EFFECT OF PRESSING METHOD ON ORGANIC BURNOUT

Sintered Y-TZPs formed using cold isostatic compaction exhibit a lower sintered density and more porosity than ceramics formed using conventional uniaxial die compaction, although the isostatically pressed powder compact has a higher and more uniform green density. For the 3 wt% PEG1500-doped zirconia powder, the sintered density decreases in a near-linear manner with increasing isostatic pressing pressure. It was identified that the low sintered density and the poor microstructure were due to the incomplete burnout of PEG1500 at the low and intermediate temperatures when the powder compacts were heated at a rate of 3-degrees-C/min. The delayed organic burnout at temperatures close to and/or at the sintering temperature results in the formation of largely swollen intergranular pores.