Comparative Studies of The Effect of Particle Size on the Microstructural Characteristics of Bi2O3 and Sb2O3 Additives on Sintered Zno Ceramics

Two different powder samples of ZnO with minuscule additives, of Bi2O3 and Sb2O3 were prepared through ball milling, in solutions containing deionized water and polyvinyl alcohol (PVA) using zirconia balls. The powder samples were sieved to obtain particle size ranges of ≤ 38μm (Z, ZB, ZBS) and ≤ 63μm (Z1, ZB1, ZBS1). The sample pellets were sintered at 800℃/60mins and 1100℃/600mins and their microstructures examined using SEM and X-ray for densification and coarsening kinetics. Grain growths were observed for samples ZB and ZB1 at both temperatures due to the formation of bismuth-rich liquid phase, whereas for ZBS and ZBS1 grains growths were hindered because of the enclosure of spinel phase which pinned grain boundary motion. SEM micrographs show high densities for particle size range of ≤ 38μm at both temperatures, while for particle size range of ≤ 63μm, densification was highest at 1100℃/600mins.The decisive parameters which controlled densification were found to be temperature, sintering time and particle geometry. In the cases where all three parameters were utilized (Z, ZB, ZBS at 1100℃/600mins), denser materials were obtained. Also equal masses of representative samples of ZB and ZB1 were seen to be electrically comparable from the nonlinear plot.