Chemical compatibility of perovskite-type oxide La{sub 0.7}Ca{sub 0.3}Cr{sub 1{minus}y}Co{sub y}O{sub 3} with Y{sub 2}O{sub 3} stabilized ZrO{sub 2}

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Materials Research Bulletin

DOI:https://doi.org/10.1016/0025-5408(95)00062-3· OSTI ID:82650

Kamata, Hiroyuki; Hosaka, Akio ^[1]; Mizusaki, Junichiro ^[2]; Tagawa, Hiroaki ^[3]

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1. Ishikawajima-harima Heavy Industries Co., Ltd., Koto, Tokyo (Japan). Research Inst.
2. Tohoku Univ., Aoba, Sendai (Japan). Research Inst. for Scientific Measurements
3. Yokohama National Univ., Hodogaya, Yokohama (Japan)

In order to evaluate the compatibility between the SOFC (Solid Oxide Fuel Cells) interconnector material of the perovskite-type La{sub 0.7}Ca{sub 0.3}Cr{sub 1{minus}y}Co{sub y}O{sub 3} (y = 0.05, 0.1 and 0.2) and 8mol% Y{sub 2}O{sub 3}-ZrO{sub 2}(YSZ), two types of experiments were carried out in air. One was by the reaction of powder mixtures. The reaction products were identified by X-ray analysis after heating at 1,000--1,300 C. The other was the experiments using diffusion couples. The distribution of elements at the interface was observed by EPMA for the couples heated at 1,300 C and 1,400 C. The reaction progressed mainly by the dissolution of calcium ions from the perovskite phase into YSZ. In the perovskite phase, due to the loss of A-site Ca ion, the activity of B-site ions increased, resulting in the deposition of the spinel-type CoCr{sub 2}O{sub 4}. The excess amount of calcium ions incorporated in YSZ reacted ZrO{sub 2} to form CaZrO{sub 3}. Increase of cobalt content enlarge the reactivity of the perovskite phase with YSZ. The parabolic rate constant of the reaction, k{sub p}, was determined by the thickness of CaZrO{sub 3} at the interface of the diffusion couples. Calculated k{sub p} were 2.9 {times} 10{sup {minus}12}cm{sub 2}sec{sub {minus}1} and 2.1 {times} 10{sup {minus}11}cm{sup 2}sec{sup {minus}1} at 1,300 C and 1,400 C, respectively. For the practical application as the SOFC interconnector material, the content of cobalt as a sintering accelerator in (La,Ca) CrO{sub 3} must be controlled at low level to keep the chemical interaction to a minimum.

• OSTI ID: 82650
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 6 Vol. 30; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
40 CHEMISTRY
CALCIUM OXIDES
CHEMICAL REACTIONS
CHROMIUM OXIDES
COBALT OXIDES
COMPATIBILITY
DIFFUSION
DISSOLUTION
LANTHANUM OXIDES
PEROVSKITE
POWDERS
SOLID ELECTROLYTE FUEL CELLS
SPINELS
X-RAY SPECTROSCOPY
YTTRIUM OXIDES
ZIRCONIUM OXIDES