Author ORCID Identifier
0000-0002-2489-2379
Defense Date
2026
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Mechanical and Nuclear Engineering
First Advisor
Dr. Jessika Rojas
Abstract
Advanced materials capable of operating under intense radiation, high temperatures, and corrosive environments are essential for next-generation nuclear, aerospace, and energy systems. This study evaluates ultra-high temperature ceramics as multifunctional materials for two demanding applications, as fillers in polymer composites for radiation shielding and as corrosion-resistant candidates for molten chloride salts. Tungsten-, tantalum and hafnium-based ceramics were investigated due to their high density, boron content, thermal stability, and resilience under extreme conditions.
For shielding applications, ceramic powders were incorporated into epoxy matrices at different loadings to prepare composite materials. Their attenuation performance against gamma rays and thermal neutrons was measured using a 152Eu source and an Am-Be neutron source. Mechanical properties were determined through hardness, tensile, and compressive testing, while thermogravimetric analysis was used to assess thermal stability and oxidation behavior. Resistance to radiation-induced degradation was examined through controlled X-ray exposure followed by post-irradiation microstructural and spectroscopic characterization. Surface modification using silane coupling agents was also applied to improve filler dispersion, interfacial adhesion, and composite performance. To assess high-temperature corrosion resistance, cemented tungsten carbide was tested in molten KCl–LiCl at 500 °C using static immersion methods. Corrosion kinetics and degradation mechanisms were investigated using gravimetric analysis, electrochemical techniques, and post-exposure surface characterization, with results compared against conventional alloys.
The findings show that tungsten-rich ceramics provide superior gamma shielding, boron-rich systems enhance neutron attenuation, and cemented tungsten carbide offers strong intrinsic stability in molten chloride salts. These results establish key design principles for advanced materials in extreme-service environments.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
5-4-2026
Included in
Ceramic Materials Commons, Energy Systems Commons, Nuclear Commons, Nuclear Engineering Commons, Polymer and Organic Materials Commons, Structural Materials Commons