SGER: Modified Sol-Gel Processing of Nanostructured Multifunctional Active Coatings

项目概述CTS-9731396多功能活性涂层智能材料的开发就是在这一探索性研究项目中提出的。为了在麻省理工学院和海军研究实验室的这个为期六个月的合作项目中展示多功能活性涂料的可行性和潜力，研究重点将放在混合活性涂料上，这种涂料将有助于防止环境危害，例如与火灾破坏相关的有毒烟雾。智能涂层将呈现出色的热障和催化功能的组合。为了同时实现这些目标，将探索新的材料加工，以提供定制独特微结构和成分灵活性的内在能力。PI‘s建议使用纳米结构处理来实现具有增强性能和界面稳定性的涂层。具体地说，将研究改进的溶胶-凝胶工艺在纳米结构裁剪和涂层应用中的应用。多功能涂层的设计包括保护底层结构免受高温环境影响的热障涂层，以及中和释放的有毒气体的催化活性层。采用Sol-Gel工艺将获得超细的颗粒尺寸、高的晶界体积分数和可定制的孔结构，以控制涂层的传输特性。这种先进的湿化学方法因其固有的灵活性而具有吸引力，可以定制组成均一的颗粒尺寸和孔结构，并将实现比传统的粗晶涂层具有更好的耐热性的热障涂层。通过热障涂层扩散的有毒烟雾将进一步被底层的纳米晶层催化处理。纳米材料的超高表面体积比将被用来提供独特的表面反应性和活性物种的超高分散性，以有效地催化修复有毒气体。将考察各种工艺参数，以控制相对成核和生长速度，并最大限度地减少颗粒团聚，以获得高比表面积的纳米颗粒。PI将进一步开发六铝酸钡作为碳氢化合物和一氧化碳氧化的有效催化剂。这种材料比传统的贵金属催化剂便宜得多，而且热稳定性更好。PI提出了一种创新的反向纳米乳液控制的溶胶-凝胶水解合成方法，用于低温合成超高比表面积、纳米晶掺杂的六铝酸钡，以有效地氧化碳氢化合物和CO。拟议的研究将证明，纳米晶体可以以具有受控微结构的涂层的形式进行加工，这种涂层将保留其在块状陶瓷和颗粒状陶瓷中所显示的独特的传输和催化特性。进一步研究了这些杂化涂层界面的结构、热稳定性和化学稳定性。纳米复合材料工艺已经证明了设计表面反应性和晶界结构的可能性，以机械强化和热稳定所需的微结构。

PROJECT SUMMARY CTS-9731396 The development of smart materials in the form of multifunctional active coatings is proposed in this exploratory research program. To demonstrate the feasibility and potential of multifunctional active coatings in this six-month collaborative project between Massachusetts Institute of Technology and Naval Research Laboratory, research focus will be directed towards hybrid active coatings that will serve to protect against environmental hazards, such as toxic fumes associated with fire damage. The smart coatings will present a combination of superb thermal barrier and catalytic functions. To accomplish these goals simultaneously, novel materials processing will be explored to provide intrinsic capabilities for tailoring unique microstructures and compositional flexibility. The PI's propose the use of nanostructure processing to achieve coatings with enhanced performance and interfacial stability. Specifically, modified sol-gel processing will be examined for nanostructure tailoring and coating applications. The multifunctional coatings includes the design of a thermal barrier overcoat that protects the underlying structure from a high-temperature environment, and catalytically active layers that would neutralize the toxic gases released. Sol-gel processing will be used to achieve the ultrafine grain size, high volume fraction of grain boundaries and tailored pore structures of nanostructured yttria-stabilized zircona for controlled transport characteristics through the coatings. This advanced wet chemical approach is attractive for its intrinsic flexibility in tailoring compositional homegeneity grain size and pore structure, and will enable realization of a thermal barrier coating with superior thermal resistance than the conventional coarse-grained counterpart. The toxic fumes diffused past the thermal barrier overcoat will further be catalytically treated by the underlying nanocrystalline layers. The ultrahigh surface-to-volume ratio of nanostructured materials will be exploited to provide unique surface reactivity and ultrahigh dispersion of active species for effective catalytic remediation of toxic gases. Various processing parameters will be examined to control the relative nucleation and growth rates and minimize particle agglomeration to achieve high surface area nanoparticles. The PI's will further develop barium hexaaluminate as an effective catalyst for oxidation of hydrocarbons and carbon monoxide. This material is much less expensive and more thermally stable than conventional noble metal catalysts. The PI's propose an innovative controlled sol-gel hydrolysis synthesis in reverse nanoemulsion for the low-temperature derivation of ultrahigh surface area, nanocrystalline doped barium hexaaluminate for effective oxidation of hydrocarbons and CO. The proposed research will demonstrate that nanocrystals can be processed in the form of coatings with controlled microstructures that will retain their unique transport and catalytic characteristics displayed in the respective bulk ceramic form and particulate form. It is further sought to investigate the structural, thermal and chemical stability of the interface of these hybrid coatings. Nanocomposite processing has demonstrated the possibility to engineer the surface reactivity and grain boundary structure to mechanically reinforce and thermally stabilize desirable microstructures.