In this study we evaluated the electrical response of ceramic compacts during dry pressing as a function of applied pressure. Semiconductive SiC powders were used for the experiments. In order to determine the influence of porosity in the ceramic powder compacts, a custom made die with an insulating outer sleeve was used to carry out dc and ac measurements. Measurements were performed as a function of loading and unloading compaction pressure. Dc measurements can only detect the combined response from the powders and the porosity. However, from the impedance spectroscopy data, two semicircles were observed in the complex impedance plot that allow separation of the two processes. One of these semicircles represents the bulk material property, while the other is likely due to the void space and interfaces. An estimate of the volume porosity at the different stages of compaction is provided.
展开▼
