The sinterability of yttrium-doped barium zirconate (BZY) has been improved through an original synthesis approach giving a core-shell type arrangement in which nanoparticulate BZY is enrobed by a thin coating of yttrium-doped barium cerate (BCY). A flash combustion route was first used to prepare BZY10 (10% yttrium-doped) in a nanopowder form with average particle diameter of 12-17 nm. The nanoparticles were then dispersed in a hydrogel generated from 3,3 0 ,3 00 -nitrilotripropionic acid complexed metal (yttrium, barium, cerium) acrylates. After thermal elimination of the organic moieties, a material of novel macroscopic architecture is obtained, which can be densified (apparent density g 97%) by sintering compacted pellets at 1300 °C for 10 h, i.e. some 200 °C lower than is generally used to densify BZY. X-ray diffraction indicates that two phases corresponding to BCY10 and BZY10 are present and that no discernible migration of atoms occurs between the zirconate core and the cerate shell. Proton conductivities of densified pellets were determined in a moist nitrogen atmosphere in the range 300-600 °C using impedance spectroscopy. The total conductivity is in the range 4.1 Â 10 -4 S/cm (300 °C)-9.5 Â 10 -3 S/cm (600 °C), which is an order of magnitude higher than that of BZY10, prepared under equivalent conditions and the core-shell material displayed improved stability against carbonate formation in a CO 2 atmosphere. The densification, proton conductivity, and CO 2 uptake properties of the novel core-shell structured proton ceramic all differ from those of yttrium-doped barium zirconate cerate solid solution containing a similar ratio of yttrium, zirconium, and cerium, and of a physical mixture of BCY10 and BZY10, and show an improved set of properties compared with those of BCY10 or BZY10 alone.
Three different routes allowing preparation of nanoparticulate yttrium-doped barium cerate have been developed: flash combustion, hydrolysis of complexed metal acrylates, and the use of inverse micelles. These methods allow preparation of doped perovskites of particle size in the range 5 - 50 nm. Water uptake characteristics have been determined after high temperature sintering, and proton conduction properties characterized between 400 and 600 {degree sign}C. The availability of sufficiently small particles opens up the possibility of using deposition techniques from colloidal suspensions of powders: In this work, nonporous BaCe0.9Y0.1O2.95 thin films have been synthesised on porous NiO/BCY10 substrates by spin coating. Scanning electron microscopy show that these films are dense, homogenous and with a thickness of 40 µm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.