Ni-YSZ cermets for solid oxide fuel cell anodes via two-step firing

authors	Davarpanah, A; Yaremchenko, AA; Fagg, DP; Frade, JR
nationality	International
journal	INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
author keywords	Ni-YSZ; Composite; Cermet; SOFC anode; Electrical conductivity; Two-step sintering
keywords	YTTRIA-STABILIZED ZIRCONIA; NICKEL-OXIDE; ELECTRICAL-PROPERTIES; NI/YSZ CERMETS; TRANSPORT-PROPERTIES; CONDUCTIVITY; COMPOSITES; ELECTROLYTE; CERAMICS; KINETICS
abstract	The electrochemical performance and dimensional stability of Ni-YSZ cermets, conventionally used as solid oxide fuel cell anodes, depend strongly on their microstructure and therefore fabrication conditions. This work was focused on the assessment of a less common two-step firing procedure for fabrication of Ni-YSZ cermets with comparatively low nickel fraction of 30 vol.%. The impact of different firing parameters including peak temperature (1623-1723 K), heating/cooling rate (4-10 K/min), and isothermal treatment temperature (1473-1573 K) and time (2-8 h), on the porosity and electrical conductivity of cermets was assessed employing Taguchi experimental planning. The applied procedure yielded Ni-YSZ composites with porosity 26-35% and electrical conductivity ranging from 170 to 420 S/cm at 873-1173 K in 10%H-2-N-2 atmosphere. Microstructural studies indicated that the conductivity is determined mainly by Ni particle size distribution. Analysis of results suggests that, for the studied range of sintering parameters, a higher peak temperature and ramp rate are favorable for the improvement of conductivity, whereas isothermal dwell temperature and time have a rather minor effect on the conductivity level. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
publisher	PERGAMON-ELSEVIER SCIENCE LTD
issn	0360-3199
year published	2014
volume	39
issue	27
beginning page	15046
ending page	15056
digital object identifier (doi)	10.1016/j.ijhydene.2014.07.053
web of science category	Chemistry, Physical; Electrochemistry; Energy & Fuels
subject category	Chemistry; Electrochemistry; Energy & Fuels
unique article identifier	WOS:000341897500059