DEVELOPMENT AND CHARACTERIZATION OF EB-PVD THERMAL BARRIER COATINGS WITH DIFFERENT CERAMIC MATERIALS FOR TURBINE BLADES

Thermal barrier coatings (TBC) are expected to exhibit specific properties, including low thermal conductivity, high thermal expansion capabilities, and excellent resistance to corrosion. Presently, yttria-stabilized zirconia (YSZ) is the prevailing choice for thermal barrier coatings, owing to its low thermal conductivity (approximately 1.5 W/m.K) and superior thermal shock resistance. YSZ can effectively insulate components at temperatures of around 1400 degrees C and is also compatible with various ceramic materials, including Gd2Zr2O7, Nd2Zr2O7, Sm2Zr2O7, and La2Zr2O7. Enhancements to thermal barrier coatings offer the promise of increased efficiency in gas turbine engines, as well as the extension of the service life of high- cost materials. In pursuit of these objectives, this research initiative primarily focused on the production of diverse ceramic materials, namely 7YSZ, Gd2Zr2O7, Sm2Zr2O7, Nd2Zr2O7, and 4Gd(2)O(3) + 4Y(2)O(3)SZ coating materials, characterized by optimized production parameters. These materials were synthesized from their oxide forms utilizing the solid-state method. To facilitate the adhesion of these coatings to the CMSX-4 superalloy substrate materials, a bond coat consisting of Pt-NiAl was applied using the pack cementation and VPA (Vapor Phase Aluminizing) methods. Subsequently, the synthesized ceramic materials were deposited onto the CMSX-4 superalloy substrates through the Electron Beam-Physical Vapor Deposition (EB-PVD) technique. Comprehensive characterizations were then conducted on these coating structures. Following the coating processes, scanning electron microscopy (SEM) analysis was conducted to evaluate coating thickness and morphology. Additionally, thermal conductivity, scratch resistance, and hardness tests were performed on the samples.