| Abstract Scope |
Thermal barrier coatings (TBCs) are used on hot section of gas turbine engines to provide thermal insulation and to protect them from rapid degradation. The oxidation of the bond coat, the thermal mismatch stress, delamination cracking, corrosion and erosion are the main factors degradation of thermal barrier coatings. Functionally graded design of thermal barrier coatings improves thermal mismatch stress that causes delamination. In plasma-sprayed TBC system, laser glazing is promising method for solving oxidation, corrosion and erosion problems. In this study, alumina/CYSZ (ceria-yttria-stabilized zirconia) ceramic top layer was produced by air plasma spraying (APS) method with functionally graded design. Laser surface modification processing was applied by using CO2 laser to enhance surface properties of TBC. After glazing of TBC with different laser power, glazing speed and laser distance parameters, the best glazing parameters were determined by investigating microstructure, mechanical and roughness properties of ceramic top coating surface. |