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为了改善Q235钢在空气污染较为严重的环境中的耐蚀性,以北方重工业城市之一的抚顺望花区的雪水为腐蚀溶液,考察了化学镀镍层在该介质中的耐蚀行为。采用金相显微镜观察了镍磷镀层的表面形貌,通过冷冻-加热循环试验考察了镀层的结合力,借助动电位极化、电化学阻抗谱等方法评价了镀层在雪水中的耐蚀性,测试和观察了浸泡实验的腐蚀速率和表面形貌。结果表明,Ni-P镀层可在Q235钢表面均匀沉积且较为致密,与基体之间有良好的结合力。镀层的自腐蚀电流密度较Q235钢低,电荷转移电阻更大,腐蚀速率是Q235钢的1/3～1/2。Ni-P镀层明显改善了Q235钢在污染较为严重的雪水中的耐蚀性,可作为Q235钢腐蚀防护的一种措施。
In order to improve the corrosion resistance of Q235 steel in the environment with severe air pollution, the corrosion resistance of Q235 steel in the medium of Fushun Wanghua, a heavy industrial city in northern China, was investigated. The surface morphology of the Ni-P coating was observed by optical microscope. The adhesion of the Ni-P coating was investigated by freeze-drying cycle. The corrosion resistance of the coating in snow water was evaluated by means of potentiodynamic polarization and electrochemical impedance spectroscopy. The corrosion rate and surface topography of the immersion test were tested and observed. The results show that the Ni-P coating can be uniformly deposited on the surface of Q235 steel and more dense, with good adhesion between the substrate. The self-corrosion current density of the coating is lower than that of Q235 steel, and the charge transfer resistance is larger. The corrosion rate is 1/3 to 1/2 of Q235 steel. Ni-P coating significantly improves the corrosion resistance of Q235 steel in the more polluted snow water, which can be used as a measure to prevent corrosion of Q235 steel.