Preparation of LiNbO3 powder from the thermal decomposition of a precursor salt obtained by an evaporative method

Abstract

The preparation of lithium niobate powder, LiNbO₃, using an organic niobium salt and lithium nitrate in a buffer solution of oxalic acid and ammonium oxalate has been investigated. After the evaporation of this starting solution a precursor is obtained, which upon heat treatment, yields LiNbO₃. A chemical formula for this precursor is proposed, based on IR and thermal analysis data. The thermal evolution of the precursor powder, to the point of the formation of the LiNbO₃ phase, was followed by means of thermal analysis, IR spectroscopy and powder X-ray diffraction (XRD). The results indicate that total crystallization occurs after a 550 °C heat treatment, showing that single-phase LiNbO₃ powder, with a crystallite mean size of 88 nm, can be prepared at low processing temperatures.