Development of spinel magnesium aluminate by modified solid state process and its characterization

Abstract

Spinel magnesium aluminate synthesis by modified solid state process using AR grade oxide precursors in stoichometric (1:1) ratio was used after mild activation carried by agate-mortar pestle in dry condition. Thermal analyses were carried off for the mixed activated powder to determine the zone for phase formation (spinelization) which plays a pivotal role for annealing temperature selection. Followed by phase transition studied from thermal analyses, heat treatment of powders (annealing/sintering) in air was carried at various temperatures of 900˚C, 1050˚C and 1150˚C for variable durations. Phase development was confirmed after XRD analyses while FTIR determine the bonding of compound as well as required M−O coordinations for the required phase formation. Morphological analyses of annealed powders by SEM, FESEM represent dense agglomerates with fine particulates of spherical to hexagonal shape, irregular polygon with negligible interconnected porosity. Electronic transition of the compound developed was studied by UV–VIS followed by band gap estimation using Tauc relation. Band gap of the compound evolved was noted to be varying with temperature and soaking period.