The Effect of Hydrogen and Water on the Oxidation of Chromia-Forming Alloys

技术：固体氧化物燃料电池（SOFC）最有前途的金属互连材料是氧化铬形成合金。互连合金提供阳极（燃料）和阴极（空气）之间的电连接，并因此暴露于氢气和水蒸气，这通常对抗氧化性有害。虽然水通常会增加氧化速率，但它也可以通过改善氧化物垢粘附而有益。此外，对于一侧暴露于燃料而另一侧暴露于空气的金属（如在SOFC中），氢的作用进一步复杂化，其中氢可以从燃料通过合金扩散到空气侧并影响空气中的氧化。研究将侧重于表征氢对潜在互连材料的两个相互关联的性能标准的影响：抗氧化性和电阻。氧化铬的氧化行为直接取决于其输运性质，因此可以通过氧化实验间接评价其输运性质。氧化实验将补充与氧化铬的组合物和条件（如氧分压）在不断增长的规模存在的散装运输性能的表征。氢气将以不同的形式（水蒸气、氢气、溶解氢）在不同的时间引入。质子传导电解质将用于控制和监测氢分压。非技术性：从这项研究中获得的更好的理解将有助于解决固体氧化物燃料电池开发中的实际问题，以及氧化铬形成合金的其他高温应用。此外，本研究所开发的技术可应用于评估水蒸气对其他合金体系氧化行为的影响。在教育和外联方面，该项目将增加少数群体在科学和工程领域的代表性，并促进基础科学在技术发展中的重要性。PI参与了各种活动，以增加少数民族在本科和研究生阶段科学和工程专业的代表性，这两个阶段都参与了该项目。这些活动为招收少数民族学生提供了机会。虽然少数群体在研究生一级的代表性特别低，因此，在学术界，重要的是吸引少数群体学生在本科一级进行研究。少数族裔的工程专业毕业生对一些公司特别有吸引力，这是一个好迹象，表明至少有一些公司重视劳动力的多样性，但增加了招聘学生进行研究生学习的难度。让少数民族学生参与本科阶段的研究有助于吸引他们攻读研究生，并将在本项目中使用。该金属计划项目与EPSCoR共同分享50%。

TECHNICAL: The most promising metallic interconnect materials for solid oxide fuel cells (SOFCs) are chromia-forming alloys. The interconnect alloy provides electrical connection between the anode (fuel) and cathode (air) and is thus exposed to both hydrogen and water vapor, which are generally detrimental to the oxidation resistance. Although water generally increases the oxidation rate, it can also be beneficial by improving oxide scale adherence. In addition, the effect of hydrogen is further complicated for a metal exposed to fuel on one side and air on the other side (as in a SOFC), where hydrogen can diffuse from the fuel through the alloy to the air side and affect the oxidation in air. Research will focus on characterization of the effect of hydrogen on two interrelated performance criteria for potential interconnect materials: oxidation resistance and electrical resistance. The oxidation behavior depends directly on the transport properties of chromia, so the transport properties are evaluated indirectly through oxidation experiments. Oxidation experiments will be complemented with characterization of the bulk transport properties of chromia in compositions and conditions (e.g. oxygen partial pressure) present in a growing scale. Hydrogen will be introduced in different forms (water vapor, hydrogen gas, dissolved hydrogen) and at different times. Proton-conducting electrolytes will be used to control and monitor the hydrogen partial pressures. NON-TECHNICAL: The improved understanding of gained from this research would help address practical problems in the development of solid oxide fuel cells, as well as in other high-temperature applications of chromia-forming alloys. In addition, the techniques developed in this research could be applied to the evaluation of the effects of water vapor on the oxidation behavior of other alloy systems. In terms of education and outreach, the project would increase the representation of minorities in science and engineering and promote the importance of basic science in technological developments. The PI is involved in a variety of activities for increasing the representation of minorities in science and engineering at the undergraduate and graduate levels, both of which are involved in this project. These activities provide opportunities for recruitment of minority students. Although, minorities are particularly underrepresented at the graduate level and, as a result, in academia, it is important to attract minority students to research at the undergraduate level. Minority engineering graduates are particular attractive to some companies, which is a good sign that at least some companies are placing value on diversity in the workforce, but increases the difficulty in recruiting the students for graduate studies. Engaging minority students in research at the undergraduate level helps to attract them to graduate studies and will be used in this project. This Metals Program project is being co-shared at 50% level with EPSCoR.