Resistance of Laser-Clad Chromium–Nickel Coatings to Failure under Contact Fatigue Loading

Abstract

This paper presents the results of our study of the contact endurance of laser-clad chromium–nickel coatings of the NiCrBSi system with different contents of chromium, boron, and carbon (PG-SR2, containing 0.48% C, 14.8% Cr, 2.1% B wt %; and PG-10N-01, containing 0.92% C, 18.2% Cr, 3.3% B wt %) and with additions of carbides of titanium TiC (15 and 25 wt %) and chromium Cr₃C₂ (15 wt %) upon contact fatigue loading according to the scheme of the pulsing non-impact “sphere-to-surface” contact. It has been established that the contact endurance of chromium–nickel coatings with different chemical compositions and different dispersity of structure is determined by their ability to resist plastic deformation under the conditions of repeated elastic–plastic deformation upon the mechanical non-impact contact action. This study has shown that composite coatings can be created, which contain large (50–150 μm) particles of the strengthening phases, whose contact endurance will not be substantially inferior to the contact endurance of coatings with fine (1–10 μm) strengthening phases. An estimation of the ability of the surface of the coatings to resist the mechanical contact action was made with the use of the data on microindentation. It has been shown that the method of microindentation (single loading) can be used for determining the ability of chromium–nickel coatings to withstand repeated contact loadings.