Characterization of Two-Phase Dispersions by IS

In the systems discussed so far, the continuous phase was concentrated in grain boundary regions, such that its blocking properties were noticeable, even at low volume fraction. This sub-section covers two-phase dispersions, where the volume fractions of continuous and discontinuous phase are closer, for example 0.70 and 0.30. Two examples are discussed, one where the time constants of the phases are well resolved, and another where they are not. 

Characterization of a Two-phase Alkali Halide System. Alkali halide 

In the above system, the analysis was possible because the relaxation frequencies of the matrix and dispersed phases differed by a factor of about 30. In other cases, it is impossible to identify the relaxations of individual phases due to prox- 

This approach has been used by Bonanos et al. [1984a] to study PSZ of composition ZrOa with 8 mole % CaO (Ca-PSZ). XRD and TEM showed the t m transformation to be complete after 20 h of heat treatment at 1400°C, while quantitative x-ray diffraction analysis gave a value of 0.3 for the volume fraction of the t component. Electron microscopy showed the t particles to be ellipsoidal, with axial ratios alb and bic of -2, for which Table 4.1.2 gives the corresponding form factors, 01 = 7.9, 02 = 2.5, 03 = 0.66. In short the parameters 0 and X2 in Eq. (23) are given and the only remaining variables are the complex conductivities Xjfi, Xff2, and y, . 

From a microstmctural analysis and from the evolution of r, aging was found to occur in three stages. 

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