材料期刊网

利用脉冲电镀技术在Q235钢基体上制备了纳米孪晶镍镀层，分别测试了纳米孪晶镍镀层和铸态镍在pH8.4的硼酸缓冲溶液（0.1 mol/L H₃BO₃+ 0.025 mol/L Na₂B₄O₇）中的动电位极化曲线。结果表明，两者在硼酸缓冲溶液中均能自钝化，并且前者具有较好的耐腐蚀和钝化性能。利用Mott--Schottky 关系和点缺陷模型（PDM），分别从热力学和动力学两方面研究了纳米孪晶结构对钝化膜性能的影响，发现纳米孪晶结构对钝化膜中的缺陷密度影响较小，对缺陷在钝化膜中的扩散系数（D_m）却有着显著的影响，这是导致其上生长的钝化膜薄且致密、耐蚀性能好的主要原因。

A nickel coating with high density nano--scale twins has been synthesized on
Q235 steel by using pulsed electrodeposition technique. The potentiodynamic polarization measurements were performed on nano--scale twin nickel coating and cast nickel in 0.1mol/L H₃BO₃ + 0.025 mol/L Na₂B₄O₇ buffer solution with pH= 8.4. The results indicated that both samples showed auto--passivated behavior, while nano-scale twin nickel coating possessed higher corrosion resistance and better passive property than cast nickel. The effect of nano-scale twin structure on the properties of passive film was investigated in terms of thermodynamics and kinetics by using Mott-Schottky relationship and point defect model (PDM). It demonstrated that nano--scale twin structure has little effect on the defect density, but has great effect on the diffusion coefficient (D_m). It is the main cause to the formation of a thinner, more compact and higher corrosion resistant film on the nano-scale twin nickel coating.