The sol-gel synthesis of barium aluminate using microwave radiation

Currently, much importance is given to alkaline earth metal aluminate, which are the basis of luminescent materials. Prominent among this class of compounds take barium alumi-nate doped with rare earth elements. Sol-gel synthesis is a promising method to obtain materials with desired properties. In recent years many scientific schools are engaged in its improvement. The main advantage of this method is the ability to control of the desired product formation. The aim of this work was to develop a method for preparing a hexagonal barium monoaluminate sol-gel method using microwave radiation, to study the process of phase formation of the desired product and determine the optimal conditions that allow to obtain a single-phase product.. The composition of the final and intermediate products was estimated using Rigaku Mini-Flex 600 X-ray diffractometer (Japan) (CuKa radiation) (measurements were taken at room temperature with the range of angles 20 from 3 to 80) and Agilent Technologies Cary 600 Series FTIR Spectrometer (made in USA) for IR-spectroscopy. The surface morphology of the final compounds was stadied by scanning electron microscopy (SEM) on a Hitachi TM 3000 (Japan) equipment at accelerating voltage of 15 kV while removing the charge from the sample (electron gun 5 · 10-2 Pa. specimen chamber: 30-50 Pa). Termoanalitical measurements of thermally untreated xerogels were performed using a NETZSCH STA 449C thermoanalyser ("NETZSCH" Germany). When using microwave radiation decreased the synthesis of time, the product structure is not disrupted. Formation of barium aluminate is a multistep process involving dissolution of the starting reactants, formation of sol, decomposition of precursor, formation of barium aluminate. According to the results of X-ray analysis of the formation of barium aluminate begins at a temperature of 650°C. Single-phase crystalline product are obtained at temperatures above 800°C. With an increase in the crystal lattice is not deformed temperature, crystallite size ranges from 289 A at 800°C to 476A at 1200°C.

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