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High‐Temperature Oxidation of Molybdenum Disilicide
Author(s) -
WIRKUS C. D.,
WILDER D. R.
Publication year - 1966
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1966.tb13227.x
Subject(s) - thermogravimetric analysis , molybdenum , oxide , molybdenum disilicide , activation energy , materials science , oxygen , boiling point , atmospheric pressure , analytical chemistry (journal) , chemistry , chemical engineering , inorganic chemistry , mineralogy , metallurgy , organic chemistry , oceanography , geology , engineering
The oxidation of MoSi 2 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 MoO 3 and SiO 2 at temperatures below the boiling point of MoO 3 , and (2) formation of Mo 5 Si 3 and SiO 2 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 Mo 5 Si 3 is present directly beneath the protective oxide. The activation energy for oxidation of MoSi 2 above 1200°C was calculated as 81.3 kcal mole −1 .