Influence of texture on electrical properties of ZnO ceramics prepared by extrusion and spark plasma sintering

An extrusion-spark plasma sintering (SPS) process was successfully utilized to obtain a textured, near full dense homogeneous bulk ZnO ceramics. Rod-like, anisotropic ZnO particles were extruded and sintered, and highly c-axis-preferred orientation was obtained in the bulk ZnO, which can be called as fiber texture. The textured bulk ZnO showed more low-angle grain boundaries compared with that without texture. It was found that the highly preferred orientation decreased the electrical resistivity obviously in the bulk ZnO at room temperature. The observed high proportion of low-angle grain boundaries due to the texture resulted in a quite lower resistivity in grain boundaries at room temperature, which was the main reason for the reduction in electrical resistivity of the textured bulk ZnO ceramics.