Comparison of thermal insulation capability between plasma-sprayed and laser-clad thermal barrier coatings

Different Al₂O₃-13%TiO₂ thermal barrier coatings(TBCs) were fabricated including the plasma-sprayed conventional coating, nanostructured coating and laser-clad nanostructured coating.Based on the analysis of microstructures of three coatings, the thermal insulation capabilities of the different coatings were comparatively studied.The results revealed that the as-sprayed conventional coating had a typical lamellar stacking characteristic.However, the nanostructured coating showed a bimodal microstructure, which was composed of fully melted regions and partially melted regions(remained nanoparticles).The fully melted regions in the plasma-sprayed nanostructured coatings were of lamellar stacking structure, while the fully melted regions in the laser-clad nanostructured coating was composed of fine equiaxed grains.The plasma-sprayed nanostructured coating displayed the best thermal barrier effect, and the thermal barrier effect of laser-clad nanostructured coating was better than that of plasma-sprayed conventional coatings.