Effect of powder bed on the microstructure and electrical properties of Bi2O3- and Sb2O3-doped ZnO

The effects of powder bed on the microstructure and electrical properties of Bi₂O₃- and Sb₂O₃-doped ZnO specimens are investigated in the present study. By using a sufficient amount of powder bed, the weight loss of Bi₂O₃ reduces from >95 to <20%. The reduction of weight loss enhances significantly the densification and grain growth of ZnO. Furthermore, the use of powder bed can also reduce the size distribution of ZnO grains. Nevertheless, the presence of Bi₂O₃ residue results in the formation of a pyrochlore phase (Zn₂Bi₃Sb₃O₁₄) during the cooling down stage; its presence is detrimental to the nonlinear characteristics of ZnO–Bi₂O₃–Sb₂O₃ system.