Synthesizing CuFe2O4 Spinel Powders by a Combustion-Like Process for Solid Oxide Fuel Cell Interconnect Coatings

Authors: S. N. Hosseini, M. H. Enayati, F. Karimzadeh, N. M. Sammes

Abstract:

The synthesis of CuFe2O4 spinel powders by an optimized combustion-like process followed by calcination is described herein. The samples were characterized using X-ray diffraction (XRD), differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), dilatometry and 4-probe DC methods. Different glycine to nitrate (G/N) ratios of 1 (fuel-deficient), 1.48 (stoichiometric) and 2 (fuel-rich) were employed. Calcining the asprepared powders at 800 and 1000°C for 5 hours showed that the G/N ratio of 2 results in the formation of the desired copper spinel single phase at both calcination temperatures. For G/N=1, formation of CuFe2O4 takes place in three steps. First, iron and copper nitrates decompose to iron oxide and pure copper. Then, copper transforms to copper oxide and finally, copper and iron oxides react with each other to form a copper ferrite spinel phase. The electrical conductivity and the coefficient of thermal expansion of the sintered pelletized samples were 2 S.cm-1 (800°C) and 11×10-6 °C-1 (25-800°C), respectively.

Keywords: SOFC interconnect coatings, Copper ferrite, Spinels, Electrical conductivity, Glycine–nitrate process.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1108054

References:

[1] P. Paknahad, M. Askari, and M. Ghorbanzadeh, “Application of sol-gel technique to synthesis of Copper-Cobalt spinel on the ferritic stainless steel used for solid oxide fuel cell interconnects”, J. Power Sources, vol. 266, pp. 79, 2014.
[2] S. Joshi, C. Silva, P. Wang, Y. Mozharivskyj, and A. Petric, “Copper- Magnesium-Manganese spinel coatings for solid oxide fuel cell interconnects”, J. Electrochem. Soc., vol. 161, pp. F233, 2014.
[3] N. Shaigan, W. Qu, D.G. Ivey, and W. CheN, “A review of recent progress in coatings, surface modifications and alloy developments for solid oxide fuel cell ferritic stainless steel interconnects”, J. Power Sources, vol. 195, pp. 1529, 2010.
[4] W. Qu, L. Jian, J.M. Hill, and D.G. Ivey, “Electrical and microstructural characterization of spinel phases as potential coatings for SOFC metallic interconnects”, J. Power Sources, vol. 153, pp. 114, 2006.
[5] D. Gingas¸ I. Mindru, L. Patron, O. Carp, D. Matei, C. Neagoe, and I. Balint, “Copper ferrite obtained by two soft chemistry routes”, J. Alloys Compd., vol. 425, pp. 357, 2006.
[6] V. Berbenni, A. Marini, C. Milanese, and G. Bruni, “Solid state synthesis of CuFe2O4 from Cu(OH)2.CuCO3– 4FeC2O4.2H2O mixtures: mechanism of reaction and thermal characterization of CuFe2O4”, J. Therm. Anal. Calorim., vol. 99, pp. 437, 2010.
[7] N. Hosseini, F. Karimzadeh, M.H. Abbasi, and G.M. Choi, “Microstructural characterization and electrical conductivity of CuxMn3- xO4 (0.9≤x≤1.3) spinels produced by optimized glycine–nitrate combustion and mechanical milling processes”, Ceram. Int., vol. 40, pp. 12219, 2014.
[8] S.C. Singhal, “High temperature solid oxide fuel cells: fundamentals, design and applications”, Elsevier, Ltd., 2003.