Observations on the structural degradation of silver during simultaneous exposure to oxidizing and reducing environments

  • Prabhakar Singh
  • Zhenguo Yang
  • Vish Viswanathan
  • Jeff W. Stevenson
Fuel Cells: Materials, Processing And Manufacturing Technologies


The structural stability of silver (Ag) in dual atmosphere exposure conditions, which are representative of solid oxide fuel cell (SOFC) current collector and gas seals, has been examined in the 600–800 °C temperature range. Experiments conducted on Ag tubular sections exposed to flowing H2-3% H2O (inside the tube) and air (outside the tube) showed extensive porosity formation along the grain boundaries in the bulk metal. Similar tubular sections, when exposed to air only (both inside and outside the tube), showed no bulk porosity or structural changes. It is postulated that the porosity formation in the bulk metal is related to the formation of gaseous H2O bubbles due to simultaneous diffusion of hydrogen and oxygen followed by subsequent interaction resulting in the formation of steam. Thermochemical processes that are responsible for structural degradation are presented and discussed. Based on experimental observations, it is concluded that Ag metal may not provide adequate long-term structural stability under a dual-environment condition that is typical of interconnects or gas seals in intermediate temperature SOFCs.


corrosion diffusion hydrogen silver solid oxide fuel cell 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    W.A. Meulenberg, O. Teller, U. Flesch, H.P. Buchkremer, and D.J. Stover: “Improved Contacting by the Use of Silver in Solid Oxide Fuel Cells Up to an Operating Temperature of 800°C,” J. Mater. Sci. Eng., 2001, 36, pp. 3189–95.Google Scholar
  2. 2.
    Y. Harufuji: Japan Patent 06231784 (1994).Google Scholar
  3. 3.
    Y. Harufuji and S. Yoshida: Japan Patent 06084530 (1994).Google Scholar
  4. 4.
    A.V. Virkar, W.D. Prouse, P.C. Smith, and G.Y. Lin: US Patent 2002048700 (2002).Google Scholar
  5. 5.
    K.S. Weil and D.M. Paxton: “Development of An Oxidation Resistant Ceramic-to-Metal Braze for Use in YSZ-Based Electrochemical Devices,” Ceram. Eng. Sci. Proc., 2002, 23, pp. 785–92.Google Scholar
  6. 6.
    X. Xiao, C.Q. Tang, and Z.C. Xia: “Solid Oxide Fuel Cells With Different Cathode Materials,” Dianyuan Jishu, 2002, 26, pp. 128–30.Google Scholar
  7. 7.
    A.Q. Pham, B.W. Chung, and R.S. Glass: US Patent 2002127460 (2002).Google Scholar
  8. 8.
    U.D. Diekmann, H. Goebbels, and E. Sigismund: DE 2002014011 (2002).Google Scholar
  9. 9.
    R.L. Klueh and W.W. Mullins: “Some Observations on Hydrogen Embrittlement of Silver,” Trans. Met. Soc., 1968, 242, pp. 237–44.Google Scholar
  10. 10.
    G.L. Thomas: “Solubility of Hydrogen in Solid Copper, Silver, and Gold Obtained by a Rapid Quench and Extraction Technique,” Trans. AIME, 1967, 239, pp. 485–90.Google Scholar
  11. 11.
    W. Siegelin, K.H. Lieser, and H. Witte: Z. Elektrochem., 1957, 61, pp. 359–66.Google Scholar
  12. 12.
    H. Katsuta and R.B. McLellan: “Diffusivity of Hydrogen in Silver,” Scripta Metall., 1979, 13, pp. 65–66.CrossRefGoogle Scholar
  13. 13.
    W. Eichenauer, H. Kunzig, and A.Z. Pebler: Metallkde, 1958, 49, pp. 220–25.Google Scholar
  14. 14.
    W. Eichenauer and G. Muller: Z. Metallkde, 1962, 53, pp. 321–25.Google Scholar
  15. 15.
    E.M. Otto: “Equilibrium Pressure of Oxygen Over Ag-O-Ag at Various Temperatures,” J. Electrochem. Soc., 1966, 113, pp. 643–45.CrossRefGoogle Scholar
  16. 16.
    B. Chalmers, R. King, and R. Shuttleworth: Proc. R. Soc., 1948, A193, p. 465.ADSGoogle Scholar
  17. 17.
    T.C. Wei and J. Philips: Adv. Catal., 1996, 41, p. 359.CrossRefGoogle Scholar
  18. 18.
    X. Bao, G. Lehmpfuhl, G. Weinberg, R. Schlogl, and G. Ertl: J. Chem. Soc. Faraday Trans., 1992, 88, p. 865.CrossRefGoogle Scholar
  19. 19.
    E.D. Hondros and A.J.W. Moore: “Evaporation and Thermal Etching,” Acta Metall., 1960, 8, pp. 647–53.CrossRefGoogle Scholar
  20. 20.
    E. Fromm and E. Gebhardt: Gase und Kohlenstoff in Metallen, Springer-Verlag, Berlin/Heidelberg, 1976.Google Scholar

Copyright information

© ASM International 2004

Authors and Affiliations

  • Prabhakar Singh
    • 1
  • Zhenguo Yang
    • 1
  • Vish Viswanathan
    • 1
  • Jeff W. Stevenson
    • 1
  1. 1.Pacific Northwest National LaboratoryRichland

Personalised recommendations