Fatigue resistance of PECVD coated steel alloy

The thin hard coating deposition techniques CVD and PVD have been used for a long time in industry. Such coatings prove very
effective in improving the tribological and corrosive resistant properties of the substrate. It was shown that the compressive residual stresses
are introduced on the surface layer from the PVD deposition process that helps to increase the fatigue limit of coated structural components.
The aim of this work is to evaluate the effect of a SiOx coating, deposited by means of PECVD technique, on the fatigue
resistance of a quenched and tempered alloy steel (39NiCrMo3). Rotating bending fatigue tests were carried out to assess its fatigue limit
and characterize any possible variation between the coated and the uncoated material. Fracture surface observations were made using
SEM on fracture surfaces, and scratch tests were performed on samples to assess the coating-substrate interface delamination.