Investigation and Sintering of Nano-manganite Ceramic Powders Prepared Via Different Methods

Abstract

During the last decade ABO3 manganites with perovskite structure exhibit a widely studying due to its physical, magnetic and electric properties that improve their various applications like sensors, catalysts electrode materials for solid-oxide fuel cell. This work concerns on studying: 1) the effect of various cation substitution such as Ca and Sr cations on phase and microstructural of LaMnO3 phase and 2) the role of these cation on changing electrical, physical and magnetic properties of such material. Two different ways of preparation have been applied i.e. a hydrothermal method and mechanical activation method in this work. In hydrothermal synthesis, the crystalline powder can be prepared in one step from solutions of metal salts at a temperature of 230 °C in 48 h. On other hand, the mechanical activation method are carried out by preparation the metal oxides depending on using manganese oxide that were extracted from low-grade ores by using glucose as a reducing agent in dilute nitric acid. Then the prepration of perovskite manganite samples by milling and mixing the reactant metal oxides with the extracted MnO2 has been carried out and then added to other various oxides to prepare manganite compounds. In all the samples the Perovskite manganites have been prepared in a general formula LaxCa1-xMnO3 and LaxSr1-xMnO3 (x = 0.1, 0.3, 0.5 and 1.00) and then sintered at different temperatures ranging from 1100oC to 1450oC. The powder characteristics of metal-doped lanthanum manganites are characterized utilizing x-ray diffraction to elucidate the phase transformation, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) were used to elucidate