Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
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Densification and Electrical Conductivity of Plasma-Sprayed (Ca, Co)-Doped LaCrO3 Coating

플라즈마 스프레이 (Ca, Co)-Doped LaCrO3 코팅층의 치밀화 및 전기전도도

  • Park, Hee-Jin (Department of Materials Science and Engineering, Chungnam National University) ;
  • Baik, Kyeong-Ho (Department of Materials Science and Engineering, Chungnam National University)
  • 박희진 (충남대학교 신소재공학과) ;
  • 백경호 (충남대학교 신소재공학과)
  • Received : 2017.01.17
  • Accepted : 2017.02.09
  • Published : 2017.03.27
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Abstract

Doped-$LaCrO_3$ perovskites, because of their good electrical conductivity and thermal stability in oxidizing and/or reducing environments, are used in high temperature solid oxide fuel cells as a gas-tight and electrically conductive interconnection layer. In this study, perovskite $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC) coatings manufactured by atmospheric plasma spraying followed by heat treatment at $1200^{\circ}C$ have been investigated in terms of microstructural defects, gas tightness and electrical conductivity. The plasma-sprayed LCCC coating formed an inhomogeneous layered structure after the successive deposition of fully-melted liquid droplets and/or partially-melted droplets. Micro-sized defects including unfilled pores, intersplat pores and micro-cracks in the plasma-sprayed LCCC coating were connected together and allowed substantial amounts gas to pass through the coating. Subsequent heat treatment at $1200^{\circ}C$ formed a homogeneous granule microstructure with a small number of isolated pores, providing a substantial improvement in the gas-tightness of the LCCC coating. The electrical conductivity of the LCCC coating was consequently enhanced due to the complete elimination of inter-splat pores and micro-cracks, and reached 53 S/cm at $900^{\circ}C$.

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