Sintering and Oxidation Behaviors of LaCrO_3-Dispersed Cr Alloy for Metallic Interconnector of Solid Oxide Fuel Cell

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LaCrO3-dispersed Cr alloy for metallic interconnector in solid oxide fuel cell has been studied as a function of LaCrO3 content in the range of 5 to 25 vol.%, and the sintering and oxidation properties of these alloys were examined. The Cr alloys were prepared from Cr and LaCrO3 powders, and were sintered at 1500°C under an Ar atmosphere with 5 vol.% H2. The LaCrO3-dispersed Cr alloys showed a relative density above 95%, and their sintering densities did not depend on LaCrO3 content. The LaCrO3 particles in the sintered alloys existed in grain boundaries of Cr particles, and the size of the Cr particles increased with decreasing LaCrO3 content. This means that LaCrO3 particles prevent grain growth of Cr particle during the sintering process. The isothermal oxidation tests of the Cr alloys were carried out for 2500 hrs at 1000°C in air. The oxidation behavior obeyed a logarithmic law probably due to ion diffusion within oxide scale. All Cr alloys show good oxidation resistance as compared with pure Cr, which is considered for LaCrO3 to increase a density of oxide scale. In particular, Cr alloys with 10 to 20 wt.% LaCrO3 are very resistant to oxidation. These results indicate that the LaCrO3-dispersed Cr alloys satisfy the sintered density and oxidation resistance requirements of interconnection material in solid oxide fuel cell.
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