摘要固体氧化物燃料电池的工作温度常常在 800℃以上，相较于其他材料金属合金 更适合作为连接板材料，尤其是铁素体不锈钢。为了提高金属连接体表面导电性能 并大幅度降低不锈钢中 Cr 的挥发，保护涂层的热膨胀系数必须与电池其他组件相 匹配，同时保护涂层与电极、密封材料也应该互相相兼容。当前，最具研究前景的 涂层为钴锰尖晶石涂层，该涂层已经实现了通过多种技术被制得，然而此项技术要 不是太过昂贵就是不能直接的应用到固体氧化物燃料电池中。79866
本文首先采用高能微弧合金化技术（high energy micro-arc alloying,HEMAA）在 430 表面制备 Co-40Mn、Co-8Mn-2La、Co-38Mn-2La 涂层，然后在 800℃空气中预 氧化 2h 使得合金涂层转化为尖晶石涂层，本文最后测试了涂层在 750℃空气中及-10% 水蒸气中的高温抗氧化性能。主要研究结果如下：
该实验涂层的最佳预氧化参数为 800℃2h，氧化温度过高会导致涂层剥落严重， 氧化时间不足会导致涂层不够致密；其次还分析了不同 Mn 比例及稀土元素 La 对 涂层预氧化结果的影响。沉积层中 Mn 含量过高会生成使得涂层抗剥落性能下降的 富锰氧化物。最后研究发现稀土元素 La 可以提高涂层的粘附力并阻止氧向基材内 扩散。
在高温性能测试研究中获得了各涂层，没有沉积层的基材的氧化速度要远远快 于表面沉积尖晶石涂层的试样，这主要归因于合金涂层在高温工作环境下吸入大量 的氧气。通过扫描电镜获得涂层的表面形貌、能谱仪确定了涂层中各成分的含量， 最终确定稀土元素 La 可以提高钴锰尖晶石涂层的抗氧化行为，延长了连接体在高 温环境下的使用寿命，使得固体氧化物燃料电池的发展应用向有利方向不断迈进。
毕业论文关键字:固体氧化物燃料电池金属连接体稀土改性尖晶石涂层
Abstract For solid oxide fuel cell working at about 800 ℃, metal alloy is selected as the connection plate material, especially the ferritic stainless steel。In order to improve the surface conductivity and significantly reduce the volatilization of Cr in stainless steel, the thermal expansion coefficient of coating must match the battery other components, and be compatible with electrodes and sealing material。At present, the most promising
coating is spinel (Co, Mn)。 The coating has been achieved through a variety of technologies , and has different thickness, composition and microstructure。
At first, this experiment utilizes high-energy micro-arc alloying technology to produce Co-40Mn, Co-8Mn-2La, Co-38Mn-2La coating in the surface of 304ss。 Then in the condition of 750℃,the coating preoxides to produce spinel coating 。At last,I studied
and the oxidation behavior of coating in the condition of air and – 10%H2O。The main results were as follows:
The best preoxidation coating parameters are for 800 ℃ for 2 h in this experiment。
High oxidation temperature can entail coating spalling。 The deficiency of oxidation time can lead to coating lack of enough density; Secondly this experiment also analyzed the different proportion of Mn and rare earth element La on the result of oxidation coating。Higher Mn concentration in the sediments can generate rich manganese oxide and make the coating spalling resistance poor。Rare earth element La can improve the adhesion of the coating performance and prevent oxygen in diffusion。
Coating is obtained in the study of high temperature performance testing。 The speed of oxidation of spinel coating is much lower than the past time。 This is mainly attributed to the alloy coating absorbing oxygen。 By scanning electron microscopy coating surface morphology, spectrometer to determine the content of each component in the coating。 At last we determine the rare earth element La can increase the oxidation behavior of manganese cobalt spinel coating and prolong the longitude of life of the connecting body under the environment of high temperature。 These make the development and application of solid oxide fuel cell stride forward in the good direction。。 稀土元素La对合金涂层结构与高温性能的影响:http://www.youerw.com/cailiao/lunwen_92579.html