Tribo–Mechanical Properties of HVOF-Sprayed NiMoAl-Cr2AlC Composite Coatings

• Published in: Journal of thermal spray technology Vol. 29; no. 7; pp. 1763 - 1783
• Main Authors: Davis, Deepak, Singh, Sheela, Chakradhar, R. P. S., Srivastava, Meenu
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-10-2020
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Machines; Manufacturing; Materials Science; Peer Reviewed; Processes; Surfaces and Interfaces; Thin Films; Tribology; HVOF coating; NiMoAl alloy; AlC MAX phase; twist fatigue; tribology; Cr
• ISSN: 1059-9630; 1544-1016
• DOI: 10.1007/s11666-020-01069-8

The tribo-mechanical properties of NiMoAl-Cr
2
AlC MAX phase composite coatings on stainless steel substrate have been investigated. NiMoAl with different amounts of Cr
2
AlC (10, 20, 50 and 100 wt.%) were prepared by turbo-mixing and deposited by High-Velocity Oxy-Fuel (HVOF) method on stainless steel substrate. The phase composition, microstructure, chemical composition, tribological and mechanical properties of the coatings were analyzed using x-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy-Dispersive x-ray analysis (EDAX), pin-on-disk wear testing rig and nanohardness tester, respectively. The worn surfaces were analyzed by metallurgical optical microscope, FESEM and three-dimensional surface profiler to understand the wear behavior in detail. The addition of the Cr
2
AlC MAX phase in NiMoAl enhances the mechanical properties and reduces the surface roughness and porosity. NiMoAl-20 wt.% Cr
2
AlC and Cr
2
AlC coatings containing equal amounts of oxygen and carbon in the tribofilm show the low coefficient of friction (COF) and wear rate. The addition of the Cr
2
AlC MAX phase in the NiMoAl matrix up to 20 wt.% reduces the wear rate by one order of magnitude and enhances the coating life by 7000 twist fatigue cycles.