Compaction and sintering behaviour of zirconia powders

Four kinds of zirconia powders are prepared in different ways. Their compaction and sintering behaviour are studied extensively. During compaction, the agglomerates or granules present in the powder are broken and/or undergo plastic deformation. The behaviour depends essentially on the strength of links between the particles. The sol-gel powders are more sensitive to the formation of hard inter-particle links during the synthesis process. So careful control is needed in order to avoid the formation of aggregates, because they favour the presence of large pores which lead to differential sintering and grain coarsening. In other cases the sintering can also be inhibited by the presence of residual impurities. A powder which has rod-like shaped agglomerates is sintered to regular microstructure.