NATO STO

The quality and condition of the surface, the chemical composition and microstructure of the material together with applied stresses and the environment conditions most significantly determine the service life and operational characteristics of structural parts. Needle bearings are highly loaded parts in assemblies with rotating elements in military vehicles and other equipment. Their corrosion and wear can cause vehicle malfunction, reduced usability of the equipment, noise, vibrations, and financial losses. One of the possible solutions to this problem is the application of functional surface layers that simultaneously increase the resistance to contact pressures, wear and corrosion of needle bearings and reduce friction, heating, vibrations and bearing noise. Functional surface layers are produced by a combination of two or more physically and metallurgical different processes in which the supporting, binding and functional part of the surface layer is created. In the proposed project, it is planned to investigate the influence of several types of functional surface layers on the exploitation characteristics of needle bearings identified as critical components in military vehicle assemblies. These layers will be produced by possible combinations of surface engineering processes such as nitriding (in gas, salt bath, plasma), oxynitriding, deposition of wear and corrosion resistant coatings (TiN, TiN/TiCN) by the physical vapour deposition (PVD) or plasma-assisted chemical vapour deposition (PACVD) technology on the surface of needle bearing rings. For comparison the exploitation characteristics of coated and uncoated needle bearings, specific monitoring procedures in a laboratory condition will be developed. These procedures include simultaneously measurements of vibrations, acoustic and thermal responses of needle bearing in different working conditions and statistical evaluation of impact of applied functional layer on needle bearing characteristics. It is expected that the wear and corrosion resistant surface layers, developed specifically for the test bearings will provide a significant extension of the service life and operational characteristics compared to those of the standard uncoated needle bearings. The functional surface layers with the best operational characteristics and their monitoring procedures will be proposed for application in military vehicles.