The effects of TEOS on the microstructure and phase evolutions of YAG phase by formation of alumina/yttria core‐shell structures

Abstract

AbstractIn this work, pure yttrium aluminum garnet was obtained by the partial chemical method at the low temperature. In this approach, alpha‐alumina nanoparticle, yttrium nitrate, urea, and tetraethyl orthosilicate (TEOS) were used as Al3+, Y3+, precipitation agent, and both dispersant and phase formation assistant agents, respectively. The results showed that TEOS molecules as a dispersant agent caused the less agglomeration of the alumina‐yttria core‐shell structure with a diameter of 200‐300 nm, as compared to particles obtained without using TEOS molecules. Furthermore, by using 0.5 and 1 wt% of TEOS, the YAG formation temperature was decreased from 1400°C to 1200°C through the liquid‐phase diffusion mechanism. Thus, in this case, the TEOS molecules acted as phase formation assistant agent for the constitution of YAG phases.