Engineered Systems and Oxide Phase Equilibria

Abstract

Oxides are uniquely stable against physical and chemical interactions. Their stability against reaction has been discussed in terms of their inherent stoichiometric constraints on defect formation and atomic transport which limit the progress of reaction. Their complex phase stoichiometry is a statistical limit to the probability of equilibrium phase formation and can restrict the progress of even nominally homogeneous phase transformation. The equilibrium characteristics of each reacting system predicts the long-term outcome and the engineer must design each stage of the thermal and chemical processing to minimize constraint on desirable reaction while maximizing the stability of the final product. Engineers attempt to manipulate local kinetic and chemical factors to promote a short-term result with useful ceramic properties.