Formation of strontium-doped lanthanum manganite (La 0.8Sr 0.2MnO 3) by mechanical milling without media balls

Abstract

This paper reports a study of the phase evolution induced by mechanical milling of a mixture of industrial grade La 2O 3, SrCO 3 and Mn 3O 4 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 La 2O 3, SrCO 3 and Mn 3O 4 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 SrCO 3. 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.