Effect of sintering temperature on properties of Al2O3 whisker reinforced 3 mol% Y2O3 stabilized tetragonal ZrO2 (TZ-3Y) nanocomposites

In present study, effect of sintering temperature on density and hardness of 3 mol% yttria-stabilized tetragonal zirconia (referred to as TZ-3Y) composite reinforced with alumina whiskers (5, 10, 15 and 20 wt.%) has been studied. Initially, Ammonium Aluminum Carbonate Hydroxide (AACH) whiskers were added in TZ-3Y composite and transformed into alumina during sintering performed at different temperatures i.e. 1400, 1500 and 1650 °C. Results revealed that for all sintering temperatures, with increase in whisker concentration, sintered density decreased and hardness increased conversely. Maximum hardness of 14.47 GPa was achieved with 10 wt.% whiskers addition when sintered at 1500 °C. However, with addition of CTAB (1 wt.%) as deflocculating agent the hardness was further improved to 15.11 GPa. While sintering at 1650 °C a decrease in hardness was observed. It was mainly due to high temperature morphological change of whiskers i.e. transformation of whiskers into alumina rich grains.