• Heitjans, Paul

Abstract

The preparation of complex oxides by a conventional ceramic route requires a number of stages, including homogenization of the powder precursors, compaction of the reactants, and finally prolonged heat treatment at considerably elevated temperatures under controlled oxygen fugacity [1]. One goal of modern materials research and development has been to identify simpler processing schemes that do not rely upon high-temperature treatments for inducing solid-state reactions [2]. In our recent work, a great effort has been directed towards the single-step mechanosynthesis of Fe 2+-containig oxides (e.g., Fe2GeO4, Fe2SiO4) [3], Fe 3+-containing spinels (Li0.5Fe2.5O4, NiFe2O4, MgFe2O4) [4-9], Al 3+-containing spinels (MgAl2O4, ZnAl2O4, NiAl2O4) [10,11], and Sn 4+-containing complex oxides of the type M2SnO4 (M = Ca, Zn) [12]. To the best of our knowledge, there are only a few reports available in the literature on the single-step synthesis of these compounds (see, e.g., Refs. [3-12] and references therein). In the present work, examples are presented of the mechanochemical reactions leading to the formation of nanocrystalline complex oxides. Mössbauer spectroscopy is employed to follow the mechanosynthesis route and to characterize the structural state of the resulting nanophases at the atomic level.

Topics

• impedance spectroscopy
• compound
• Oxygen
• ceramic
• homogenization
• Mössbauer spectroscopy