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考察了甲醇汽油发动机缸套材料铸铁及其表面碳化钨涂层在甲酸水溶液中的腐蚀性能,并研究了其电化学腐蚀行为;采用电化学腐蚀中的极化曲线和电化学阻抗来表征其电化学腐蚀性能。结果表明:碳化钨涂层可有效地改善甲醇汽油发动机缸套材料铸铁的耐腐蚀性能;与铸铁相比,碳化钨涂层的自腐蚀电位高、自腐蚀电流小;同时碳化钨涂层使铸铁表面电荷的传输电阻变大,抑制了铸铁在甲酸溶液中的自放电功能,阻碍了电化学腐蚀的进行,从而有效地保护发动机缸套材料铸铁。
The corrosion behavior of cast iron with methanol gasoline engine liner and tungsten carbide coating on its surface in aqueous solution of formic acid was investigated and its electrochemical corrosion behavior was investigated. The polarization curve and electrochemical impedance in electrochemical corrosion were used to characterize the corrosion resistance Chemical corrosion performance. The results show that the tungsten carbide coating can effectively improve the corrosion resistance of cast iron cylinder liner material of methanol gasoline engine. Compared with cast iron, the self-corrosion potential of tungsten carbide coating is high and the self-corrosion current is small. At the same time, Surface charge transmission resistance becomes larger, inhibiting the self-discharge of cast iron in formic acid solution, impeding the electrochemical corrosion, so as to effectively protect the engine cylinder liner cast iron.