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Hot Corrosion Resistance of Nickel Based Alloys Evaluated by a Molecular Orbital Calculation.

通过分子轨道计算评估镍基合金的热腐蚀性能。

基本信息

批准号：
08650815
负责人：
MURATA Yoshinori
金额：
$ 1.54万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650815/
关键词：
nickel alloys hot corrosion resistance molecular orbital calculation 高温耐食性

项目摘要

The purposes of this project are to obtain electronic parameters for evaluating the hot corrosion resistance of nickel based alloys and to make clear the role of alloying transition elements in hot corrosion resistance of the alloys. For these purposes, DV-Xalpha cluster method, which is a molecular orbital calculation, was employed using two kinds of hypothetical atom clusters. They are an MNi_<13>Na_2Cl_2 cluster and an MNi_<12>SO_4 cluster, which were used for evaluating the alloying effect on the hot corrosion resistance to Cl and to SO_4, respectively. The alloying elements for the calculation are 3d, 4d and 5d transition elements. Also a series of experimental work on hot corrosion tests was carried out using nickel binary alloys containing various 3d transition metals. The results obtained from the calculation and the experiment are summarized as follows ;(1) On the basis of the bond order ratio Bo (M-Cl) /Bo (M-Ni) which was calculated by the cluster method using the MNi_<13>Na_2Cl_2 cluster, Fe, Co and Cu were considered to be useful elements for increasing the hot corrosion resistance to chlorine. Here, Bo (M-Cl) is the covalent bond strength between M and Cl atoms, and Bo (M-Ni) is the covalent bond strength between M and Ni atoms. The results obtained from the calculation were consistent with the experimental results using molten NaCl salt in argon atmosphere.(2) On the basis of the calculation using the MNil_2SO_4 cluster, it was suggested that the degree of the bond strength between oxygen and sulfur affected the stability of nickel oxides containing the alloying element, resulting in changing the corrosion resistance. In this point view, it was suggested that both Mo and Re should improve the hot corrosion resistance to sulfur.(3) The magnitude of oxygen potential affected significantly the experimental results using molten NaCl salt.

本课题旨在获得评价镍基合金耐热腐蚀性能的电子参数，明确合金过渡元素在合金耐热腐蚀性能中的作用。为此，采用分子轨道计算的dv - x - α簇法，采用两种假设的原子簇。它们分别是MNi_<13>Na_2Cl_2团簇和MNi_<12>SO_4团簇，分别用于评价合金对耐Cl和SO_4热腐蚀性能的影响。计算的合金元素为3d、4d和5d过渡元素。并对含多种三维过渡金属的镍二元合金进行了热腐蚀试验。计算和实验结果总结如下：(1)根据MNi_<13>Na_2Cl_2簇簇法计算的Bo (M-Cl) /Bo （M-Ni）键序比，认为Fe、Co和Cu是提高耐氯热腐蚀性能的有用元素。其中，Bo （M-Cl）为M与Cl原子之间的共价键强度，Bo （M-Ni）为M与Ni原子之间的共价键强度。计算结果与氩气中NaCl熔盐的实验结果一致。(2)基于mil_2so_4簇的计算，认为氧硫结合强度的大小影响了含合金元素的氧化镍的稳定性，从而改变了其耐蚀性。从这个角度来看，建议Mo和Re都应该提高对硫的热腐蚀性能。(3)氧势的大小对NaCl熔盐实验结果有显著影响。