Synthesis and electrical conductivity of mullite-type Bi 2 Al 4 O 9 and (Bi,Ca) 2 Al 4 O 9 ceramics
Journal
International Journal of Materials Research
Journal Volume
103
Journal Issue
4
Pages
456-463
Date Issued
2012
Author(s)
Abstract
Mullite-type Bi 2Al 4O 9 is a potential material for electrolytes in solid oxide fuel cells. Colloidal dispersed homogeneous mixtures of commercial, submicron Bi 2O 3, Al 2O 3 and CaCO 3 powders were used to fabricate mullite-type Bi 2Al 4O 9 and (Bi,Ca) 2Al 4O 9 by means of reaction sintering in the solid state or in liquid-phase assisted processes. The products were characterized using X-ray diffraction, scanning and transmission electron microscopy, and the sintering density was compared to two conventional sintering runs. This showed that the formation of the mullite-type Bi 2Al 4O 9 proceeds via dissolution of Al 2O 3 in Bi 2O 3 at the temperatures > 750 °C. Details on the formation mechanisms of mullite phase, electrical conductivity versus the residual γ-Bi 24Al 2O 39 phase, and effects of Ca-dopant are reported. © 2012 Carl Hanser Verlag.
Type
journal article