单相和双相不锈钢纳米涂层的电化学腐蚀行为

用磁控溅射技术在玻璃基体上制备由两种相组成(单相和双相)的不锈钢纳米涂层,利用动电位极化､交流阻抗技术及扫描电子显微镜研究两种不锈钢纳米涂层在0.25 mol/L Na2SO4 + 0.05 mol/L H2SO4 和 0.5 mol/L NaCl + 0.05 mol/L H2SO4溶液中的电化学腐蚀行为,观察相组成对纳米不锈钢涂层耐蚀性能的影响｡结果表明,与不锈钢单相涂层相比,不锈钢双相纳米涂层具有较差的抗局部腐蚀能力,其钝化膜的载流子密度远远大于不锈钢单相钝化膜的载流子密度,使得钝化膜的离子传输能力大大增强,从而降低了钝化膜的稳定性｡

ELECTROCHEMICAL CORROSION BEHAVIOR OF NANO-CRYSTALLINE STAINLESS STEEL COATING WITH DIFFERENT PHASE COMPOSITION

The single-phase (α) and duplex-phase (α+γ) nano-crystalline coatings have been fabricated on glass substrate by DC magnetron sputtering. The electrochemical corrosion behavior of the two NC coatings in solutions of 0.25M Na2SO4 + 0.05M H2SO4 and 0.5M NaCl + 0.05M H2SO4 was investigated by using potentiodynamic polarization, EIS and SEM. The results showed that there was a large difference in the corrosion behavior between the single-phase (α) and the duplex-phase (α+γ) nano-crystalline coatings. The duplex-phased coating is shown to have exhibited a lower localized corrosion resistance and possessed a less stable passive film than the single-phase coating. A similar two-layer semiconductor passive film was formed on both coatings; however, a great increase in carrier densities could be responsible for the low stability of the passive film on the duplex-phase coating.