Synthesis and characterization of a nano-scaled barium cerate perovskite powder using starch as polymerization agent

Abstract

The preparation of nano-sized BaCeO3 powder using starch as a polymerizationagent is described herein. Phase evolution during the decomposition process of a (BaCe)-gelwas monitored by XRD. A phase-pure nano-sized BaCeO3 powder was obtained aftercalcining of the (BaCe)-gel at 920 °C. The resulting powder has a specific surface area of 15.4m2/g. TEM investigations reveal particles mainly in the size range of 30 to 65 nm. Theshrinkage and sintering behaviour of resulting powder compacts were studied in comparisonto a coarse-grained mixed-oxide BaCeO3 powder (SBET = 2.1 m2/g). Dilatometricmeasurements show that the beginning of shrinkage of compacts from the nano-sized powder is downshifted by 300 °C compared to mixed-oxide powder. Compacts from the nano-sizedpowder reach a relative density of 91 % after sintering at 1450 °C for 10 h.

Estudo de obtenção da membrana cerâmica densa BaCeO3

“…Segundo a literatura, é comum encontrar a presença de fases secundárias como carbonato de bário e óxido de cério quando a calcinação é realizada em temperatura inferior a 1100 °C [16]. Através do refinamento de Rietveld foi constatado que o material BaCeO 3 apresentou sistema cristalino do tipo ortorrômbico com grupo espacial Pmcn, concordante com a literatura [16][17][18][19][20][21].…”