热镀锌层在模拟湿热酸性大气环境中的耐蚀性研究

目的研究Q420钢表面热镀锌工艺中,Zn和Zn-Al-Ni-RE合金镀层在酸性铜离子加速盐雾试验条件下的耐蚀性能。方法 Q420钢表面预处理后进行热镀锌,根据GB 6460—1986进行铜加速醋酸盐雾腐蚀试验,对比纯Zn镀层与Zn-Al-Ni-RE合金镀层的耐蚀性。结果 Ni,RE等元素的加入使镀层表面光亮,组织更加细密。在酸性铜离子加速实验进行到192 h时,纯锌镀层的腐蚀质量损失是合金镀层的2.7倍;72 h后纯锌镀层出现红锈,120 h后合金镀层出现红锈,说明Zn-Al-Ni-RE合金镀层比纯Zn镀层更耐腐蚀。结论通过适量添加Al,Ni与稀土元素,能使Q420钢合金镀层的耐蚀性能大幅度提高。

Research on the Corrosion Resistance of Hot Dip Galvanized Coating in Simulated Hot and Humid Acidic Atmospheric Environment

Objective To study the corrosion resistance of hot dip galvanized pure Zn and Zn-Al-Ni-RE alloy coatings of high-strength steel Q420 under the acidic and copper accelerated salt spray corrosion condition. Methods On the basis of surface pre-treatment, the Q420 steel was treated by hot dip galvanizing. Copper accelerated acetic acid salt spray corrosion test was carried out according to GB 6460—1986, and the corrosion resistance of the pure Zn coating and Zn-Al-Ni-RE coating was compared. Results With the addition of Ni, RE and other elements, the coating surface was bright and the microstructure became finer. After 192 h, the corrosion weight loss of pure zinc coating was 2. 7 times higher than the corrosion weight loss of Zn-Al-Ni-RE alloy coatings un-der the acidic and copper accelerated salt spray corrosion condition. Pure zinc coating showed red rust after 72 h, while Zn-Al-Ni-RE alloy coating showed red rust after 120 h, so Zn-Al-Ni-RE alloy coating was more corrosion resistant than the pure Zn coating. Conclusion By means of adding nickel aluminum elements and rare earth elements, the corrosion resistance of alloy coating was greatly improved.