The polarity of metallic surfaces in the context of the corrosive and scuffing wear control

The concept of the metallic surfaces polarity in the context of scuffing performance is postulated and elucidated in the presented paper. The machining by grinding and surface treatment by burnishing is applied to control introducing changes in surface polarity and acid/base component of surface free energy is used for their quantitative determination. A clear relationship between the acid/base component of surface free energy and an activation of scuffing for the steel-cast iron friction pairs lubricated by oils with the surface-active sulphur-based additives is found. Obtained results are commented and clarified; thanks to the negative-ion concept of extreme pressure action of organo-sulphur compounds. Additionally, surface reactivity investigations are performed in order to determine the influence of acid/base component of surface free energy on the corrosion wear. It recognised a clear relationship between the acid/base component of surface free energy and the mass decrement of steel surfaces in the hydrochloric acid environment. On the basis of both parts of the investigations (scuffing and reactivity tests), an optimal surface polarity is determined for steel-cast iron friction pairs lubricated by lubricants with surface-active sulphur-based additives.