Abstract
Processing of synthesising nanocrystalline ZrO2(3Y) by hot-pressing was investigated. Large crack-like pores have been found in the sintered samples. The reason of this phenomenon was that the agglomerate in the powder had not been destroyed efficiently. This agglomerate sintered quickly and turned into aggregate when hot-pressing was applied. Large pores formed as a result of the interaction between the aggregate and the matrix. Since the applied pressure was limited because of the low stress tolerance of the graphite die, no plastic deformation could happen and those large pores could not be “squashed”. As a result, the densities of the samples sintered by hot-pressing were lower than by pressureless sintering at the similar sintering temperature. To overcome this shortage of hot-pressing, sinter forging was applied. Nano Y-TZP materials with grain size of about 85 nm and relative density of 99% could be obtained after sinter-forging at 1100°C for only 30 min.
