Abstract
The kinetics of formation of a corrosive oxide layer of apparently unlimited thickness during the interaction of oxygen with a polycrystalline tungsten filament at temperatures between 500 and 1000°K has been investigated by line-of-sight flash desorption mass spectrometry. The major desorption product from this multilayer oxide film is WO2, which desorbs over the temperature range 1000–1300°K. The rate of formation of the oxide film was shown to be directly proportional to the oxygen gas phase pressure at pressures ≲ 10−4 torr. A study of the temperature dependence of the oxidation rate revealed that the formation of the WO2-producing oxide layer proceeds through two distinct steps; these occur subsequent to the first three stages in the interaction of oxygen with W characterized in Paper I. In the final state of oxidation, the rate is shown to be independent of the thickness of the oxide film. The results are in qualitative accord with the theoretical model of Mott. Desorption of the oxide film is a zero order process, with a desorption activation energy of 420 kJ mol−1.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
