Preparation and characterization of lanthanum zirconate

Lanthanum zirconate has been prepared by citrate synthesis, by coprecipitat ion and by sol id state decomposition of metal nitrate-urea mixtures. The r elative advantages of these methods with respect to surface area and reprod ucibility are investigated. The lanthanum zirconate phase is formed by the urea decomposition method without any additional heat treatment. In the cas e of the citrate and coprecipitation methods the pyrochlore phase is formed only after heating the precursor above 900 degrees C. The citrate method y ields the highest surface area, the coprecipitation method gives more repro ducible results. However, after washing with ethanol the coprecipitated sam ple has much higher surface area compared with the citrate method. (C) 1998 Kluwer Academic Publishers.