关键词: 无电镀镍复合镀层, 钻石微粒, PTFE, 耐蚀性

Abstract: The eletroless nickel composite coating was prepared by uniform dispersion of diamond (or PTFE) particles throughout electroless nickel deposition. Corrosion resistance of composite coating in 3.5% NaCl aqueous solution was investigated by electrochemical analysis, dipping test and salt spray test. The results showed that the corrosion resistance of composite coating was inferior to that of electroless nickel coating if small amount of particles was added to the composite coating. Microsturctural analysis by SEM,AES,XRD,and EPMA indicated that the distribution of phosphorus is not homogeneous in the composite coating. The phosphorus_rich region acts as microcathode, however, the phosphorus_lean region acts as microanode.The decrease in corrosion resisthnce may result from the presence of numerous microcells presented in the composite coating.Only when enough amount of particles is included in the composite coating,the protective effect due to inertness of particl is observed.