Friction and Wear Performance of HVOF-Sprayed Al 2 O 3 –CeO 2 Composite Coatings on AZ91 Alloy

Novel Al 2 O 3 –CeO 2 composite coatings were developed on AZ91 alloy using High Velocity Oxy Fuel (HVOF) deposition technique. Studying the effect of varying CeO 2 (20% & 40%) content, normal load (20 N to 100 N) and sliding velocity (0.314 m/s to 1.57 m/s) on microhardness and friction and wear behaviour are main objectives of this work. Examination of microstructure and phase analysis were investigated using optical microscope and X-ray diffraction. The dry sliding wear test was conducted on developed composite coatings as per ASTM G99 standard using pin-on-disc test rig. The composite coatings showed lamellar, compact and dense structure with less than 1% porosity. The X-ray diffraction analysis showed the presence of γ-Al 2 O 3 phase along α-Al 2 O 3 phase and CeO 2 particles. Highest microhardness value of 200 VHN was observed for Al 2 O 3 –40%CeO 2 coating, while lowest value of 80 VHN was recorded for uncoated AZ91 alloy. The coefficient of friction and wear rate was found to be lower for coatings. Further, with the increase in applied load and sliding distance all materials showed increase in wear rate, however, the composite coatings fared better than uncoated AZ91 alloy.