Slurry erosion behavior of thermally sprayed ceramic nanocomposite coatings on turbine steel

The aim of the present study is to investigate the slurry erosion behavior of nano-yttria-stabilized zirconia (YSZ) reinforced Cr3C2-25NiCr ceramic nanocomposite coatings deposited on turbine steel. The Cr3C2-25NiCr coating powder, 95% (Cr3C2-25NiCr) + 5% YSZ, and 90% (Cr3C2-25NiCr) + 10% YSZ nanocomposite coating powder deposited on CA6NM steel samples by using high-velocity oxy-fuel coating technique. L-9 orthogonal array Taguchi method was used to design the experiment. Erosion tests were performed on erosion test rig under hydro accelerated conditions at different levels of various parameters. Erosion tests and analysis of variance resulted that for coated samples, velocity is the major influencing factor followed by slurry concentration, impact angle, and particle size. Velocity was the largest contributor to the mass loss, whereas particle size has the least contribution to mass loss of the coated samples. The scanning electron microscopy analysis of eroded samples revealed that craters, micropores, platelets, plowing, spalling, and so on were responsible for the mass loss of uncoated and coated samples. The incorporation of YSZ nanoparticles decreased the porosity; erodent particles cannot penetrate more deeply inside the workpiece and resulted in less erosion. It has been resulted that 95% (Cr3C2-25NiCr) + 5% YSZ and 90% (Cr3C2-25NiCr) + 10% YSZ ceramic nanocomposite coatings exhibited better erosion resistance as compared to Cr3C2-25NiCr coatings due to high microhardness and low porosity.