본 논문에서는 SOFC 금속연결재로서 Crofer22APU를 적용하고자 표면에 전도성 산화막 (La0.8Sr0.2CoO3)을 습식코팅 후, SOFC 작동환경에서 산화거동, 전기적 특성변화 및 미세구조 변화를 관찰하였다. 코팅 전 샌드블러스트 장치를 이용한 Crofer22APU 표면처리를 통하여 코팅막/금속의 접합특성을 개선시킬 수 있었으며, 320 mesh의 입자크기를 갖는 알루미나 분말을 이용하여 표면처리한 경우 접착특성이 극대화되었다. La0.8Sr0.2CoO3 코팅된 시편의 전기적 특성 평가는 4-wire 법을 이용하여 SOFC 작동환경에서 약 4,000 시간 장기성능 평가하였으며 12 mW·cm2의 낮은 면저항값을 얻을 수 있었다. 실험종료 후 미세구조 분석결과에서도 전도성 산화막(La0.8Sr0.2CoO3) 코팅이 금속의 부식으로 인한 산화층의 생성속도를 늦추고 이로 인한 금속의 전기적 특성이 감소하는 것을 방지하는데 유효함을 확인하였다.

This study reports the high-temperature oxidation kinetics, ASR(area specific resistance), and interfacial microstructure of metallic interconnects coated with conductive oxides in oxidation atmosphere at 800 ℃. The conductive material LSC(La0.8Sr0.2CoO3, prepared by Solid State Reaction) was coated on the Crofer22APU. The contact behavior of coating layer/metal substrate was increased by sandblast. The electrical conductivity of the LSC coated Crpfer22APU was measured by a DC two probe four wire method for 4000hr, in air at 800 ℃. Microstructure and composition of the coated layer interface were investigated by SEM/EDS. These results show that a coated LSC layer prevents the formation and growth of oxide scale such as Cr2O3 and enhances the long-term stability and electrical performance of metallic interconnects for SOFCs.

SOFC Metallic Interconnect Protective Coating Lanthanum Strontium Cobalt Oxide

Lashtabeg A, Skinner SJ, J. Mater. Chem., 16, 3161 (2006)
Yakabe H, Hishinuma M, Uratani M, Matsuzaki Y, Yasuda I, J. Power Sources, 86(1-2), 423 (2000)
Zhu WZ, Deevi SC, Mat. Sci. and Eng., A348, 227 (2003)
Schafer W, Koch A, Herold-Schmidt U, Stolten D, Solid State Ionics, 1235 (1996)
Koch S, Hendriksen PV, Solid State Ion., 168(1-2), 1 (2004)
Zhu WZ, Deevi SC, Mat. Res. Bull, 38, 957 (2003)
Kim JH, Song RH, Hyun SH, Solid State Ion., 174(1-4), 185 (2004)
Yang Z, Xia G, Stevenson JW, Electrochem. Solid-State Lett., 8, 168 (2005)
Yang Z, Xia GG, Maupin GD, Stevenson JW, Surf. Coat. Technol., 201, 4476 (2006)
Stoermer AO, Rupp JLM, Gauckler LJ, Solid State Ion., 177(19-25), 2075 (2006)
Zhu WZ, Deevi SC, Mat. Res. Bull, 38, 957 (2003)
Chen X, Hou PY, Jacobson CP, Visco SJ, De Jonghe LC, Solid State Ion., 176(5-6), 425 (2005)
Kim HM, Hyun SH, Kim HS, Inter. J. Hydro Energy, 33, 1758 (2008)
Yang Z, Weil KS, Paxton DM, Stevenson JW, J. Electrochem. Soc., 150, 1188 (2003)
Ebnesajjad and Sina, “Surface Treatment of Materials for Adhesion Bonding,” William Andrew Publishing (2006)
Pawlowski L, “The Science and Engineering of Thermal Spray Coatings,” John Wiley & Sons Ltd. (1995)
Snogren RC, “Handbook on Surface Preparation,” Palmerton publishing (1974)