【摘 要】
：
The (Mol-xNbx)Si2 (0≤x≤0.5) was successfully prepared using the combustion synthesis method by Mo, Nb, and Si elemental powders.The influences of niobium on the combustion mode, combustion temperature
【出 处】
：
2012 Postdoctoral Symposium of China on Materials Science &
论文部分内容阅读
The (Mol-xNbx)Si2 (0≤x≤0.5) was successfully prepared using the combustion synthesis method by Mo, Nb, and Si elemental powders.The influences of niobium on the combustion mode, combustion temperature, combustion velocity and products were investigated.With the increase of Nb content, the combustion temperature of Mo-Nb-Si system increases, while the combustion velocity reduces from 4.977 mm/s to 1.988 mm/s.When the x is less than 0.09 in (Mol-xNbx)Si2, all the Nb substitutes Mo in MoSi2 during the SHS and the combustion products exhibit C 1 lb tetragonal MoSi2.However, C40-type structure of NbSi2 appears when x=0.09 and increases with further increase of Nb content.The non-equilibrium SHS process makes supersaturated solid solution effect of Nb to MoSi2, resulting in the continuing expands of the lattice of MoSi2 even when the niobiums amount is far more than its solid solubility limit in Cllb phase of MoSi2.By combustion front quenching technique, it can be found that silicon particles melt during the combustion reaction and the combustion products are formed through melting, dissolution and precipitation mechanism in SHS synthesis.
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