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Mechanical engineering of hafnium with metal transition multilayers

Abstract:

Mechanical and tribological evolution on 4140 steel surfaces coated with Hafnium with Metal transition Multilayers systems deposited in various bilayer periods (Λ) via magnetron sputtering has been exhaustively studied in this work. The coatings were characterized in terms of structural, chemical, morphological, mechanical and tribological properties by X-ray diffraction (XRD), X-ray photo electron spectroscopy (XPS), atomic force microscopy, scanning and transmission electron microscopy, nanoindentation, pin-on-disc and scratch tests. The failure mode mechanisms were observed via scanning electron microscopy. X-ray diffraction results showed preferential growth in the face-centered cubic (111) crystal structure for Hafnium with Metal transition Multilayers as hard coatings. The best enhancement of the mechanical behavior was obtained when the bilayer period (Λ) 15 nm (n = 80), yielding the highest hardness, highest elastic modulus, the lowest friction coefficient and the highest critical load. These results indicate enhancement of mechanical, tribological, and adhesion properties, compared to HfN/VN multilayer systems with bilayer period (Λ) of 1200 nm (n = 1). So, these multilayered are present as coatings to surface on tool machining with excellent industrial applications.