CLEAN EFFECTIVE METHOD OF SYNTHESIS OF CRYSTALLINE PEROVSKITE POWDERS LACOOIN AIR, FROM OXIDIC PRECURSORS

摘要

The invention relates to a clean efficient method for preparing perovskite nanopowders of LaCoOtype from oxidic precursors of lanthanum and cobalt, the resulting nanopowders exhibiting high crystallinity degree. According to the invention, the method is based on mechanical synthesis, by grinding in a planetary ball mill having two identical grinding enclosures with a capacity of 150 ml each, in air, at the ambient temperature, followed by a process of finishing the perovskite phase stoichiometry by crystallization assisted by a heat treatment at a temperature in the range of 600...800°C, for 6...8 h, the method being adaptable for a broader range of perovskite materials of LaMOtype, where the cation M is a transition metal, such as Ni, Fe or Mn, with the difference that the grinding time and the post-processing temperature depend on the melting point of the precursor oxidic compound corresponding to the cation M.