Structural, elastic, thermophysical and dielectric properties of zinc aluminate (ZnAl2O4)

Dense zinc aluminate (gahnite) ceramics have been prepd. at different sinter temps. ranging from 1200 to 1600 DegC from zinc aluminate powder prepd. via the solid-state synthesis. A max. achieved relative d. of 93% was achieved. Several bulk properties like Young's modulus, heat capacity, thermal diffusivity and cond. have been detd. and estns. of the bulk properties at 100% d. are made. Furthermore, in spinel-type materials like zinc aluminate the process of cation inversion occurs, which is in general not taken into account in computer simulations for the prediction of bulk properties. In order to det. whether the amt. of cation inversion can be influenced by the prepn. method resulting in different bulk properties, zinc aluminate powders were synthesized using solid-state synthesis, co-pptn. and a sol-gel method at different temps. The resulting powders were zinc deficient due to the volatile nature of zinc at the calcining temps. The cation inversion of these powders was investigated using solid-state MAS 27A1 NMR indicating that the cation inversion is very small for pure zinc aluminate irresp. of the prepn. method.