2. Materials and methods
2.1. Materials
The TBC system, composed of a bond
thickness) and a top coat (260725 mm thickness), was deposited on the INC 738 via APS process using Sulzer Metco AG F4-MB gun. To enhance the adhesion between the TBC coating and the sub- strate, the surface of INC 738 with the dimension of 2 cm 2 cm 1 cm was grit-blasted with alumina particles before APS. The powder used for bond coat was 22SN6883, S.N.M.I. Avignon (Ni-23C0-18Cr-6Al-1Y (wt%)) with particle size of 38– 75 mm (Fig. 1-a). The ceramic top coat was Sulzer Metco 204 NS trade mark YSZ (7 wt% Y2O3–ZrO2) with particle size of 11–125 mm (Fig. 1-b). In this study, alumina powder with particle size of 40– 100 mm (Fig. 1-c) was injected on the coating surface by a powder feeder.