Co-Fe-B非晶态合金成键及电子性质的DFT研究

利用密度泛函理论(DFT),通过团簇Co2FeB2,CoFe2B2的优化和计算,研究Co-Fe-B非晶态合金成键及电子性质.结果表明:团簇Co2FeB2(富Co)中主要的电子流向为B→Co,B→Fe,而团簇CoFe2B2(富Fe)电子流向多样化,这导致富Co合金中键级比例分布不均匀,而富Fe合金中键级比例相对均匀;另外,金属与B原子成键对合金稳定性的贡献最大,而两种团簇的M(max)-B与Co-Fe键协同作用相反:富Co团簇中Co-B与Co-Fe成键强度同增同长,而富Fe团簇中Fe-B与Co-Fe成键强度相互抑制.以上结论在一定程度上解释了富Co合金热稳定性差的现象.另外,B原子使富Fe团簇空间结构、成键以及电子流动方向更加复杂,使合金非晶态化增加.Co-Fe-B非晶态合金中存在B原子之间近距离接触,希望此结论不久后得到实验验证.

DFT Stuty of Bonding and Electronic Property in Co-Fe-B Amorphous Alloy

Possible configurations of cluster Co2FeB2 and CoFe2B2 were Calculated and optimized with the Density Functional Theory(DFT)method,in order to study the Bonding and Electronic Property in Amorphous Co-Fe-B Alloy.The results showed that the flow of electronics is from atom B to atom Co and Fe in high Co Cluster Co2FeB2,ulike cluster Co2FeB2,the flow of electron in high Fe cluster CoFe2B2 is more complex.It makes a more uniform distribution of bonding among all atoms and various kinds of bonding were generated for the stability of cluster CoFe2B2;Further more,M-B bonding has biggest contribution to Amorphous Alloy and synergistic effects of M(max)-B and Co-Fe bonding are inverse in different Cluster:the variation trend of Co-B and Co-Fe Bonding strength have same tendency in Co-rich cluster Co2FeB2,in contrast,the tendency of FeB and Co-Fe is inverse in Fe-rich cluster CoFe2B2,those maybe the reason that the thermal stability is weak for Co-rich Alloy.In addition,atom B made the structure,bonding and flow of electron of low Co cluster more complex and made it easier to generate amorphous alloy.B-B close contact can be found in amorphous Co-Fe-B alloy system,we hope the conclusion could be verified by experimental result soon.