Effect of Yttria-Stabilized Zirconia (Y2O3/ZrO2) Nanoparticles Reinforced Cr3C2-25NiCr Coatings on the Microstructural and Mechanical Properties of Turbine Steel

Abstract

Abstract The present work is mainly focused on the investigation of Cr3C2-25NiCr coatings reinforced with 5 % and 10 % of yttria-stabilized zirconia (YSZ) nanoparticles deposited on the CA6NM turbine steel by using the high-velocity oxy-fuel technique. The coatings were analyzed by scanning electron microscope (SEM)/energy-dispersive X-ray spectroscopy (EDS). The phase identification of a crystalline material was done with the X-ray diffraction (XRD) technique. The SEM/EDS analysis showed that dense and homogeneous coatings were developed by the reinforcement of YSZ nanoparticles. The peaks of XRD graphs of Cr3C2-25NiCr coating reinforced with 5 % and 10 % of YSZ nanoparticles revealed that the chromium and carbon were present as a major phase, and the presence of nickel, yttrium, and zirconium was observed as a minor phase. The porosity level decreased up to 32 % and 45 % by the addition 5 % and 10 % of YSZ nanoparticles as compared with conventional Cr3C2-25NiCr coating. The surface roughness values for coated samples were found to be 5.03, 4.89, and 4.28. The nanocomposite coatings reinforced with 10 % YSZ nanoparticles exhibited the highest microhardness value (1,251 HV). The Cr3C2-25NiCr coatings reinforced with 10 % of YSZ nanoparticles resulted in low porosity, low surface roughness, and high microhardness. During the coating process, the nanoparticles of YSZ flow into the pores and gaps that exist in the coatings and provide a better shield to the substrate material. The Cr3C2-25NiCr with 10 % of YSZ nanoparticles showed better results in terms of mechanical and microstructural properties during the investigation.