An enhanced understanding of the microstructure of oxide ceramics will help scientists and engineers improve their efficiency and design. A phase-field model for the composition and phase distribution of the oxide ceramic components is studied. The model, which includes an obstacle in the phase portion of the energy potential, results in a minimisation problem that characterises the distribution of the bulk phases. The transition region between them is studied in several mathematically plausible asymptotic limits. The behaviour of the system in these limits provides insights into the applicability of the model and indicates appropriate parameter regimes.

The crystal structure of several compounds of Ca1−xSrxZr4(PO4)6 ceramics has been investigated by X-ray powder diffraction at room temperature. All compounds form a solid solution with a unique unit cell. While the lattice parameter a of the hexagonal unit cell decreases of about 0.9% with increasing Sr content only slightly, it considerably elongates in c direction (2.8%). No structural transformation has been observed by high-temperature X-ray diffraction up to 1000 °C.