High‐Temperature Oxidation of Molybdenum Disilicide
Tóm tắt
The oxidation of MoSi2 in air at atmospheric pressure was studied by electron diffraction, X‐ray diffraction, and thermogravimetric analyses. The oxidation process occurs in two parts: (1) formation of MoO3 and SiO2 at temperatures below the boiling point of MoO3, and (2) formation of Mo5Si3 and SiO2 at higher temperatures. Evidence is presented which indicates that oxygen permeation through a silica layer, which may be of a mixed crystalline‐glassy nature, controls reaction rate at high temperatures and that Mo5Si3 is present directly beneath the protective oxide. The activation energy for oxidation of MoSi2 above 1200°C was calculated as 81.3 kcal mole−1.
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Tài liệu tham khảo
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