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

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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.