Title: Mechanical and anti-wear properties of multi-module Cr/CrN coatings

Authors: Łukasz Szparaga; Katarzyna Mydłowska; Adam Gilewicz; Jerzy Ratajski

Addresses: Department of Technology and Education, Koszalin University of Technology, ul. Śniadeckich 2, 75-453 Koszalin, Poland ' Department of Technology and Education, Koszalin University of Technology, ul. Śniadeckich 2, 75-453 Koszalin, Poland ' Department of Technology and Education, Koszalin University of Technology, ul. Śniadeckich 2, 75-453 Koszalin, Poland ' Department of Technology and Education, Koszalin University of Technology, ul. Śniadeckich 2, 75-453 Koszalin, Poland

Abstract: The objects of investigations were Cr/CrN multi-module coatings deposited using a cathodic arc evaporation method (CAPVD) on HS6-5-2C steel used as a substrates. Analysed coatings possesses seven Cr/CrN modules of fixed thickness each, with various thicknesses of Cr and CrN layers. Aiming for the evaluation of mechanical properties of tested multi-module Cr/CrN coatings, its hardness and Young's modulus were measured, on the basis of which were determined values of H/E and H³/E² ratios. Coatings wear and friction coefficients were measured in so called ball-on-disc test. The adhesion of the coatings was evaluated using scratch tester and was shown that main mechanism of adhesive damage of all tested coatings at higher loads are buckle spallations. All tested coatings are also characterised by good adhesion to the substrate, which is evidenced by the fact that cracked coating remains inside the scratch track. Basing on the analysis of obtained experimental results it was confirmed and explicitly shown that the thickness of the individual layers of Cr and CrN in the multi-module coating significantly affects its critical loads (in scratch test), fracture toughness and wear rate.

Keywords: thin hard coatings; physical vapour deposition; PVD; anti-wear coatings; multi-layer coatings; nanoindentation; adhesion; scratch test; fracture toughness; ball-on-disc test; hard chromium replacement.

DOI: 10.1504/IJSURFSE.2019.097922

International Journal of Surface Science and Engineering, 2019 Vol.13 No.1, pp.37 - 49

Received: 12 May 2018
Accepted: 14 Aug 2018
Published online: 22 Feb 2019 *

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