Formation of strontium-doped lanthanum manganite (La0.8Sr0.2MnO3) by mechanical milling without media balls

This paper reports a study of the phase evolution induced by mechanical milling of a mixture of industrial grade La2O3, SrCO3 and Mn3O4 powders under a humid atmosphere. In this milling, no media balls were employed and the mechanical activation was applied through friction among particles in the powder mixture. Under humid atmosphere (relative humidity 70% at 25°C), X-ray diffraction peak intensities of La2O3, SrCO3 and Mn3O4 decreased, and the specific surface area of the powder mixture increased at the early stage of the milling (less than 10 min). In further milling, the perovskite strontium-doped lanthanum manganite (LSM) started to appear. Differential thermal analysis suggests that the present mechanical activation brought about the decomposition of SrCO3. Single-phase LSM was obtained by annealing of the milled powder mixture at a relatively lower temperature of 900°C and its particle size was about 100 nm. The present mechanical milling resulted in considerably lower contamination release from milling media.