Stabilization of high temperature hexagonal phase of SrAl2O 4 at room temperature: Role of ZnO

Abstract

Strontium aluminate (SrAl2O4) exhibits a monoclinic structure at room temperature (RT) and transforms to a hexagonal structure at above 650°C, reported previously in the literature. In this article, we have shown a stable, high temperature hexagonal phase of SrAl2O 4 (SAO) at RT by synthesizing a SAO-ZnO composite through a combustion technique. While SAO crystallizes in the monoclinic phase by adding 2.5 wt% of ZnO, a stable hexagonal phase of SAO at RT has been obtained for 20 wt% of ZnO. Further, the hexagonal phase of SAO transforms to a monoclinic phase after increasing the calcination temperature from 700 to 1200°C. The role of ZnO in determining the structure and photoluminescence properties of these composites are discussed. This journal is © the Partner Organisations 2014.