New Environmental-Thermal Barrier Coatings for Ultrahigh Temperature Alloys
Gas turbines produce approximately 35% of the total electricity generation in the U.S. Improving their efficiency is important for reducing energy usage and carbon emissions. Similarly, higher efficiency aviation and other industrial turbines would improve the economics and reduce greenhouse gas emissions in these sectors. Gas turbine efficiency largely depends on the gas temperature at the inlet; the higher the temperature, the higher the efficiency. Gas turbine operational temperature is currently limited by its component materials, particularly those in the path of the hot gas such as turbine blades, vanes, nozzles, and shrouds. Turbine blades experience the greatest operational burden because they must concurrently withstand the highest temperatures and stresses. Currently, turbine blades are made of single crystal nickel (Ni)- or cobalt (Co)-based superalloys. After many years of refinements, their development has plateaued. There is a need to discover, develop, and implement novel materials that work at temperatures significantly higher than that of the Ni or Co superalloys if further efficiency gains are to be realized.
Project Innovation + Advantages:
The University of Maryland will leverage a newly invented, ultrafast high-temperature sintering (UHS) method to perform fast exploration of new environmental-thermal barrier coatings (ETBCs) for 1300°C-capable refractory alloys for harsh turbine environments. UHS enables ultrafast synthesis of high-melting oxide coatings, including multilayers, in less than a minute, enabling rapid evaluation of novel coating compositions. By using UHS with fast-fail tests and modeling and analytics tools, the team will be able to explore hundreds of compositions and coating architectures to design and optimize 1700°C-capable ETBCs with different layer sequences, thicknesses, porosity levels, and novel compositions. Hundreds of ETBCs will be fabricated on refractory alloy substrates and tested for thermal conductivity, thermal stability, resistance to thermal cycling, and other properties. The 1700°C-capable ETBCs on the 1300°C-capable alloys could improve the efficiency of natural gas turbines and jet engines by 7% and provide a combined primary energy saving of 18-20 quads of energy by 2050.
Combining development of new ultrahigh temperature materials with compatible coatings and manufacturing technologies has the potential to increase gas turbine efficiency up to 7%, which will significantly reduce wasted energy and carbon emissions.
Coal-fired and nuclear-powered plant electricity generation is uneconomical, unsafe, outdated, and/or contributes to significant CO2 emissions. Increasing gas turbine efficiency is critical to ensuring that plants can effectively deploy their capacity to the grid, increasing energy security.
Improving gas turbine efficiency can significantly reduce carbon emissions from air travel, which represents 2% of all global carbon emissions.
By 2050, a 7% efficiency improvement in the natural gas turbines used for U.S. electricity generation could save up to 15-16 quads of energy; in civilian aircraft turbines, 3-4 quads of energy could be saved for U.S. air travel.