Spinodal Decomposition in Tetragonal Systems: SnO2-Tio2

Expressions are given for the coherency-strain elastic free energy of systems with tetragonal symmetry in the framework of the continuum theory. This theory is applied for SnO2-TiO2 and the results are compared with known experimental observations. Calculations for other tetragonal systems are also presented. Finally, the results of these calculations for systems of tetragonal symmetry are discussed in the light of the Cahn and Hilliard theory of spinodal decomposition.