Co-Mn-Co复合涂层沉积过程及其高温氧化导电性能研究

The High Temperature Oxidation Behaviors and Electrical Properties of Co-Mn-Co Multilayers Prepared by Electrodeposition

摘要:

在固体氧化物燃料电池（SOFC）工作温度下，金属连接体氧化生成的铬化物易挥发，导致电池“阴极毒化”问题。为了有效抑制铬化物的挥发，钴锰尖晶石涂层作为最有前途的SOFC连接体涂层，具有良好的高温导电性能、抗氧化性能及与电池其它组件相匹的配热膨胀系数（CTE）。为研究金属Co和Mn离子在水溶液中的电沉积工艺，选择在430 SS金属连接体上制备Co-Mn-Co复合涂层和Co-Mn复合涂层，然后在750 ℃高温下热生长得到复合尖晶石涂层。同时，对500 h后生成的尖晶石氧化物涂层的表截面形貌、组织结构及高温抗氧化性和导电性能进行研究。结果表明，Co-Mn-Co结构涂层的性能优于Co-Mn双沉积结构涂层，多层复合涂层利于涂层内Co和Mn元素的互扩散，促进Co和Mn氧化物向MnCo₂O₄尖晶石的转换，从而提高涂层的高温抗氧化与导电性能。

Abstract:

At the operating temperature of a solid oxide fuel cell （SOFC）， the Cr compounds generated by the oxidation of metal connectors are volatile， resulting in "cathode poisoning" of the battery. Cobalt-manganese spinel coating is the most promising surface coating for metal interconnectors due to its good conductivity at high temperatures， oxidation resistance and thermal expansion coefficient （CTE） matching other battery components， as well as its ability to effectively inhibit the outward diffusion Cr. The electrodeposition of Co and Mn ions in aqueous solution was studied. Co-Mn composite coatings and Co-Mn-Co composite coatings were prepared on a 430 SS substrate and were oxidized at 750 °C in air for 500 h. The surface and cross-section morphology， component analysis and high temperature oxidation performance were studied. It is found that the high temperature performance of Co-Mn-Co multi-layers is better than that of Co-Mn di-layer. The structure of multi-layers promotes the formation of MnCo₂O₄ spinel and improves the conductivity and oxidation resistance of the coating at high temperatures.