Comparison of slurry erosion performance of thermally sprayed coatings with the addition of TiO2 feedstock powder

The present study examines the tribological performance of Ni-20%Al2O3 and Ni-20%Cr2O3 composite coatings HVOF (High Velocity Oxy-Fuel) sprayed on pump impeller material i.e., SS-420. Also, 5% amount of TiO2 feedstock powder was mechanically blended to both Ni-Al2O3 and Ni-Cr2O3 coatings to analyze the enhancement in erosion wear resistance. The erosion wear performance was analyzed by slurry pot tester at the rotational speed of 750-1500 r.p.m. for the time period of 30-120 min. Fly ash was selected as the slurry material and fly ash concentration varied from 35 to 50% with the particle size domain of < 53 to 250 mm. Mechanical and surface characterization was also carried out to analyze various properties of composite coatings. Results show that 5% addition of TiO2 feedstock powder to Ni-20% Al2O3 and Ni-20%Cr2O3 composite coatings has significantly improved the erosion wear resistance of SS-420. From present investigation, it was also found that Ni-15%Cr2O3-5%TiO2 coating has more erosion resistance as compared to Ni-15%Al2O3-5% TiO2 coating. (C) 2021 Elsevier Ltd. All rights reserved.