北方地区雪水对Q235钢腐蚀性的电化学研究

Electrochemical Study of Q235 Steel in the Snow Water in North Region

采用浸泡、动电位极化和交流阻抗等方法研究了Q235钢在北方地区雪水中的腐蚀行为,考察了Ni-Fe-P化学镀层对Q235钢在雪水中腐蚀的防护效果。结果表明:Q235钢在雪水、自来水和质量分数3.5%NaCl溶液中均表现为均匀腐蚀,但由于雪水中含有的氟化物、氯气、二氧化硫等物质溶解后产生了F-、Cl-和SO24-等离子,增加了雪水的导电性,使雪水的腐蚀速率高于自来水。同时,由于离子浓度相对较低,腐蚀性又低于NaCl溶液。温度升高会加速Q235钢在雪水中的腐蚀。交流阻抗结果表明:Ni-Fe-P化学镀层比Q235钢在雪水中具有更大的电荷转移电阻,表明该镀层具有更低的腐蚀速率,可以作为Q235钢在雪水或严重污染的潮湿空气中的防护措施。

The corrosion behavior of Q235 steel in the snow water, collected from North region, was studied by immersion, polarization curves and EIS, and the corrosion protection effect of Ni--Fe--P coating was tested. The results show that Q235 steel exhibits a general corrosion in the snow water, and the corrosion rate of Q235 steel in snow water is higher than that in tap water, because the conductivity of snow waster contained F , Cl- and SO42- is bigger than that of tap water. Meantime, the corrosion is lower than that of 3.5 % NaCl solution because of the lower ion concentration for the snow water. In addition, the corrosion rate of Q235 steel in snow water was increased with increasing temperature. The EIS display that the charged transfer resistance of Ni--Fe--P electroless coating in snow water is bigger than that of Q235 steel, which means the corrosion rate is lower, and the coating can be one of methods used corrosion protection for Q235 steel in snow water or wet and serious polluted air.