PREPARATION OF DOPED LANTHANUM CHROMITES NANO-POWDERS BY AQUEOUS ORGANIC-GEL METHOD

Nano-powders of doped lanthanum chromites were prepared by the aqueous organic-gel method using citric acid as a complex agent and metal nitrate as starting materials. The structure and thermal decomposition of metal carboxylate precursor gel were investigated by infrared spectroscopy and thermogravimetry. With X-ray diffraction and transmission electron microscope, the crystal structure and morphology of the particles were characterized. Results show that LaCrO_(3) powder with particle size near 50 nm can be obtained by the aqueous organicgel method when the ethylene glycol is added into the precursor solution. The ethylene glycol plays an important role in gelling process and it makes the organicgel decomposed in several steps. The results also indicate that there is a transition phase during the transforming process of gel to LaCrO_(3) powder after calcination.