Tailoring of Grain Boundary Chemistry of Alumina Ceramics for Corrosion Resistance

氧化铝陶瓷晶界化学的定制以提高耐腐蚀性

• 批准号: 9625354
• 负责人: Riccardo Levi-Setti
• 金额: $ 28.43万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9625354&HistoricalAwards=false
• 关键词: Tailoring; Grain; Boundary; Chemistry; Alumina

9625354 Levi-Setti Commercial ceramics that are presently available are generally unsuitable for highly corrosive applications because they contain corrodible glassy grain boundary phases. Such phases result from the commercial use of liquid- phase sintering additives or from poor control of powder purity and processing. In this project, we are interested particularly in alumina ceramics and their corrosion properties in hydrogen fluoride (HF) ambients, with a view to developing improved materials of construction in the fluorochemical manufacturing. Corrosion research at DuPont has led to the discovery that a small amount of MgO (0.05%), a classic solid-solution sintering aid, improves the corrosion rate of alumina in HF, even in the presence of glass-forming impurities. The atomistic mechanism by which MgO functions is not understood, mainly because its influence on other cation impurities is not known. The goal of the proposed collaboration between the University of Chicago and DuPont is to improve our understanding of the grain boundary chemistry and its effect on corrosion behavior, with a view to designing corrosion-resistant ceramics. The approach will be to develop fabrication strategies that eliminate or adjust the nature of glassy grain boundaries. The distributions of trace dopants and impurities in a number of systematically designed alumina compositions will be studied by high resolution imaging secondary ion mass spectrometry (SIMS). %%% The principal focus of this study is to correlate the grain boundary chemistry of aluminum oxide to the corrosion behavior of the bulk material. This information will aid in the design of commercial ceramic materials that are resistant to corrosion by a variety of materials. ***

9625354目前可用的Levi-Setti商用陶瓷一般不适合高度腐蚀性的应用，因为它们含有易腐蚀的玻璃晶界相。这些相是由于液态烧结添加剂的商业使用或对粉末纯度和加工控制不善造成的。在这个项目中，我们对氧化铝陶瓷及其在氟化氢(HF)气氛中的腐蚀性能特别感兴趣，以期开发用于氟化工制造的改进的建筑材料。杜邦的腐蚀研究发现，少量的氧化镁(0.05%)，一种经典的固溶体烧结助剂，即使在存在玻璃形成杂质的情况下，也能提高氧化铝在HF中的腐蚀速度。氧化镁起作用的原子机制尚不清楚，主要是因为它对其他阳离子杂质的影响尚不清楚。芝加哥大学和杜邦公司提议的合作目标是提高我们对晶界化学及其对腐蚀行为的影响的理解，以期设计出耐腐蚀的陶瓷。方法将是开发制造策略，消除或调整玻璃晶界的性质。利用高分辨率成像二次离子质谱仪(SIMS)研究了一些系统设计的氧化铝成分中痕量杂质和杂质的分布。%本研究的重点是将氧化铝的晶界化学与块体材料的腐蚀行为相关联。这些信息将有助于商业陶瓷材料的设计，这些材料可以抵抗各种材料的腐蚀。***