气体氮化对碳钢耐蚀性的影响及化合物层的价电子理论分析  

Effect of Gas Nitriding on the Corrosion Resistance of Carbon Steel and Empirical Electron Theory Analysis of Compound Layer

作　　者：章敬保 杨川[1] 张程菘[1] 高国庆[1] 

机构地区：[1]西南交通大学材料科学与工程学院,成都610031

出　　处：《腐蚀与防护》2018年第3期207-212,共6页Corrosion & Protection

摘　　要：对Q235钢进行低温气体氮化。采用扫描电子显微镜(SEM),X射线衍射(XRD)和电化学试验研究了气体氮化对Q235钢耐蚀性的影响;并利用经验电子理论(EET)计算了表面层的价电子结构及共价键键能。结果表明:气体氮化增加了Q235钢的耐蚀性;经气体氮化处理后的试样表面最强键的键强nA和键能Ea都大大高于α-Fe结构单元的nA和Ea,表明价电子结构与腐蚀性能之间有着密切的相关性。由于N原子溶入到α-Fe中,导致主键络的nA、Ea增加,提高了表层结构的稳定性,这可能是提高氮化处理后试样耐蚀性的根本原因。Gas oxynitrocarburizing was carried out on Q235 carbon steel at low temperature, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and electrochemical methods were used to study the effect of oxynitrocarburizing on corrosion resistance of Q235 steel. And the empirical electron theory （EET） was applied to evaluate the structure of valence electrons and the energy of covalent bonds. The results showed that the corrosion resistance of Q235 carbon steel could be obviously improved by gas oxynitrocarburizing. The calculated results reveal that the largest bond strength nA and the bond energy Ea in the oxynitrocarburized layer were markedly higher than those in ccFe after gas oxynitrocarburizing, which indicates the close relationship between corrosion and structure of valence electrons. Meanwhile, the nA and Ea of main bonds increased due to the N atom dissolved in ccFe, which enhanced the phase stability of the oxynitrocarburized layer. This might be the primary mechanism for the excellent corrosion resistance of the oxynitrocarburized Q235 carbon steel.

关 键 词：气体氮化 Q235钢 耐蚀性 经验电子理论 

分 类 号：TG178[金属学及工艺—金属表面处理]