PREPARATION AND CHARACTERIZATION OF LANBO4 FROM AMORPHOUS PRECURSORS

Amorphous precursors of LaNbO4 have been prepared by coprecipitation a nd mechanical alloying. Powder characteristics before and after calcin ation were studied by thermogravimetric analysis, differential thermal analysis, Fourier transform-infrared spectroscopy and X-ray diffracti on, and the crystallographic changes during thermal treatment were doc umented by high-temperature X-ray diffraction. The tetragonal structur e was stabilized at room temperature for the mechanically alloyed prod uct; cells dimensions were determined from the X-ray diffraction patte rns and volume change between monoclinic and tetragonal phase was eval uated and is discussed.