磷酸锌对环氧涂层破损处金属的缓蚀作用

用电化学阻抗谱（EIS）、电化学噪声（EN）及扫描电化学显微镜（SECM）等方法对带有划痕的环氧清漆涂层和环氧/磷酸锌涂层进行了测试，研究了磷酸锌对涂层破损处金属的缓蚀作用。EIS和EN的结果表明：加入磷酸锌后涂层下金属基体的腐蚀受到抑制；SECM结果直观地证明了磷酸锌对涂层划痕有修复作用。用电化学噪声的散粒噪声理论并结合随机分析方法研究了磷酸锌的作用机制，结果发现加入磷酸锌不但大大减缓了腐蚀的孕育速度，还降低了腐蚀的生长概率，因而能够减缓金属基体腐蚀的进行。

ROLES OF ZINC PHOSPHATE ON THE CORROSION OF THE SCRATCHED EPOXY COATING

The roles of zinc phosphate on the corrosion of the scratched coating were studied by electrochemical impedance spectroscopy(EIS), electrochemical noise measurements(EN) and scanning electrochemical microscopy(SECM). The experimental results of EN and EIS revealed that zinc phosphate had inhibition effect on the corrosion of the scratched epoxy coatings. The SECM results implied that the scratched surface of zinc phosphate coating was healed by an insulated film indeed. The mechanism of zinc phosphate on the corrosion of the scratched coating was analyzed based on the combined stochastic theory and shot noise theory using the Weibull distribution and Gumbel distribution function. It showed that the corrosion generation rate and the corrosion growth probability of the metal under the coatings were decreased with the addition of zinc phosphate.