Preparation of Nanocrystalline Molybdenum Disilicide (MoSi2) by a Chlorine-Transfer Reaction
journal contributionposted on 13.09.2001, 00:00 by Timothy J. Trentler, R. Suryanarayanan Iyer, Shankar M. L. Sastry, William E. Buhro
Reaction of MoCl3 and Si at 500 °C produces phase-pure MoSi2 powders in near-quantitative yields. Use of an inert diluent (LiCl or ZnCl2) enables the production of nanocrystalline powders. The diluent can be subsequently removed by washing with methanol or by sublimation. Consolidation of diluent-free powders by hot pressing at 1400 °C and 375 MPa for 0.5−4 h affords dense compacts (>95% theoretical density) possessing nanocrystalline grains (<50 nm) and exhibiting hardnesses of 15.0−16.3 GPa. This constitutes a 60−75% enhancement in hardness over conventional, microcrystalline MoSi2.