Study of the post-annealing effect for the MoSi2 compound

Study of the post-annealing effect for the MoSi2 compound

The low-temperature oxidation of the MoSi2 compound prepared by a self-propagating high temperature synthesis (SHS) reaction from a mixture of Mo and Si powders has been investigated by comparing the structural and chemical destructions of the MoSi2 compound. One of the comparable samples was a pellet sintered at 1700℃ and the other was synthesized powder annealed at 400℃ in air. The phase structure, microstructures, and chemical states of the samples were measured by XRD, SEM, and XPS. From the results of the analysis, the powder synthesized by SHS had a body-centred tetragonal MoSi2 crystal structure together with SiO2 and MoO3 amorphous phases from air contamination, the sample sintered at 1700℃ had a similar crystal structure to synthesized powder. On the other hand, the crystal structure of the powder annealed at 400℃ was destroyed completely into amorphous SiO2 and crystalline MoO3 phases and the loss of Mo content occurred by volatilizing MoO3.

The low-temperature oxidation of the MoSi2 compound prepared by a self-propagating high temperature synthesis (SHS) reaction from a mixture of Mo and Si powders has been investigated by comparing the structural and chemical destructions of the MoSi2 compound. One of the comparable samples was a pellet sintered at 1700℃ and the other was synthesized powder annealed at 400℃ in air. The phase structure, microstructures, and chemical states of the samples were measured by XRD, SEM, and XPS. From the results of the analysis, the powder synthesized by SHS had a body-centred tetragonal MoSi2 crystal structure together with SiO2 and MoO3 amorphous phases from air contamination, the sample sintered at 1700℃ had a similar crystal structure to synthesized powder. On the other hand, the crystal structure of the powder annealed at 400℃ was destroyed completely into amorphous SiO2 and crystalline MoO3 phases and the loss of Mo content occurred by volatilizing MoO3.