| MoSi₂ is a very promising high temperature structure material for its excellent oxidation resistance and mechanical properties at high temperatures with relatively low weight. For the extensive use of MoSi₂, however, problems such as pesting, disintegration of MoSi₂ during oxidation, should be taken care of. The initial step of posting in MoSi₂ is reported to occur by a simultaneous oxidation of Mo and Si, with some variation on the oxidation temperature. To investigate the posting in MoSi₂, this study focused on the simultaneous oxidation temperature of Mo and Si and the nucleation and growth of oxides formed at 593∼793 K. In this study, MoSi₂ was produced by spark plasma sintering(SPS) and then oxidized at 593∼1093K. The simultaneous oxidation of Mo and Si took place below 893 K while selective oxidation of Si occurred above 993 K. The weight gain of MoSi₂ was the highest at about 693 K. SEM analyses of the specimens oxidated at 693 K showed a lot of MoO₃, most of which were believed to be preicipitated at or around defects in matrix including SiO₂ particles. |
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