Abstract
By measuring the electrical resistance of tantalum filaments (i) during isothermal reaction with oxygen, (ii) after isothermal degassing, and (iii) after rapid temperature quench, we infer both the instantaneous dissolved oxygen concentration and the metal “gasification” rate. For the conditions: 1.6 × 10–2⩽p(oxygen)⩽ 0.67 Pa, 2400 K ⩽Tw⩽ 2800 K, the following mechanistic conclusions are drawn concerning the production/desorption of metal oxides [TaO(g), TaO2(g)] and the cause of the observed enhanced reactivity of microwave discharge-produced atomic oxygen: (a) under conditions of steady-state O(abs)-concentration and oxide desorption rate, the mechanisms of metal oxide production/desorption in dissociated and undissociated gaseous oxygen are identical; (b) enhanced chemisorption probability accounts for increased oxygen coverage and tantalum volatilization rate in atomic oxygen. Part 2 includes the extraction of elementary rate constants for interface penetration and oxide desorption based on transient electrical resistance data following the isothermal exposure of tantalum to step-function increases in oxygen pressure.
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 callMore From: Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases
Disclaimer: 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.
