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Modification of Surface Oxide Layer of Fe‐Cr‐Al Alloy with Coating Materials for SOFC Applications
Author(s) -
Pham H.C.,
Taniguchi S.,
Inoue Y.,
Matsuda J.,
Chou J.T.,
Misu Y.,
Matsuoka K.,
Sasaki K.
Publication year - 2017
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.201600038
Subject(s) - materials science , oxide , microstructure , alloy , solid oxide fuel cell , layer (electronics) , coating , crystallite , chemical engineering , surface layer , metallurgy , composite material , chemistry , electrode , engineering , anode
Abstract We investigated the treatment of Fe‐Cr‐Al alloy for application in solid oxide fuel cells (SOFCs). The electrical resistance of the Al 2 O 3 ‐based surface oxide layer on the alloy decreased and was stable when La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF), La 0.8 Sr 0.2 MnO 3 (LSM), LaNi 0.6 Fe 0.4 O 3 (LNF), or Pr 0.8 Sr 0.2 MnO 3 (PrSM) were first coated on the alloy and heat treated at 700 °C in air. The activation energy, calculated from the resistance, also suggested that the surface oxide became more conductive with treatment. The surface oxide layer after treatment had a microstructure of columns growing outward in the same direction, containing small amounts of elements such as Sr, Ni, Fe, La, Mn, and Pr. The microstructure consists of polycrystalline γ‐Al 2 O 3 and small amounts of Al compounds with these elements. In the case of the LNF coating, the formation of NiAl 2 O 4 was observed . The enhanced electrical conductivity may have resulted from the arrangement of the columnar structure, along with the electronic conduction path generated by the reaction of γ‐Al 2 O 3 with these elements.