Fe2B相价电子结构及其本质脆性

根据固体与分子经济电子理论对Ｆｅ２Ｂ相的价电子结构进行了定量分析，通过键距差（Ｂｏｎｄ Ｌｅｎｇｔｈ Ｄｉｆｆｅｒｅｎｃｅ）方法计算了Ｆｅ２Ｂ晶体配位团各键上的共价电子数，结果表明，沿（２２０位向分布的Ｆｅ－Ｆｅ原子键最强，其共价电子数ｎＡ＝０．３８５２，键能ＥＡ－１５．７３７２ｋＪ／ｍｏｌ；沿（００２）位向分布的Ｂ０Ｂ原子键较弱，其共价电子数ｎＤ＝０．１３９２，键能ＥＤ＝４．５０５２ｋＪ／ｍｏｌ

VALENCE ELECTRON STRUCTURE OF Fe_2B PHASE AND ITS EIGEN-BRITTLENESS

The valence electron structure of Fe_2B phase was studied on the basis of Yu's empirical electron theory of solids and molecules.The values of valence electrons on every bond in an atomic coordinate cluster were calculated by the method of bond length difference(BLD). The results showed that the bonds between Fe-Fe atoms along (220] direction were strongest, of which the value of valence electrons n_A=0.3852 and the bond energy E_A = 1 5.7372 kJ / mol, The bonds between B-B atoms along [002] direction were weaker, of which n_D = 0. 1 392 and E_D = 4.5052 kJ/ mol. A space bond network of Fe_2B crystal was built,so the cause of the eigen-brittleness could be translated by a heterogeneity of the bond distribution. Comparing experimental results to theoretical analysis, it came to the conclusion that there was a conformability between them.