Environmental Protection Coating System for Refractory Metal Alloys (EPCS for RMAs)

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East Hartford, Connecticut
Project Term:
04/22/2021 - 04/21/2023

Critical Need:

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 drive for higher fuel efficiency and higher core power of gas turbines used in electric power generation and aircraft propulsion requires higher peak operation temperatures in the hottest sections. Current state-of-the-art refractory metal alloys (RMAs), although highly resistant to heat and wear, tend to oxidize in the gas turbine environment. Raytheon Technologies Research Center aims to develop an environmental protection coating system (EPCS) for RMAs to radically improve long-term protection in the harsh gas turbine environment via four major technical innovations: (1) a multi-layer self-healing environmental barrier coating (EBC) that protects against the combustion gas environment, (2) an oxidation resistant diffusion barrier on the alloy surface to enhance coating stability, (3) synergistic integration of the EBC with the diffusion barrier to extend coating life, and (4) physics-based modeling to accelerate coating development and optimization.

Potential Impact:

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.


ARPA-E Program Director:
Dr. Philseok Kim
Project Contact:
Dr. Xia Tang
Press and General Inquiries Email:
Project Contact Email:


University of Wisconsin

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