The Oxidation of Oxygen-Deficient Zirconia and Its Relationship to the Oxidation of Zirconium

Abstract

Upon heating black oxygen‐deficient zirconia in oxygen of atmospheric pressure to 450° to 900°C, oxygen is taken up. The increase in the thickness of a white layer of virtually ideal composition with time follows a parabolic rate law, . The rate constant is about two orders of magnitude higher than Tammann's rate constant for the increase in thickness of a layer during the oxidation of zirconium metal. Equations for the concentrations of ionic and electronic defects in zirconia as functions of the oxygen partial pressure are presented in order to derive theoretical equations for the rates of oxidation of oxygen‐deficient zirconia and of zirconium metal.