Effect of composition of starting materials of Mo-Si on self-propagating high temperature SHS reaction

摘要

An experimental study of the self-propagating high temperature synthesis of Mo-Si alloys was conducted from elemental powder compacts. Test specimens with seven compositions, including Mo/Si = 1 :1-25, 1:1-50, 1:1-75, 1:2-00, 1:2-25, 1:2-50 and 1:2-75 respectively, were employed. Experimental evidence showed that a combustion wave featuring a spinning reaction zone can be observed. When the powder compacts are from Mo:1-25Si to Mo: 1-75Si, the combustion temperature and the propagation velocity of combustion wave increase with increasing silicon in the sample, and the combustion products are composed of MoSi_2, Mo_5Si_3 and Mo. However, when the powder compacts are from Mo: 2-25Si to Mo: 2-75Si, the combustion temperature and the propagation velocity decrease rapidly as the silicon in the compact increases, and the combustion products are composed of MoSi_2 and Si.