Reaction synthesis of MoSi2 from high purity elemental powders
1992; Pergamon Press; Volume: 27; Issue: 4 Linguagem: Inglês
10.1016/0956-716x(92)90199-o
ISSN1873-2712
AutoresD. A. Hardwick, Patrick Martin, Roxanna Moores,
Tópico(s)MXene and MAX Phase Materials
ResumoThis paper reports that Molybdenum disilicide (MoSi{sub 2}) is an intermetallic compound that combines a high melting point (2293K) with excellent resistance to high temperature oxidation. With respect to mechanical properties the behavior of polycrystalline MoSi{sub 2} falls into one of three regimes, based on the sue temperature: t {lt} 925{degrees} C: strong + brittle; 925 {lt} T {lt} 1250{degrees} C:strong + ductile and T {gt} 1250{degrees} C:weak + ductile. The majority of recent investigations have focused on the properties of MoSi{sub 2}-based materials processed from commercially available powder. Commercial MoSi{sub 2} powder contains significant amounts of oxygen; for example, a chemical analysis of powder obtained from Cerac Inc. revealed an oxygen content of 0.6 wt%. Consolidation of such powder resulted in a substantial volume fraction of amorphous silica in the final product. MoSi{sub 2} powder produced by the crushing and grinding of arc-melted elemental Mo and Si also exhibited amorphous Si-rich particles after vacuum hot-pressing at 1973K and 30MPa. Grinding of the cast material to powder was done in ethanol but one this was driven off, the powder was air-handled. The high energy mechanical alloying in an argon atmosphere of elemental Mo and Si powder to produce MoSi{sub 2}more » has also been investigated. Following hot pressing, the MoSi{sub 2} made in this fashion still contained a substantial volume fraction of SiO{sub 2}.« less
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