Sintering of MoSi2 by reacting (Mo+Si3N4) compacts

The possibility of formation of dense MoSi2 has been studied by reacting Mo and Si3N4. Powder mixtures of Mo and Si3N4 were taken in a molar ratio (Mo:Si3N4 = 1:1 or 3:2), according to the following reactions: (Mo + Si3N4RTMoSi2 + 1/3Si3N4+4/3N2 or 3Mo+2Si3N4RT3MoSi2+4N2). The cold pressed compacts were reacted at different temperatures (1400, 1453 and 1480DGC) in carbon resistance furnace and under nitrogen. MoSi2 was the major phase after reaction at all temperatures. In Mo+ Si3N4 compact, MoSi2-Si3N4 composite was formed at 1400DGC. The excess Si3N4 was decomposed and formed elemental Si after reaction at 1453 and 1480DGC. In (3Mo + 2Si3N4) system as there was no excess Si3N4, lower silicides of Mo, i.e. Mo5Si3 and Mo3Si were formed at all temperatures. Neither Si nor SiC was formed in the 3Mo+ 2Si3N4 system.