Sintering of a Fine-grained BaCeO3 Powder Obtained from a Co-precipitation Method

Abstract.

J. Mater. Sci. 45 (2010) 6521–6527. (DOI: 10.1007/s10853-010-4741-8).

The formation of BaCeO3 by a co-precipitation method is described herein. The coprecipitation route leads to an orange (BaCe)-precursor powder (1). To improve the sintering behaviour, a small amount of Ge4+ was incorporated, leading to a (BaCe0.95/Ge0.05)-precursor (2). Both precursor powders results in fine-grained preceramic powders (1A, 2A) after calcination. The shrinkage and sintering behaviour of resulting powder compacts were studied in comparison to a coarse-grained mixed-oxide BaCeO3 powder (3). Compacts of 2A reach a relative density of 90 % after sintering at 1350 °C with grain-sizes between 0.9−3.2 μm. On the other hand ceramics of 1A and 3 have, after sintering at 1500 °C (10 h), relative densities of 85 % and 76 %, respectively. Ceramic bodies of 1A consisted of phase-pure orthorhombic BaCeO3, whereas bodies of 2A show reflections of BaCeO3 and a Ba2GeO4 phase. DTA investigations of samples 1A and 2A reveal three phase transitions at 255 °C (1A) and 256 °C 2 (2A) as well as 383 °C (1A) and 380 °C (2A). A very weak one can be obtained in the range 880−910 °C.