Phase composition of TiO2-Coated ZrO2/Si3N4 composite

The effect of TiO2 coating on the phase composition of ZrO2/Si3N4 composite s was investigated both with pressureless-sintered samples and with hot-pre ssed ones. The formation of ZrN could be suppressed by increasing in the am ount of TiO2 coated on 3Y-ZrO2. However, the existence of TiO2 did little t o accelerate the transformation of alpha- to beta-Si3N4 When combined with small addition of Y2O3, the formation of ZrN could be further suppressed an d the a to beta-Si3N4 transformation could also be improved. The compositio nal variation of TiN grains with a rise in temperature was analyzed by usin g TEM and EDS. There was some solubility of zirconium ion into the TiN latt ice. It increased with sintering temperature and caused the XRD peaks of Ti N towards lower angles. (C) 1999 Elsevier Science Limited. All rights reser ved.