Rapid and Easy Assessment of Friction and Load-Bearing Capacity in Thin Coatings

Abstract

The present research paper aims to evaluate the tribological behavior of coatings in applications where high wear resistance and low friction are required, commonly used in refurbishment of various items of industrial equipment. Twelve tribological pairs made of six different coatings, corresponding to three different coating families, have been studied: TiSiN, Cr, and DLC (diamond-like carbon). The coatings were produced using a technique called high power impulse magnetron sputtering (HiPIMS). To perform the tribological tests, two methods were used to measure friction, namely energy dissipation in vibratory systems and sliding indentation. The first technique is based on the evaluation of free vibration movement with damping of a mass–spring system induced by a mechanical impulse where the contact between the vibrating device and the sample to be analyzed acts as an additional energy dissipation. At the same time, friction is determined through the inverse analysis by comparing the experimental vibratory movement with the analytical equation of the movement. The determination of the load-bearing capacity of the various coatings has been evaluated using sliding indentation tests against spherical bodies using a constant sliding speed and increasing normal loads. The results obtained in both tests allow to verify a relationship between the friction coefficients of the studied tribological pairs: µDLC < µTiSiN < µCr. This relationship does not occur in the case of the vibration test with the 100Cr6 counter-body.