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Fabrication of 8YSZ-$Al_2O_3$ solid oxide full cell (SOFC) electrolyte by a spark plasma sintering method  

Kim Jae Kwang (Department of Ceramic Engineering, Hanyang University)
Choi Bong Geun (Department of Ceramic Engineering, Hanyang University)
Yang Jae Kyo (Department of Chemical Engineering, Hanyang University)
Choa Yong Ho (Department of Chemical Engineering, Hanyang University)
Shim Kwang Bo (Department of Ceramic Engineering, Hanyang University)
Publication Information
Journal of the Korean Crystal Growth and Crystal Technology / v.15, no.1, 2005 , pp. 16-20 More about this Journal
Abstract
In order to improve electrical conductivity and mechanical properties of 8YSZ SOFC electrolyte material, we used Al₂O₃ as an additive and applied the spark plasma sintering (SPS) method. The sintered bodies were densified above 96 ％ of theoretical density at 1200℃ and possessed microstructures composed of homogeneous grains less than 1 ㎛ in size. The addition of Al₂O₃ improved fracture toughness and bending strength by inhibiting grain growth of 8YSZ and increased total ionic conductivity because grain interior conductivity appeared to remain constant and grain boundary conductivity increased. It was assumed that the dissolution of Al₂O₃ into 8YSZ which was inevitable problem at commercial sintering method was effectively prohibited by the SPS technique with a relatively low sintering temperature and the reaction between Al₂O₃ and SiO₂ present at grain boundary to produce the crystalline Al/sub 2-x/Si/sub l-y/O/sub 5/ phase, resulting in the increase of grain boundary conductivity.
Keywords
8YSZ-Al₂O₃; Grain boundary conductivity; Spark plasma sintering (SPS);
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