Investigating the structure and thermal damage resistance of molecular precursor derived ceramics for high power laser radiometry

本研究项目的目的是对BN和C-C（即BN网络和石墨烯类链）结构域的大小和形状对用于高功率激光辐射测量的分子前驱体衍生陶瓷的热输运的影响有一个基本的了解。裂解自制？一步合成技术聚硅氧烷和聚硼硅氮烷前驱体将用于形成嵌入石墨烯样碳和BN网络的陶瓷，以增强陶瓷中的热输运。此外，分子前驱体衍生的陶瓷相将与碳纳米管功能化，以开发具有所需热学和光学特性的热吸收涂层，以抵抗高能激光束（1至10 kW）的损伤。项目成果包括：(a)以拉曼光谱、x射线光电子能谱和高分辨率透射电子显微镜相结合为特征的结构数据；(b)陶瓷的热性能（热扩散率，比热容，导热系数），通过使用基于美国材料试验协会（ASTM）标准的定制装置或通过激光闪光法进行评估；(c)陶瓷的光学吸光度和激光视觉损伤阈值；(d)描述BN和C-C畴尺寸和形状对陶瓷抗热损伤性能影响的相关关系和理论。本项目将探索单源分子前体受控热分解制备陶瓷的结构和热性能。这些陶瓷具有由纳米尺寸的碳链和氮化硼网络组成的独特结构，这是传统陶瓷加工技术无法获得的。因此，有关这些陶瓷的各种热性能的结构的新的科学数据的产生将最终导致先进的能量转换系统的发展。如果成功，该项目将影响多个领域，包括热成像设备、高能激光热探测器、能量存储设备和空间结构。此外，与堪萨斯州立大学（K-State）多个工程项目的合作将允许来自代表性不足群体的本科生参与。此外，该项目还将进一步与美国国家标准与技术研究所（NIST）的科学家开展现有合作，后者将接待学生研究人员，为他们提供有效的动手科学和技术培训。

CBET - 1335862PI: Gurpreet Singh, Kansas State UniversityThe purpose of this research project is to develop a fundamental understanding of the effect of size and shape of BN and C-C (i.e., BN networks and graphene-like chains) domains on the thermal transport in molecular precursor derived ceramics for high power laser radiometry. A one-step synthesis technique involving pyrolysis of ?home-made? polysiloxane and polyborosilazane precursors for the formation of ceramics with embedded graphene-like carbon and BN networks will be utilized for enhancing thermal transport in ceramics. Further, the molecular precursor derived ceramic phase will be functionalized with carbon nanotubes to develop thermal absorber coatings with desired thermal and optical characteristics to resist damage from high-energy laser beams (1 to 10 kW). The project deliverables include: (a) structural data as characterized by a combination of Raman spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy; (b) thermal properties (thermal diffusivity, specific heat capacity, thermal conductivity) of the ceramic as assessed by use of custom made setup based on American Society for Testing and Materials (ASTM) standards and alternatively through Laser Flash Method; (c) Optical absorbance and laser visual damage threshold of the ceramic; and (d) correlations and theory describing the effect of BN and C-C domain size and shape on the thermal damage resistance of the ceramic.This project will explore the structure and thermal properties of ceramics prepared from controlled thermal decomposition of single source molecular precursors. These ceramics have unique structure consisting of nanometer size carbon chains and boron nitride network, which cannot be obtained through conventional ceramic processing techniques. Therefore, generation of new scientific data relating the structure to various thermal properties of these ceramics will eventually result in the development of advanced energy conversion systems. If successful, this project will influence multiple areas that include thermal imaging devices, high-energy laser thermal detectors, energy storage devices, and space structures. Further, collaborations with multiple engineering programs at Kansas State University (K-State) will allow participation by undergraduates from underrepresented groups. In addition, this project will also further existing collaboration with scientists at the National Institute of Standards and Technology (NIST), who will host student researchers providing them with effective hands-on scientific and technical training.