暂态线性极化技术研究Galfan与Galvalume的耐蚀性能

Study on the Corrosion-resistance of Zinc, Galfan and Galvalume Coating with Transient Linear Galvanostatic Polarization Method

利用暂态线性极化技术测定了Zn镀层以及Galfan、Galvalume镀层在不同腐蚀介质中、不同pH下的极化电阻R_p值,以及R_p随时间的变化规律。结果表明,腐蚀刚开始时,在pH=5和pH=7的1mol/L NaCl、0.5mol/LNa_2SO_4、0.5mol/L NaCl+0.25 mol/L Na_2SO_4腐蚀介质中,Galfan的R_p均约为Zn镀层的2倍,Galvalume的R_p均约为Zn镀层的3倍。腐蚀一定时间后,Zn镀层和Galfan的R_p均逐渐降低,而Galvalume的R_p除在1mol/L NaCl腐蚀介质中外皆不断升高。表明Galvalume的腐蚀产物对镀层有保护作用,使其耐蚀性进一步提高。

The polarization resistances ( Rp ) of zinc, Galfan and Galvalume coating in NaCl, Na2SO4 and NaCl + Na2SO4 solution was determined with transient linear galvanostatic polarization method. At the beginning of the corrosion test, the Rp of Galvalume and Galfan was about three and two times to zinc coating. With the corrosion going on, the Rp of zinc and Galfan was continuously reducing, but the Galvalume's Rp was rising except in NaCl solution. The results show that corrosion product of Galvalume can protect the coating, but the zinc and Galfan's can not.