A solid state diffusion model is formulated to examine the permeation of gases through zirconia microspheres formed during the short duration (~200 msec), high temperature (3000 to 4000K) reaction of zirconium with controlled mixtures of nitrogen and oxygen (N2/O2 = 0.025, 625 torr). The model assumes:(1) the existence of equilibrium-composition zirconium dioxide at 3000K, (2) oxide-gas interface equilibria, (3) diffusion by motion of lattice vacancies, and (4) nitrogen and oxygen equivalence in oxide permeation. Numerical solution of the gas permeation equa¬tion provides the pressure inside a microsphere as a function of time. The time frame examined is 10-3 to 1 sec at 3000K.
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