Synthesis and electrical conductivity of La2NiO4+δ derived from a polyaminocarboxylate complex precursor

La2NiO4+delta with a pure K-2 NiF4 phase was synthesized from a polyaminocarboxylate complex precursor with diethylenetriaminepentaacetic acid (H(5)DTPA) as ligand, and the electrical conducting properties of sintered La2NiO4+delta were investigated. The thermal decomposition of the complex precursor was investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC). Homogeneous and fine powder (100-200 nm) with a pure K2NiF4 phase was produced by calcining the complex precursor at 900 degrees C for 2 h in air. It was found that La2NiO4+delta ceramic sintered at 1300 degrees C for 4 h shows a dense microstructure with average grain size of about I mu m. The La2NiO4+delta ceramic exhibits an electrical conductivity of 76 Omega(-1) cm(-1) at 800 degrees C. This research demonstrates the advantage of the polyaminocarboxylate complex method in preparing La2NiO4+delta with respect to the simplicity of synthesis process, fine and uniform morphology of synthesized powder and superior electrical conducting properties of sintered specimen. (c) 2005 Elsevier B.V. All rights reserved.