechanism

用线性极化法和孔蚀实验评定了镀覆在铝材上的４种磷含量和磷分布不同的化学镀镍磷合金镀层在１０％Ｈ２ＳＯ４，１０％ＮａＯＨ，１０％ＨＣｌ和３．５％ＮａＣｌ溶液中的耐蚀性，观察的镀层包括高磷（ＨＰ）、低磷（ＬＰ）、以及含磷量从镀层底部到顶面为高到低（ＨＬ）和为低到高（ＬＨ）的４种镀层。结果发现，在Ｈ２ＳＯ４和ＮａＯＨ溶液中ＬＨ和ＨＬ镀层的耐蚀性最好，在ＨＣｌ溶液中ＬＨ和ＨＰ最佳，而ＬＰ镀层则在上述３种溶液中都是最差的。４种镀层的耐孔蚀性由高至低依次为ＬＨ、ＨＰ、ＨＬ和ＬＰ。文中还讨论了耐蚀性机理。

Ni-P alloy films with different phosphorus content and in different component distribution are electroless plated on aluminium surfaces to observe their corrosion resistance in the solutions of 10%H2SO4, 10%NaOH, 10%HC1and 3.5%NaC1 respectively through linear polarization and pitting corrosion experiments. The specimen films include the one in high phosphorus (P) content (HP), the one in low P content (LP), the one with its P content decreases from base to top surface(HL),and the one with its P content increases from base to top surface (LH) .It was found that from the point of corrosion resistance.LH and HL are the best two films in H2SO4 and NaOH solutions,whereas the LH and HP are the best two in HC1 solution,but LP is the worst in any of the three solutions. The specimen films showed their pitting corrosion resistance from high to low in the order of LH, HP, HL and LP. Mechanism of corrosion resistance is also discussed.