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Title: Calculation of contact angles at triple phase boundary in solid oxide fuel cell anode using the level set method

A level set method is applied to characterize the three dimensional structures of nickel, yttria stabilized zirconia and pore phases in solid oxide fuel cell anode reconstructed by focused ion beam-scanning electron microscope. A numerical algorithm is developed to evaluate the contact angles at the triple phase boundary based on interfacial normal vectors which can be calculated from the signed distance functions defined for each of the three phases. Furthermore, surface tension force is estimated from the contact angles by assuming the interfacial force balance at the triple phase boundary. The average contact angle values of nickel, yttria stabilized zirconia and pore are found to be 143°–156°, 83°–138° and 82°–123°, respectively. The mean contact angles remained nearly unchanged after 100 hour operation. However, the contact angles just after reduction are different for the cells with different sintering temperatures. In addition, standard deviations of the contact angles are very large especially for yttria stabilized zirconia and pore phases. The calculated surface tension forces from mean contact angles were close to the experimental values found in the literature. Slight increase of surface tensions of nickel/pore and nickel/yttria stabilized zirconia were observed after operation. Present data are expected to be used not onlymore » for the understanding of the degradation mechanism, but also for the quantitative prediction of the microstructural temporal evolution of solid oxide fuel cell anode. - Highlights: • A level set method is applied to characterize the 3D structures of SOFC anode. • A numerical algorithm is developed to evaluate the contact angles at the TPB. • Surface tension force is estimated from the contact angles. • The average contact angle values are found to be 143o-156o, 83o-138o and 82o-123o. • Present data are expected to understand degradation and predict evolution of SOFC.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [1] ;  [2] ;  [1] ;  [4] ;  [1] ;  [2]
  1. Institute of Industrial Science, The University of Tokyo (Japan)
  2. (Japan)
  3. Department of Mechanical Information Science and Technology, Kyushu Institute of Technology (Japan)
  4. College of Industrial Technology, Nihon University (Japan)
Publication Date:
OSTI Identifier:
22403565
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 96; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALGORITHMS; ANODES; ION BEAMS; MICROSTRUCTURE; NICKEL; SCANNING ELECTRON MICROSCOPY; SINTERING; SOLID OXIDE FUEL CELLS; SURFACE TENSION; THREE-DIMENSIONAL LATTICES; YTTRIUM OXIDES; ZIRCONIUM OXIDES