Abstract
Dense and fine grained yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) were fabricated by a two-step sintering technique. The Y-TZP powder compact was heated up to a temperature (T1;1300°C, 1350°C, and 1400°C) where the sintering set in the intermediate stage, and then was cooled down and held for 20 h at a temperature (T2) which was 10°C to 150°C(ΔT:T2-T1) lower than T1. The relative densities were kept being around 96% at T1= 1300°C over the ΔT range of 0-40°C, whereas they were around 98% over the ΔT range of 0-50°C at 1350°C and over the range of 0-100°C at 1400°C. The average grain sizes were as low as 0.25-0.3 μm and the grain growth was inhibited compared to the case of single-step sintering, i.e., the heating up to the desired temperature (T1), holding for 20 h, and then cooling down to room temperature.
