High Temperature Oxidation Behavior of Fe- Cr Alloys with and without Ceramic Coating

• Main Authors: Chun-Lin Chu, 朱俊霖
• Other Authors: Shyong Lee
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/51591435963473372833

博士 === 國立中央大學 === 機械工程研究所 === 97 === Ten iron-based alloys and nickel-based alloys were subjected to oxidation treatment in hot air environment for various period of time. All of them were alloys that can be applied to interconnect of solid oxide fuel cell (SOFC). The effect of La0.7Sr0.3MnO3 (LSM) coating on the oxidation behavior and electric properties of alloys were examined at fuel cell operation temperature in hot air. The LSM layer prevented oxygen react with the alloy, as a result the oxidation rate of the alloy with coated LSM are magnitude lower than those of alloy at 800℃ in air. After long-term electric resistance measurements at 800°C, ASR (area specific resistance) of the ally with coated layer is less than alloy. The reason is more Cr-Mn spinel layer formation and some divalent metal ions doped into chromium oxide. The alloy coated with LSM used for metallic interconnect is suitable for an intermediate-temperature SOFC. The alloy coated with La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) sintering, the adhesion between the LSCF layer/alloy interface is excellent. After long-term electric resistance measurement, ASR for alloy coated with LSCF was less than for alloy coated with LSM. The LSCF used for metallic interconnect protective material could increase high temperature conductivity. Sealing glass over a long period of time during operation of a solid oxide fuel cell (SOFC) would generate thermal stresses in the seal and may have adverse effects on its mechanical performance. This may lead to cracking of the seal, resulting in mixing of the fuel and the oxidant gases.