MICROSTRUCTURE CHARACTERISTICS OF SOME POLYCRYSTALLINE OXIDE COMPOUNDS PREPARED BY SOL-GEL-SELFCOMBUSTION WAY FOR GAS SENSOR APPLICATIONS

摘要

According to sol-gel-selfcombustion method, the reacting substances are metal nitrates and ammonium hydroxide, the coprecipitation takes place into a colloidal medium and the reaction for ferrite synthesis is a quick combustion. By such a method and using an adequate heat treatment we have successfully prepared fine grained spinel ferrites and M-type hexaferrites. Structural characteristics of the heat treated samples by X-ray diffraction and SEM were studied. It was shown that small particle sizes, of about 100 nm, can be obtained. The experimental results have proved that the present method is an effective procedure to elaborate fine, chemically homogeneous and pure ferrite powders at a lower temperature than that of the conventional mixed-oxide method.