Microstructural evolution in nanocrystalline Y-TZP containing a silicate glass

Nanocrystalline yttria stabilized tetragonal zirconia polycrystal (NC-Y-TZP ) powders were coated with a sodium strontium silicate glass using the sol- gel technique. The compact powders were sintered at 1400 C for 1 h resultin g in dense nanocrystalline pellets with 5, 10 and 15 vol.% glass. Short pre -sintering heat treatment at 800 C caused the full stabilization of the tet ragonal phase while long treatments led to the devitrification of the glass y phase. The mean grain size decreased from 196 run in the glass-free speci men to 140, 110 and 100 mn in the specimens containing 5, 10 and 15 vol.% g lass, respectively. The grain size distribution width also decreased with i ncrease in the glass content. TEM revealed the morphological changes of the highly facetted polyhedral grains in the glass-free specimens into the rou nd-shape grains with increase in the glass content. The effect of the glass on the phase formation, densification and microstructure have been discuss ed. (C) 2001 Elsevier Science Ltd. All rights reserved.