Thermal shock resistance of functionally graded coatings obtained by plasma thermal spraying

Power increasing demand in aeronautical engines promoted the development of thermal barrier coatings (TBCs) obtained by Atmospheric Plasma Spray (APS). The spectacular growth in their applications leads to the demand of a very specific TBC. One of the specific roles that must achieve some TBCs is to withstand severe thermal shocks. Functionally Graded Coatings (FGC) can improve their lives due to the lack of interfaces between two layers with very different thermal expansion coefficient (TEC) (for example a metallic layer and a ceramic layer). Differences in TEC increase the internal stresses during the cooling of the parts. In this work thermal spray conditions hex e been improved in order to obtain Functionally Graded Coatings. Thermal Shock Resistance of these coatings has been compared with conventional's one. Thermal Spray conditions have been used in order to spray two different powders with very different melting point. In that way it is possible build up Functionally Graded Coatings with a unique spray gun. Thermal Shock Resistance of Coatings is improved due to the lack of interfaces between layers with different Thermal Expansion Coefficients unlike the conventional coatings where two layers of different materials are put together.