Physical Aspects Of Wear Of The Piston-Ring-Cylinder Unit

The research in presented paper has shown that the physical aspects of interfacial phenomena, described by the total value of surface free energy and the values of its components, make it possible to select more suitable materials for sliding pairs. The total value of surface free energy depends on the molecular structure and the bonds characteris-tic of a given material and determines its hardness. In order to reduce friction losses in a sliding pair which is being designed, it is proposed to match such materials for the pair that the surface of one of them has a high sum of surface free energy components originating from van der Waals interactions while the other material’s surface has a possibly low value of the sum. Furthermore, proper values of the components of surface free energy ensure proper wettability with lubricating oil. Pursuing the practical goal of this research, a new piston packing ring/combustion engine PRC unit cylinder liner sliding pair was designed and made.