材料期刊网

利用最近发表的固体与分子经验电子理论,根据已有的晶体结构资料,对ε-Fe_3C的价电子结构进行了分析。通过键距差分析和原子磁距等两方面的论证得出 结论:1.在ε-Fe_3C中,碳原子处于第6杂阶,Fe原子处于甲种杂化的第11阶; 2.它具有n_4(Fe-c)键,且有n_A=0.8440;3.n_A键在空间分布极为规则,形成三维的规则的网状结构,预期该结构应有大的机械强度和低温稳定性;4.就机械强度和硬度来说ε-Fe_3C可能比渗碳体Fe_3C小些,但由于前者的n_A键比后者在空间分布更为均衡,故ε-Fe_3C可能不像渗碳体Fe_3C那样脆。

The valence electron structure ofε-Fe_3C was studied on the basis of recently published Yu’s“empirical electron theory of solids and molecules”and corresponding known crystallographic data. It seems that the discussion about both the analysis of the bond length differences and the magnetic moment of atoms may warrant such conclusions:(1)The Fe and C atoms inε-Fe_3C are of step A-11 and 6 respectively;(2)There exist n_(A(Fe-C))bond and n_A=0.8440;(3)The space distribution of n_A bonds forms regularly a 3-dimension network structure. It is estimated that this is the structure of higher mechanical strength and low-temperature stability;(4)Although the mechanical strength and hardness ofε-Fe_3C may be inferior to that of cementite Fe_3C, yet the former will be not so brittle as the latter owing to their more regular space distribution of n_A bonds.