Obtaining calcium and terbium manganites by the combustion method

Abstract

This work presents the synthesis and characterization of calcium and terbium manganite (TbₓCa₁₋ ₓMnO₃) which was obtained by the combustion synthesis method. Manganites were obtained starting from precursor salts of Ca(NO₃)₂.4H₂O [0.65 M], Mn(NO₃)₂.H₂O [1 M] and Tb(NO₃)₃.5H₂O [0.35 M], using Urea as fuel ( CO(NH₂)₂) and as dispersing medium 50 mL of deionized water. The reaction process was carried out in a muffle at 605°C, the resulting product was allowed to cool to room temperature, the powders obtained were pulverized with a manual mortar, which were subjected to calcination at 600°C, after which they were treated thermal at 1000°C. Subsequently, its crystal structure was determined by X-ray diffraction (XRD), its distribution and particle size by particle size analysis (ATP), respectively. The results were compared with those obtained previously when synthesizing this same manganite, but by the co-precipitation method, finding visible differences. The X-Ray Diffraction results showed that TbₓCa₁₋ₓMnO₃ and some other secondary phases in the form of oxides were obtained by both methods, which suggests changing the synthesis variables until the pure phase is obtained. By means of ATP it was possible to observe that particle sizes with an average of 79.08 µm were obtained by the combustion method, and 84.13 µm by the co-precipitation method, respectively.