Design and statistical analysis of plasma coatings on superalloy for gas turbine applications

Abstract

The Influence of plasma sprayed NiCr–Cr₂O₃ and Al₂O₃–40% TiO₂ (A40T) coatings on Inconel 617 are investigated at 900 and 1000 °C under mixed salt environment for gas turbine applications. The results revealed that the plasma coated alloy exhibits lower mass change than bare alloy in the Na₂SO₄ and NaCl salt mixture with and without V₂O₅. The response to the experimental analysis is statistically evaluated using 2³ factorial design. Further the exposed samples were analyzed by means of optical image, SEM, EDS and XRD results. The EDS and XRD analysis revealed that the oxides are rich in Ni and Mo on the surface of the samples. The coated samples exhibited better corrosion resistance in A40T when compared to NiCr–Cr₂O₃ coatings than bare alloy.

Keywords:

• Plasma coatings
• Inconel 617
• factorial design
• SEM/EDS
• XRD