Over the last 20 years there has been a significant development in heat protective coating technologies, which are used where the coating temperature significantly exceeds the oxidation resistance of the material.

Heat protective coatings are advanced formulations that are typically applied to the metal surfaces of gas turbine engine components. These parts operate at high temperatures and experience significant thermal stresses. The coatings serve to protect against prolonged thermal stresses by utilizing thermally insulating materials that can withstand significant temperature variations.

Thus, coatings provide higher operating temperatures while limiting thermal stresses on structural components, extending component life by reducing oxidation and thermal fatigue. In combination with active film cooling, gas turbine engine parts can operate at higher temperatures than the melting point of the metal.

Currently, 2 main classes of coatings are widely used in the world – metallic and heat-protective ceramic coatings.
Until the mid 80’s, platinum and aluminum based metallic coatings were widely used. Such metallic coatings provide excellent corrosion resistance, which was proved by numerous bench and field tests.

The platinum-aluminum coating is applied by galvanic plating. First, platinum is applied in a thin layer of 0.006 mm and then aluminum is applied by diffusion.

The second type is ceramic-based thermal protection coatings. As a rule, such coatings consist of zirconium dioxide stabilized with yttrium oxide. Such a coating allows for operating temperatures of over 1200°C..

The ceramic coating is atomized through a plasma torch at temperatures in excess of 10,000 K. The material formed has good adhesion and high curing rate, forming a monolithic coating.

The ceramic coating provides a high level of corrosion resistance, which has been confirmed by numerous operating hours of gas turbine engines.