Slurry erosion behavior of plasma sprayed coating on turbine steel

Purpose The purpose of this paper is to study the effect of slurry erosion at different parameters on plasma sprayed Cr3C2 coated 13Cr4Ni turbine steel and compare the results of coated steel with bare steel. Design/methodology/approach Cr3C2 + 25NiCr coating was successfully developed on 13Cr4Ni turbine steel using plasma spraying method. The slurry erosion test was performed using a simulated erosion testing rig. The commercially available silica sand was used as abrasive media and the effect of concentration (ppm), average particle sizes and rotational speed on the slurry erosion behavior were studied at 300 and 900 impact angles. Developed coatings were characterized by scanning electron microscope, XRD, EDS and micro hardness tests and study of erosion wear. Findings Results revealed that three times higher hardness of coatings was obtained because of the hard phases of chromium carbide and nickel carbide, which restricted the abrasive wear in comparison to uncoated steel. Lower abrasive wear was observed at 900 impact angle coupled with lower levels of slurry concentration and rotational speed. Further, it was observed that initially cumulative mass loss rate was high which gets stabilized after the surface become smooth and on exposing for higher periods. Overall results indicated that erosive wear was reduced significantly by the application of developed coating. Originality/value The developed plasma sprayed coating is very useful to enhance the service life of turbine steel by lowering the effect of slurry erosion.