抄録
Among the carbides, the nitrides, the borides and the silicides of the transition metals, molybdenum disilicide has been less studied upon than the others, though its samples are rather easily available as refractory hard metal pieces. It is, however, relatively difficult to prepare pure samples of the compound, as the vapor pressures of Mo and Si differ much from each other (the vap. press. of Si: 1mm Hg at 1, 219°C according to I. C. T.). After examining the conditions for preparing solid MoSi2 by powder method, we succeeded in obtaining samples of high purity MoSi2 (99.6%), which we subjected to X-ray and chemical analysis. In experimenting for the effects of the following factors, namely, the particle size of the powders, the duration of the mixing time, the temperature and the atmosphere of reaction and the ratio of mixture to reaction kinetics, we found that the most important condition is to add several percents more of Si than is stoichiometrically evaluated prior to the process, as explained in § III-3-(4) and Fig. 4 and 5 below.
