DESC0023906

In order to move toward a future of cleaner and renewable energy, the hydrogen turbine industry is looking to increase its operations to 100% hydrogen. Due to the demand to improve energy efficiencies, higher temperatures and more corrosive environments will be created in the process for the internal turbine’s component materials. These materials, such as high strength steels, single crystal alloys, Ni-based superalloys, and composite fiber reinforced materials (ceramic matrix composites or CMCs), will be subjected to temperature extremes, thermal fatigue, and highly corrosive environments. The demand for materials that can withstand these extremes and maintain their structural integrity and reusability is crucial for the hydrogen turbine industry. With the combustion chamber having the highest temperatures, materials for gas turbine combustion parts must possess oxidation resistance, high creep rupture strength, and resistance from cycling fatigue. CMCs are typically employed for these parts but are not as capable of withstanding the thermal loading and highly reactive environment caused by high temperature oxidation and steam production. Environmental and thermal barrier coatings (EBCs and TBCs) are designed to mitigate these issues by providing a barrier between the underlying material and external environment. However, current material coatings for CMC components do not hold all the necessary properties for TBC/EBC functionality and fall short with thermal expansion coefficient mismatch to the underlying component, as well as thermo-mechanical fatigue, creating additional obstacles. Therefore, identifying materials that can provide the necessary thermal and environmental protection and possess appropriate chemical compatibility to combustion material components is the ultimate challenge. The main objectives of this work are to design, synthesize, and develop novel multicomponent ceramics that possess enhanced thermal and oxidative resistant properties for the higher temperatures and extreme environments found in hydrogen gas turbine engines and allow for TBC/EBC implementation on SiC/SiC CMC gas turbine components. To achieve these goals, MillenniTEK’s intentions are to identify less explored single component ceramic structures that already possess advantageous material properties, apply the multicomponent principle to a single atomic site (3 or more cations), and study the thermal, mechanical, and corrosion resistant properties. In this effort, traditional solid-state reactions will be used for the synthesis, however wet chemistry methods may also be employed to improve the powders for coating processing and final microstructural effects. The most promising compositions will be selected for thermal spray coating onto SiC/SiC substrates for further viability testing. Thermal conductivity, linear thermal coefficient of expansion, tensile adhesion testing, water vapor corrosion resistance, and thermo-mechanical testing will be conducted to determine feasibility and viability of these potential TBC/EBCs. These results will be compared to the single component ceramics and current commercially used coatings. Additional characterization will include scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS) to analyze and characterize the microstructures for the spray plasma coated specimens before and after thermal and environmental testing, and to verify elemental composition and homogeneity. In addition to the hydrogen turbine industry, there are other areas that could benefit from this technology where the need for manufacturing of materials for high temperature, corrosion resistant, structural applications are required, including aerospace and defense, automotive, construction, and propulsion.