Effect of MxOy (M= Si, Ti, Ca, Mg) Dopants on Solid-State Sintering of Yttrium Aluminium Garnet

Abstract

Polycrystalline Yttrium Aluminium Garnet (YAG) ceramic has been prepared by solid-state reactive sintering route. Nano-sized Al2O3 (120nm) and Y2O3 (100nm) powders along with
0.1 wt.% of the oxide dopants (SiO2,TiO2,CaO,MgO) were mixed through ball milling, pelletized and sintered at different sintering temperatures such as 1350oC, 1450oC, 1550oC and 1650oC with varying amount of soaking time for each peak temperature. X-ray diffraction analysis has been carried to identify the phase transformation and change in crystallite size of the samples with varying temperature, time and dopant used. Scanning Electron Microscopy was done to study the morphology and grain size dependence of the synthesized YAG ceramic on the sintering parameters and type of dopant used. Dilatometry was carried out with powder precursors to track the transformation of low temperature phases such as YAM, YAP to YAG phase. Other characterizations such as Bulk Density, Apparent Porosity and Shrinkage measurements were done to study the amount of densification and pore concentration achieved specific to the dopant used at different sintering temperatures.