Solid State Chemistry of Low and Negative Thermal Expansion Materials

低负热膨胀材料的固态化学

• 批准号: 0605671
• 负责人: Angus Wilkinson
• 金额: --
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-15 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0605671&HistoricalAwards=false
• 关键词: Solid; State; Chemistry; Low; Negative

Non-technical Abstract Most materials change their shape or size as temperature is varied. These changes are often unwanted, as they can lead to objects breaking when they are subjected to abrupt temperature changes (thermal shock), or malfunctioning if optical components, including ones found in fiber optic communications systems. To avoid problems of this type, it is necessary to use materials that show very small or no change in size/shape as the temperature varies. The current project focuses on developing materials that display negative (material shrinks on heating) and low (almost no change in size/shape on heating) thermal expansion, and enhancing our understanding of what controls their properties. Negative thermal expansion materials are of technological interest because they can be mixed with metals and other substances that show normal (positive) thermal expansion to produce composites (intimate mixtures) that do not change shape or size on heating. Undergraduates, graduate students and postdoctoral workers will be trained in a variety of materials preparation and testing methods as part of the project. A significant part of the work involves experiments at major national facilities, or is collaborative with other universities, providing opportunities for professional growth through interactions between researchers at different institutions.Technical abstract This project focuses on the preparation of new materials showing low or negative thermal expansion (NTE), and developing a deeper understanding of the factors that control their properties. This understanding will be of value in the search for new engineering materials. Undergraduates, graduate students and postdoctoral workers will be trained in a wide variety of synthetic and materials characterization techniques. Thermal expansion plays a very important role in determining if a material will be suitable for a particular application. Low or zero thermal expansion is necessary when dimensional stability is important, such as in the fabrication of precision optical devices. It is also highly beneficial in ceramics that are exposed to thermal shock, such as those used in cookware and in some engine and aerospace applications. Negative thermal expansion can be very valuable in niche applications, such as compensating for positive thermal expansion in another component. A significant part of the project either involves experiments at major national facilities or is collaborative with other universities. This provides opportunities for professional growth through interactions between researchers at different institutions.

大多数材料会随着温度的变化而改变形状或尺寸。这些变化通常是不必要的，因为当物体受到突然的温度变化（热冲击）时，它们可能导致物体破裂，或者光学元件（包括光纤通信系统中的元件）发生故障。为了避免这类问题，有必要使用随着温度变化尺寸/形状变化很小或没有变化的材料。目前的项目重点是开发负（材料在加热时收缩）和低（加热时几乎不改变尺寸/形状）热膨胀的材料，并增强我们对控制其特性的理解。负热膨胀材料是技术上的兴趣，因为它们可以与金属和其他表现出正常（正）热膨胀的物质混合，以产生复合材料（亲密混合物），在加热时不会改变形状或大小。作为项目的一部分，本科生、研究生和博士后工作者将接受各种材料制备和测试方法的培训。工作的很大一部分涉及在主要的国家设施进行实验，或与其他大学合作，通过不同机构的研究人员之间的互动提供专业成长的机会。本项目的重点是制备低热膨胀或负热膨胀（NTE）的新材料，并深入了解控制其性能的因素。这种理解将对寻找新的工程材料有价值。本科生、研究生和博士后工作者将接受各种合成和材料表征技术的培训。热膨胀在确定材料是否适合特定应用方面起着非常重要的作用。当尺寸稳定性很重要时，例如在精密光学器件的制造中，低热膨胀或零热膨胀是必要的。它在暴露于热冲击的陶瓷中也非常有益，例如在炊具和一些发动机和航空航天应用中使用的陶瓷。负热膨胀在小众应用中非常有价值，例如补偿另一个组件的正热膨胀。该项目的一个重要部分要么涉及在主要国家设施进行实验，要么与其他大学合作。这为不同机构的研究人员之间的互动提供了专业成长的机会。