Electrical characterization of La9.33Si2Ge4O26 oxyapatite for prospective intermediate-temperature solid oxide fuel cells

authors	Vitorino, N; Oliveira, FAC; Marcelo, T; Abrantes, JCC; Trindade, B
nationality	International
journal	CERAMICS INTERNATIONAL
author keywords	Apatite-type electrolyte; SOFC; Mechanical alloying; Impedance spectroscopy; Electrical properties
keywords	DOPED LANTHANUM SILICATE; APATITE-TYPE; DEFECT CHEMISTRY; ELECTROLYTES; CONDUCTIVITY; MICROSTRUCTURE; SOFC; GERMANATES; ROUTE; BULK
abstract	La9.33Si2Ge4O26 materials have been fabricated from La2O3, SiO2 and GeO2 powders by high speed mechanical alloying followed by conventional and microwave hybrid sintering at different temperatures and holding times. XRD data showed that the apatite phase is formed after 1 h of mechanical alloying at 850 rpm. This phase remained stable after conventional sintering in an electric furnace with density increasing as sintering temperatures and holding times were increased. However, the highest density was achieved for samples sintered in the microwave furnace (5.44 g cm(-3)), corresponding to a relative density of 98%. The electrical conductivity of the samples microwave sintered at 700 and 800 degrees C are 4.72x10(-3) and 1.93x10(-2) S.cm(-1), respectively, with a correspondent activation energy of 0.952 eV.
publisher	ELSEVIER SCI LTD
issn	0272-8842
isbn	1873-3956
year published	2017
volume	43
issue	4
beginning page	3847
ending page	3853
digital object identifier (doi)	10.1016/j.ceramint.2016.12.043
web of science category	Materials Science, Ceramics
subject category	Materials Science
unique article identifier	WOS:000393937900053