Formation of SrVO3 precursors from Sr(OH)2 and VmOn (2/5 ≤ m/n ≤ 2/3) by mechanical stressing under ambient or reducing atmosphere

Mechanochemical and subsequent heating processes to produce SrVO3 are studied, starting from a mixture of Sr(OH)(2) and VmOn (2/5 less than or equal to m/n less than or equal to 2/3) by milling and heating in an ambient or reducing atmosphere. Single phase perovskite SrVO3 was obtained by firing the milled mixtures at 1300 degrees C under reducing atmosphere with four dehydration steps via two intermediates, Sr2V2O7 and Sr8V8O25. The fourth dehydration step. corresponding to transformation of Sr8V8O25 to SrVO3, appears at around 1100 degrees C by heating mixtures containing trivalent vanadium and milled in a reducing atmosphere. Dehydration of the mixtures was promoted by milling under N-2-4% H-2, due to reduction of precursors by hydrogen. The precursor from the mixture with III-V mixed-valent vanadium milled under N-2-4% H-2 is closer to the final product Sr\VO3 than any other precursors. (C) 1999 Elsevier Science B.V. All rights reserved.