Preparation and Characterization of Protective LSM Coatings Produced by Atmospheric Plasma Spraying

Abstract:

Lanthanum strontium manganite oxides with perovskite structure are widely employed materials for protective coatings on chromium-contained metallic interconnectors in the intermediated temperature solid oxide fuel cells (ITSOFCs). The application of protective coatings is used to decrease the growth of chromium oxide and the evaporation of chromium trioxide and chromium hydroxide from the surfaces of metallic interconnectors. In this study, La_0.8Sr_0.2MnO_3-δ (LSM) protective coatings are produced by the promising atmospheric plasma spraying (APS) technique on the substrates of Crofer 22 H, Crofer 22 APU and SS441 ferritic steels with or without pre-oxidation treatment. The substrates with pre-oxidation treatment were heated to 800°C and dwelled for 12 hrs in air before APS coating process. The cross-sectional micrographs show that the LSM coatings produced by APS technique are quiet dense without penetrating cracks. The XRD results identify that the LSM coatings produced by APS under 50 kW torch power reveal desired perovskite structure without any X-ray detectable second phase. After 600 hrs ageing in air at 800°C, the initial and final ASR values of the coated Crofer 22 APU sample with pre-oxidation treatment are 1.350 and 1.694 mΩcm², respectively. The measured ASR increasing rate is only about 0.573 μΩcm²/hr. Thus, LSM coating prepared by APS technique can dramatically decrease the growth of chromium oxide to protect the metallic interconnector and the generation of gaseous Cr-contained species to avoid cathode poisoning at the operating temperatures of ITSOFCs.

• Periodical: Key Engineering Materials (Volumes 656-657)
• Pages: 68-73
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.656-657.68
• Online since: July 2015
• Authors: Chun Liang Chang*, Chang Sing Hwang, Chun Huang Tsai, Sheng Fu Yang, Wei Ja Shong, Te Jung Daron Huang, Zong Yang Jhuang-Shie
• Keywords: Atmospheric Plasma Spraying, Intermediate Temperature Solid Oxide Fuel Cell, Lanthanum Strontium Manganite, Protective Coating

References

[1] T. H. Etsell, and S. N. Flengas, Electrical Properties of Solid Oxide Electrolytes, Chem. Rev., 70 (1970) 339-376.

DOI: 10.1021/cr60265a003

[2] H. Inaba, and H. Tagawa, Ceria-based Solid Electrolytes, Solid State Ion., 83 (1996) 1-16.

[3] Z. Yang, K. S. Weil, D. M. Paxton, J. W. Stevenson, Selection and evaluation of heat-resistant alloys for SOFC interconnect applications, J. Electrochem. Soc., 150.

DOI: 10.1149/1.1595659

[9] (2003) A1188-A1201.

[4] G. Cabouro, G. Caboche, S. Chevalier, P. Piccardo, Opportunity of metallic interconnects for ITSOFC: Reactivity and electrical property, J. Power Sources, 156 (2006) 39-44.

DOI: 10.1016/j.jpowsour.2005.08.039

[5] J. W. Fergus, Effect of cathode and electrolyte transport properties on chromium poisoning in solid oxide fuel cells, Int. J. Hydrog. Energy, 32.

DOI: 10.1016/j.ijhydene.2006.08.005

[16] (2007) 3664-3671.

[6] E. Konysheva, H. Penkalla, E. Wessel, J. Mertens, U. Seeling, L. Singheiser, K. Hilpert, Chromium poisoning of perovskite cathodes by the ODS alloy Cr5Fe1Y2O3 and the high chromium ferritic steel Crofer22APU, J. Electrochem. Soc., 153.

DOI: 10.1149/1.2172563

[4] (2006) A765-A773.

[7] C. S. Hwang, C. H. Tsai, C. H. Lo, C. H. Sun, Plasma Sprayed Metal Supported YSZ/Ni–LSGM–LSCF ITSOFC with Nanostructured Anode, J. Power Sources, 180 (2008) 132–142.

DOI: 10.1016/j.jpowsour.2008.01.075

[8] C.H. Lo, C.H. Tsai, C.S. Hwang, Plasma-Sprayed YSZ/Ni-LSGM-LSCo Intermediate-Temperature Solid Oxide Fuel Cells, Int. J. of Appl. Ceram. Technol., 6.

DOI: 10.1111/j.1744-7402.2008.02294.x

[4] (2009) 513-524.

[9] D.P. Lim, D.S. Lim, J.S. Oh, I.W. Lyo, Influence of post-treatment on the contact resistance of plasma-sprayed La0. 8Sr0. 2MnO3 coating on SOFC metallic interconnector, Surf. Coat. Technol., 200 (2005) 1248-1251.

DOI: 10.1016/j.surfcoat.2005.08.131

[10] J. Harris, O. Kesler, Atmospheric plasma spraying low temperature cathode materials for solid oxide fuel cell, J. Thermal Spray Techol., 19 (2010) 328-335.

DOI: 10.1007/s11666-009-9441-z

[11] B. D. White, O. Kesler, L. Rose, Air plasma spray processing and electrochemcial charaterization of SOFC composite cathodes, J. Power Sources, 178 (2008) 334-343.

DOI: 10.1016/j.jpowsour.2007.11.061

[12] P. Yang, C.K. Liu, J.Y. Wu, W.J. Shong, R.Y. Lee, C.C. Sung, Effect of pre-oxidation on the microstructural and electrical properties of La0. 67Sr0. 33MnO3-δ coated ferritic stainless steels, J. Power Sources, 213 (2012) 63-68.

DOI: 10.1016/j.jpowsour.2012.03.054