Articles techniques et présentations

This paper studies multicomponent transport through zirconia, assuming a chemical reaction involving electrons and oxygen vacancies defects. Classically, according to the Wagner theory for ambipolar diffusion, the electroneutrality condition in the oxide is considered. Therefore three constraints must be satisfied on the transport problem: oxide stoichiometry, electroneutrality and the source term coming from chemical reactions. The stoichiometry constraint prevents to solve the problem with the Nernst-Planck equation as implemented in COMSOL Multiphysics. This work is focused on a method to reduce the problems in just one transport equation keeping all constraints on the system. Simulation results from this modeling are linked to experimental oxide growth kinetics and discussed in the framework of available data in the literature.