Gas Phase Combustion Synthesis of Nanopowders, Modeling and Processing Duplex Microstructures

纳米粉末的气相燃烧合成、双相微结构的建模和加工

• 批准号: 1105361
• 负责人: Richard Laine
• 金额: $ 78万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1105361&HistoricalAwards=false
• 关键词: Gas; Phase; Combustion; Synthesis; Nanopowders

NON-TECHNICAL DESCRIPTION: Metal oxide nanopowders play major roles in applications including recording media, catalysts, as fillers for plastics, or for forming ceramic prosthetics (hip replacements). Most commercial nanopowders are made by flame processing volatile, toxic and polluting metal chlorides. Researchers at the University of Michigan (UM) have developed a process that escapes metal chlorides furnishing the same products while greatly expanding the number and types of oxides accessible. This approach has generated metal oxide nanopowders that offer novel lasing behavior; act as new catalysts for auto and diesel exhaust cleanup as well as providing facile routes to prosthetic ceramics with exceptional control of final properties. The UM process uses turbulent flames to combust metal-organic complexes (not chlorides) dissolved in alcohols. Despite the unique materials made, the exact process(es) whereby combustion generates metal ions that condense to form nuclei, which coalesce to form particles primarily of kinetic products are unknown. Given the considerable potential of this process for creating novel nanomaterials, researchers at UM are conducting basic studies including computer modeling to delineate the steps involved in particle formation to identify the scientific principles whereby nanopowders form. These principles will then be used to design the synthesis of new nanopowders for applications including catalysts, ceramic materials with controlled/novel properties including for example transparent ceramics or lithium battery electrolytes.TECHNICAL DETAILS: Liquid feed flame spray pyrolysis (LF-FSP), as developed at UM, provides a wide variety of single and mixed-metal oxide nanopowders that are often kinetic rather than the thermodynamic phases observed in most other nanoparticle syntheses. They have been shown to exhibit unique catalytic, photonic, electronic and ion conducting properties. LF-FSP uses a turbulent rather than a laminar flow flame. While laminar flow flames are easily modeled, turbulent flames are much less so. Consequently, most of the UM discoveries arise from empirical efforts. Researchers at UM believe that establishing a detailed understanding of the scientific underpinnings to LF-FSP processing will provide the basis for greatly expanding its utility in providing new nanopowders with novel properties especially for catalysts, photonic materials and in low temperature processing of dense, ceramic materials. The Laine and Violi groups have teamed together to develop a predictive model that identifies how specific processing parameters (e.g., temperature) contribute to the size and chemical composition of nanopowders. The model development is being guided and validated by the experimental techniques. In particular, they will explore the formation of spinel phase materials MOAl2O3 (M = Mg, Co, Ni, etc.) at compositions outside thermodynamic phase fields. The process variables that control the formation of these nanopowders are being assessed incisively to establish processing-property relationships of use in the modeling studies. The expected outcome entails controlled approaches to novel nanopowders for multiple practical applications. Research done in both groups is being used to train graduate and undergraduate students in the design, synthesis, characterization and processing (and handling) of nanopowders. At the undergraduate level, students from the undergraduate research opportunity program (UROP) are working with graduate students to learn how to characterize nanopowders using multiple spectroscopic tools, to map properties and to use the characterization data to develop theoretical models of the formation processes and methods of controlling what materials/nanopowders form.

非技术描述：金属氧化物纳米粉末在记录介质、催化剂、塑料填料或陶瓷假体（髋关节置换）等应用中发挥着重要作用。大多数商业纳米粉末是通过火焰加工挥发性、有毒和污染性金属氯化物制成的。密歇根大学（UM）的研究人员开发了一种工艺，该工艺可以避免金属氯化物提供相同的产品，同时大大扩展了氧化物的数量和类型。这种方法产生了金属氧化物纳米粉末，提供了新颖的激光行为;作为汽车和柴油机尾气净化的新催化剂，以及为最终性能具有特殊控制的假体陶瓷提供了简便的途径。 UM工艺使用湍流火焰燃烧溶解在醇中的金属有机络合物（而不是氯化物）。尽管制造了独特的材料，但燃烧产生金属离子的确切过程是未知的，金属离子凝结形成核，核聚结形成主要是动力学产物的颗粒。鉴于这一过程在创造新型纳米材料方面的巨大潜力，UM的研究人员正在进行基础研究，包括计算机建模，以描述颗粒形成所涉及的步骤，以确定纳米粉末形成的科学原理。然后，这些原理将用于设计新纳米粉末的合成，这些纳米粉末用于催化剂、具有可控/新颖性能的陶瓷材料（例如透明陶瓷或锂电池电解质）等应用。技术参数：在UM开发的液体进料火焰喷雾热解（LF-FSP），提供了各种各样的单一和混合金属氧化物纳米粉末，这些粉末通常是动力学相，而不是在大多数其他纳米颗粒合成中观察到的热力学相。它们已被证明具有独特的催化，光子，电子和离子传导性能。LF-FSP使用湍流火焰而不是层流火焰。虽然层流火焰很容易建模，但湍流火焰却不那么容易建模。因此，大多数UM发现来自经验的努力。UM的研究人员认为，建立对LF-FSP加工的科学基础的详细了解将为大大扩展其在提供具有新特性的新纳米粉末方面的实用性提供基础，特别是用于催化剂，光子材料和致密陶瓷材料的低温加工。Laine和Violi团队合作开发了一个预测模型，该模型可以识别特定的加工参数（例如，温度）有助于纳米粉末的尺寸和化学组成。模型的发展正在指导和验证的实验技术。特别是，他们将探索尖晶石相材料MOAl 2 O3（M = Mg，Co，Ni等）的形成。在热力学相场之外的组成。控制这些纳米粉末形成的工艺变量正在进行深入评估，以建立建模研究中使用的工艺-性能关系。预期的结果需要控制的方法，以新颖的纳米粉末的多种实际应用。 在这两个小组所做的研究正在被用来培训研究生和本科生在设计，合成，表征和加工（和处理）的纳米粉末。在本科阶段，来自本科生研究机会计划（UROP）的学生正在与研究生合作，学习如何使用多种光谱工具表征纳米粉末，绘制属性并使用表征数据开发形成过程的理论模型和控制材料/纳米粉末形成的方法。