How advancements in protective coatings can enhance turbine engine efficiency
October 25, 2025
The efficiency of turbine engines can be measured by the amount of work that can be extracted from the system. It is effectively the relationship between the cold air entering the system and the hot gases exiting the system. While higher internal temperatures increase turbine efficiency, material technologies limit maximum turbine inlet temperatures (TIT).
Turbine engines work on the principles of compression, combustion, and expansion. Ambient air entering the engine is compressed and heated for combustion. A high temperature difference between the air entering the combustor and the hot gases exiting the engine results in greater efficiency.
In other words, more work output can be achieved per unit of heat input at higher temperatures. The benefits of higher TIT have shifted the industry’s focus towards advanced coating materials to withstand higher temperatures.
Novel composites and superalloys can withstand extremely high temperatures
The combustion chamber is one of the hottest components on a jet engine, responsible for homogenization and expansion of the fuel-air mixture. Rolls-Royce states that a healthy engine operating at near-maximum thrust levels can generate up to 2,300 °C in the combustor. Despite creative cooling techniques used throughout the hot section, novel materials are used to prevent internal components from melting.
Combustors use multiple layers of protective ceramic insulating coatings, reducing the temperature loading by up to 300 degrees Celsius. However, individual layers of ceramic coatings are prone to degradation at temperatures exceeding 2,500 °C. Engine manufacturers are keen to develop protective coatings that can withstand even higher temperatures and can be applied in a single layer.
Poor oxidation resistance of materials poses a greater challenge
With constant exposure to air and moisture, several materials, including ceramic composites, are prone to deterioration from oxidation. During chemical degradation, metal atoms get oxidised and bond with the oxidising agent, compromising the strength and structural integrity of the material.
A research team at the University of Virginia (UVA) is developing new coatings using rare earth oxides to protect refractory metal alloys known for their poor oxidation resistance. The protective properties of these durable and heat-resistant alloys can be enhanced using natural chemical compounds.
According to Kristyn Ardrey, a PhD alumna of Opila’s lab at UV and first author of the research paper,
“By combining multiple rare earth oxides, tailoring properties to better protect the underlying substrate can be achieved with just a single layer. This allowed us to achieve better performance without complex multi-layer coatings.”
The secret of natural protective materials lies in the unique combination of elements made into a composite. Unique combinations of rare earth metals, such as yttrium, erbium, and ytterbium, are tested to achieve superior heat-resistance properties.
The researchers apply computational methods and machine learning to explore a wide range of material combinations. The coatings are applied to metal alloys using a variety of standard manufacturing techniques.
These metals, when exposed to extreme heat, showed greater resistance compared to existing materials. It is a matter of time before such protective coating materials allow future turbine engines to run at higher temperatures before components begin to fail.
