Title: Friction and wear behaviour of HVOF sprayed Cr₂O₃-TiO₂ coatings on aluminium alloy

Authors: G.S. Pradeep Kumar; R. Keshavamurthy; M. Prabhu Akhil; K. Kiran; Mervin J. Thomas; Vijay Tambrallimath; Gurumoorthy S. Hebbar

Addresses: Department of Mechanical and Automobile Engineering, CHRIST (Deemed to be University), Bangalore, India ' Department of Mechanical Engineering, Dayananda Sagar College of Engineering, Bangalore, India ' Department of Mechanical and Automobile Engineering, CHRIST (Deemed to be University), Bangalore, India ' Department of Mechanical and Automobile Engineering, CHRIST (Deemed to be University), Bangalore, India ' Department of Mechanical and Automobile Engineering, CHRIST (Deemed to be University), Bangalore, India ' Department of Automobile Engineering, Dayananda Sagar College of Engineering, Bangalore, India ' Department of Mechanical and Automobile Engineering, CHRIST (Deemed to be University), Bangalore, India

Abstract: This study investigates the tribological behaviour of Cr₂O₃-TiO₂ composite coatings deposited on aluminium 6061 alloy. Cr₂O₃-TiO₂ composite coatings were deposited by high velocity oxyfuel (HVOF) technique. Developed coatings were subjected to microstructure studies, microhardness test (ASTM E92), friction and wear test (ASTM G99). Pin-on-disc machine was used to evaluate friction and wear characteristics of Cr₂O₃-TiO₂ coatings. Effect of sliding velocity (0.314 m/s-1.26 m/s) and load (20 N-100 N) on friction and wear characteristics of Cr₂O₃-TiO₂ coatings were studied and compared with uncoated aluminium alloy. Results showed 54% improvement in hardness of Cr₂O₃-TiO₂ coatings in comparison with aluminium alloy. Coefficient of friction and wear rate decreases by 12% and 48% respectively when evaluated with uncoated aluminium alloy. Coefficient of friction (COF) and wear rate increases with increase in load and sliding velocity for both coatings and substrate. However, Cr₂O₃-TiO₂ coatings showed lower wear rate and COF at all the loads and sliding velocities studied when compared with uncoated aluminium alloy. Worn out surfaces of uncoated and Cr₂O₃-TiO₂ coated surfaces were subjected to SEM analysis to understand the wear mechanisms in composite coatings.

Keywords: HVOF coatings; Cr₂O₃; TiO₂; Al6061 alloy; friction; wear; hardness.

DOI: 10.1504/IJMATEI.2021.113213

International Journal of Materials Engineering Innovation, 2021 Vol.12 No.1, pp.1 - 17

Received: 04 May 2020
Accepted: 21 Jun 2020
Published online: 24 Feb 2021 *

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