摘要:
讨论了有关Fe-Mo共还原粉的几个理论问题。热力学计算表明,MoO3能顺利被C或CO还原。数学分析指出,若将铁粉和-325目钼粉混合并于1120~1180℃烧结,此时扩散均匀性判据值Dt/l2远小于1,Mo难以扩散均匀。而采用共还原法时,相应Dt/l2值远大于1,Mo在铁中均匀分布。精确测定了还原粉末的品格常数,纯Fe粉为0.28664nm,Fe-Mo粉力0.28673nm,由此推论Mo固溶于Fe之品格中,直径稍大的Mo原子置换了Fe原子,从而使其品格常数稍有胀大。
Abstract:
In this paper, several theoretical problems about co-reduced Fe-Mo powder are discussed. Thermodynamical results show that MoO3 or FeO·MoO3 can be reduced by C or CO easily, Through mathematical analysis of diffusion equation, it is pointed that the value of Dt/l2 could be a criterion representing the homogenity of element distribution. If it is far below one,diffusion proceeds without homogeneity. When mixed Fe and Mo powders were sintered at 1120-1180℃, Mo could diffuse into iron matrix. In the situation of co-reduced process,the corresponding value of Dt/l2 is far above one. Mc diffuses very homogeneously in iron matrix. Lattice constants of pure Fe and Fe-Mo powders were measured. It is 0.28664nm for Fe,and it is 0.28673nm for Fe-Mo. It is suggested that Mo should be solved in the lattice of Fe. The sites of Fe are partly replaced by slightly bigger atoms of Mo, therefore the lattice constant of Fe-Mo alloy powder is enlarged.
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