Dielectric properties of aluminium nitride–γ-alon materials

The self-propagating high-temperature synthesis (SHS) method and hot-pressing were used to prepare materials composed of aluminium nitride and aluminium oxynitride with spinel structure – γ-alon. The chemical composition of the hot-pressed powders decided on phase composition of the sintered samples and structural properties of both phases. Dielectric loss and dielectric constant were measured as a function of frequency. For all samples frequency changes of tan δ fulfilled an inverse power-law. Such behaviour and the vales of tan δ were independent of the phase composition of the samples. For the low frequencies the ɛ values decreased continuously with increase of frequency and then they were independent of it. Increase of the γ-alon content in the samples caused increase of their dielectric constants.