Synthesis and electrical conductivity of La_2NiO_(4 + delta) derived from a polyaminocarboxylate complex precursor

摘要

La_2NiO_(4 + delta) with a pure K_2MF_4 phase was synthesized from a polyaminocarboxylate complex precursor with diethylenetriaminepentaacetic acid (H_5DTPA) as ligand, and the electrical conducting properties of sintered La_2NiO_(4 + 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 K_2NiF_4 phase was produced by calcining the complex precursor at 900 deg C for 2 h in air. It was found that La_2NiO_(4 + delta) ceramic sintered at 1300 deg C for 4 h shows a dense microstmcture with average grain size of about 1 |im. The La_2NiO_(4 + delta ) ceramic exhibits an electrical conductivity of 76 OMEGA~(-1) cm~(-1) at 800 deg C. This research demonstrates the advantage of the polyaminocarboxylate complex method in preparing La_2Nio_(4 + delta) with respect to the simplicity of synthesis process, fine and uniform morphology of synthesized powder and superior electrical conducting properties of sintered specimen.