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在不同温度下对碳钢Q235和42CrMo钢进行气体渗氮,利用光学显微镜、扫描电镜、能谱仪及X射线衍射仪对比分析了Q235和42CrMo钢渗氮层的微观组织及相结构,并用电化学方法测试了样品的耐腐蚀性。经过渗氮处理后的样品的耐腐蚀性都较原材有大幅提高,而相同温度渗氮后42CrMo钢的自腐蚀电位较Q235钢的低,42CrMo钢渗氮层电阻小于Q235钢,碳钢渗氮层的耐蚀性优于合金钢。采用热力学和第一性原理计算探讨了42CrMo钢的合金元素对渗氮层的抗腐蚀性的影响。结果表明合金元素Cr、Mo通过降低Fe-N化合物稳定性从而降低渗氮层的抗腐蚀性。
Gas nitriding of carbon steel Q235 and 42CrMo steel was carried out at different temperatures. The microstructure and phase structure of nitrided layers of Q235 and 42CrMo steel were analyzed by optical microscope, scanning electron microscope, energy dispersive spectrometer and X-ray diffractometer. The electrochemical method tested the corrosion resistance of the sample. After nitriding the sample corrosion resistance than the original material has greatly increased, and the same temperature after nitriding 42CrMo steel corrosion potential of Q235 steel is lower, 42CrMo steel nitriding layer resistance is less than Q235 steel, carbon steel seepage Nitrogen layer corrosion resistance is better than alloy steel. The effects of alloying elements of 42CrMo steel on the corrosion resistance of nitrided layers were investigated by the thermodynamic and first principles calculations. The results show that the alloying elements Cr, Mo reduce the corrosion resistance of the nitrided layer by reducing the stability of the Fe-N compound.