Abstract
The effect of bimodal particle size distribution on the sintering of magnesium oxide (MgO) powder was examined using seven kinds of powders with average primary particle sizes of 11, 25, 32, 44, 57, 107, and 261 nm. The binary-phase MgO powder mixtures were prepared using two of these MgO powders (quantity : 0.75 g for each powder). These binary-phase MgO powder compacts were fired at 1700°C for 5 h in air. The relative densities of the sintered binary-phase MgO powder compacts were lower than those (97-98%) of the sintered single-phase MgO powder compacts. Appreciable decreases in relative density were observed after the firing of binary-phase MgO powder compacts with average primary particle sizes below 57 nm. The densification of such binary-phase MgO compacts appeared to be restricted by the entrapment of pores into grains, due to the rapid inhomogeneous grain growth.
