KINETIC-STUDY OF LA2CUO4 FORMATION FROM AN OXALATE PRECURSOR

The formation kinetics of La2CuO4 obtained from an oxalate precursor was studied. The as-coprecipitated oxalate is a mixture of both metallic precursor oxalates, as determined by X-ray diffraction and thermal analysis. Both metallic oxalates preserve their independent formation kinetics for temperatures up to 700-degrees-C, where the beginning of La2CuO4 formation is observed. The lanthanum oxalate present crystallizes at almost-equal-to 350-degrees-C, transforms into oxide carbonate La2O2CO3 between 350 and 600-degrees-C, and into La2O3 at higher temperatures. The copper oxalate transforms into CuO at almost-equal-to 300-degrees-C and remains as CuO at higher temperatures. High-quality single-phase La2CuO4 is obtained by heat treating the as-coprecipitated oxalate in air at 950-degrees-C for 2 h.