Cr对Fe-Cr合金耐蚀性能影响的电子理论研究

发布时间：2018-02-24 17:14

本文关键词： 经验电子理论耐腐蚀性能钝化膜界面电子密度差 Tammann定律　出处：《金属学报》2017年05期 　论文类型：期刊论文

【摘要】：基于固体与分子经验电子理论(EET),对Fe-Cr合金(Cr含量为0~30%,原子分数)的价电子结构进行了半定量分析,利用界面电子密度差Dr的计算方法,计算了Fe-Cr合金与Cr_2O_3、Fe_2O_3钝化膜低指数晶面间的电子密度。结果表明,Fe-Cr合金固溶体的杂化原子轨道数sn、最强键共价电子数nA和最强键键能EA均大于纯Fe,Cr能提高Fe基体的稳定性。当Cr含量达到12.52%和24.3%时,Cr原子从低阶迁移到共价电子数少的高阶状态,不稳定性增加,此时Cr易偏离平衡位置与腐蚀介质作用形成钝化膜,造成Fe-12.52%Cr和Fe-24.3%Cr合金的耐腐蚀性能发生突变。Fe-Cr合金与Cr_2O_3、Fe_2O_3钝化膜的24个低指数界面中,只有Fe-Cr(112)/Cr_2O_3(0001)、Fe-Cr(112)/Cr_2O_3(1010)_(Cr)、Fe-Cr(112)/Fe_2O_3(11 20)界面的Dr10%,对于同等Cr含量的基体,Fe-Cr(112)/Cr_2O_3(1010)_(Cr)界面Dr最小,满足Dr10%的杂化原子轨道数s最大。随着基体中Cr含量升高,Fe-Cr(112)/Cr_2O_3(0001)和Fe-Cr(112)/Fe_2O_3(11 2ˉ0)界面Dr降低,s增加,Cr_2O_3、Fe_2O_3与基体的界面更加稳定牢固,因此Fe-24.3%Cr合金的耐腐蚀性可跃迁至更高水平。价电子结构对Fe-Cr合金耐蚀性能变化的分析结果基本符合Tammann定律的描述。
[Abstract]:Based on the empirical electron theory of solid and molecule, the valence electron structure of Fe-Cr alloy with Cr content of 0 ~ 30 and atomic fraction is semi-quantitatively analyzed, and the calculation method of interfacial electron density difference (Dr) is used. The electron density between Fe-Cr alloy and Cr _ 2O _ 3 / Fe _ 2O _ 3 passivating film is calculated. The results show that the atomic orbital number of hybrid atom in solid solution of Fe-Cr alloy is snn, the strongest covalent electron number na and the strongest bond energy EA are higher than that of pure Fe _ 2O _ 3 alloy. Stability. When Cr contents reach 12.52% and 24.3, Cr atoms migrate from lower order to higher order with less covalent electrons. When the instability increased, Cr easily deviated from the equilibrium position to form a passivation film, which resulted in sudden changes in the corrosion resistance of Fe-12.52%Cr and Fe-24.3%Cr alloys. Fe-Cr alloy and Cr _ 2O _ 3- Fe _ 2O _ 3 passivated film in the 24 low-index interfaces of the passivating film. Only Fe-Cr-112Cr2O30001 / Fe-Cr2O30001 / Cr2O3 / Cr2O3 / Cr2O3101010 / C / Cr / Cr / 112C / Cr2O3 / C / Cr2O2C / Cr2O30001 / C / Cr / 112C / Fe2O311.20) interface is the lowest in the case of Fe-Cr112Cr2O31010 / C / C) interface, and the interface between Fe-Cr2O3Fe2O3Cr2O3 and Cr2O3Fe2O3 / Cr2O3Fe2O3 / Cr2O3Cr2O3 / Cr2O3Cr2O3 / Cr2O3Cr2O3 / Cr2O3Cr2O3 / Cr2O3Cr2O3 / Cr2O3Cr2O3 / Cr2O3Cr2O3 is more stable and stable with the increase of Cr content in the matrix as the content of Cr in the matrix increases, and the Fe-Cr2O30001Cr2O30001 and Fe-Cr(112)/Fe_2O_3(11 2o) interfaces decrease and increase the stability of the interface between Cr2O3Fe2O3 and Cr2O3Fe2O3. Therefore, the corrosion resistance of Fe-24.3%Cr alloy can be shifted to a higher level, and the analysis results of valence electron structure for the change of corrosion resistance of Fe-Cr alloy are basically in accordance with the description of Tammann's law.
【作者单位】：西南石油大学材料科学与工程学院;西南石油大学油气藏地质及开发工程国家重点实验室;
【基金】：国家高技术研究发展计划项目No.2006AA06A105 西南石油大学油气藏地质及开发工程国家重点实验室基金项目No.PLN0609~~
【分类号】：TG174.4

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