Adhesion of TiC and MoN physical vapor deposition coatings determined by innovative test methods directly on coated bearings

Methods for inspecting coating mechanical properties and adhesion on final products, considering quantitative criteria are of high importance. In this paper, relevant characteristic examples for determining the adhesion of a MoN and a TiC PVD coating deposited on steel substrate are introduced. The mechanical properties of the coatings and their steel substrates were determined via nano-indentations and a FEM supported evaluation of the obtained results. The coatings' adhesion and fatigue were quantified by inclined and perpendicular impact tests respectively, coupled with appropriate finite elements method (FEM) calculations. The inclined impact tests were conducted under lubricated conditions for avoiding abrasion caused by sliding friction on the coated surfaces. In this way, the coating fatigue failure during this test was mainly affected by the impact load, the film adhesion and the material's properties. Based on these results, the coating adhesion was estimated c onsidering the impact loads and the determined material properties.