Frictional performance is governed by the topmost surface layers and modifying physico-chemical properties of these layers is an obvious choice in trying to reduce friction losses. This can be achieved by having surface films containing sulphides, chlorides or phosphides, which are known for their ability to facilitate lubrication when used as EP and AW additives to oil. Extensive plastic deformation of near-surface regions during finishing mechanical processes is known to increase diffusion activity of the metal. Based on this, we have developed beyond the state-of-the-art technology of generating lubrication-facilitating surface films by supplying sulphur-containing compounds during the microshot peening and lapping processes capable of treating surfaces of any form. To demonstrate the feasibility of this technology, cast iron and steel surfaces were treated and tested to evaluate their tribological performance. The results show that our technology allows decreasing friction manyfold under lubricated conditions including oil starvation, increases surface hardness and allows controlling surface roughness.
