Initial Sintering of Bi₂O₃ Powder Compacts

Abstract

The effect of particle size and impurity on initial sintering of Bi₂O₃ was investigated in the range 550° to 700°. The isothermal shrinkage rate was analyzed by four different kinetic equations.
The sintering of Bi₂O₃ with the grain size larger than 2μ was controlled by grain boundary diffusion mechanism and quick aggregation or adhesion of particles was observed for fine powder Bi₂O₃ (0.2μ). The activation energy for grain boundary diffusion was 140 to 150kcal/mol and it was presumed that the sintering rate determinant or slow diffusion species was O^2- ion. Remarkable promotive effect on sintering was observed for CdO added Bi₂O₃ powder compact, while addition of CeO₂ suppressed much the rate of sintering.