两种化学镀镍—钴—磷镀层的显微组织与耐蚀性

Microstructures and corrosion resistance of two kinds of electroless nickel-cobalt-phosphorus coatings

采用化学镀法在p型单晶硅片表面制备了2种镍-钴-磷合金镀层,对比研究了其显微组织和耐蚀性。结果表明,Ni48Co46P6镀层为非晶和纳米晶混合结构,表面均匀分布着粒径0.2～3.5μm的球状团簇;而Ni12Co84P4镀层为单相密排六方结构,平均晶粒尺寸约16nm,表面由长约1.0μm的梭状团簇组成。在10.0%NaOH溶液和3.5%NaCl溶液中,2种镀层的极化曲线均存在明显的钝化区域,且Ni48Co46P6镀层的耐蚀性较好;而在1.0%H2SO4溶液中,2种镀层的耐蚀性均大幅下降。

Two types of Ni-Co-P alloy coatings were prepared by electroless plating on p-type single crystal silicon wafers, and their microstructure and corrosion resistance were characterized and compared. The results indicated the existence of a mixture of amorphous and nanocrystalline structures for Ni48Co46P6 coating with nodules 0.2-3.5 μm in diameter distributing uniformly on the surface. The Ni12Co84P4 coating is characterized by a single hexagonal close-packed phase with an average grain size of 16 nm. The surface of Ni12Cos4P4 coating is composed of shuttle-shaped clusters with the length of ca.1.0μm. The polarization curves for both Ni48Co46P6 and Ni12Cos4P4 coatings in 10.0% NaOH and 3.5% NaC1 solutions exhibit apparent passivation regions, and the corrosion resistance of Nia8Coa6P6 coating is better than that of Ni12Co84P4 coating. However, the corrosion resistance of both coatings in 1.0% H2SO4 solution deteriorates greatly.