WSi_2的价电子结构及其性能研究

Study on the Valence Electronic Structure and Properties of WSi_2 Phases

根据固体与分子经验电子理论,通过键距差(BLD)方法,计算了金属间化合物WSi2的价电子结构和理论结合能。结果表明,WSi2理论结合能为1859.5kJ/mol,与实验值吻合。WSi2晶体中,沿<331>位向分布的W—Si键的键能最大,EA=33.397kJ/mol,且有32个等同键数,是晶体熔化时必须破坏的主干键络,因而WSi2具有高熔点。WSi2晶体中含有较高密度的晶格电子,使WSi2具有良好的导电性。WSi2晶体中键络分布不均匀性是导致晶体脆性的主要原因。

According to the empirical electron theory of solid and molecule, the valence electron structure and theoretical cohesive energy of WSi2 were calculated by the BLD method. The results show that theoretical cohesive energy of WSi2 is 1859.5 kJ/mol, which agrees well with the experimental data. The strongest bonds in the unit cell of WSi2 are W-Si bonds along 〈331〉 direction, which are the main bond networks that must break down when the crystal melts, of which the bond energy is 33.397 kJ/mol and the number of identical bond is 32, therefore resulting in high melting point of WSi2. There are lattice electrons with higher densities in WSi2, which accounts for the good conductivity of WSi2. Also, it is speculated that the brittleness of WSi2 can be explained primarily by a heterogeneity of bond distribution.