| Abstract [eng] |
Nowadays, many attempts are made to solve friction, wear and surface damages problems by introduction metallic and non-metallic nanopowders in lubricants and oils. The main objective relates with usage of magnetic nanoparticles in the friction space, possibilities to reduce friction or wear caused losses and treatment of surfaces damaged by microcracks. Moreover, the solid particles are formed during friction and wear of machine components and the studies of effects caused by solid particles increase the knowledge of the behaviour of real tribosystems. The aim of this work is objected with the preparation of oil suspensions with magnetic nanoparticles and investigation of tribological properties of produced suspensions. The preparation of rapeseed/SAE 10 mineral oil suspensions with Fe particles, produced Fe particles stabilization and size distribution of obtained particles are described in colloidal chemistry terms: by electrochemical aspects of NaBH4 and LiBEt3H, used surfactants steric stabilization factor. The transmetallization of Fe by copper was investigated as well. Cementation of Fe occurs as long as copper ions are present in the solution. The used surfactants for iron particles stabilization do not prevent the cementation reaction; they only decrease copper ions reduction reaction rate. Corrosion rates of iron particles in rapeseed and SAE 10 mineral oils were studied. It was found that corrosion rates of iron particles in oils correlate both with size distribution of iron particles and whole composition of produced suspensions. The efficiency of significant decrease of wear and friction losses of the surfaces in most cases relates both with produced Fe and Fe@Cu particles and whole composition of used suspensions, i.e., rapeseed or mineral oil + surfactant + Fe/Fe@Cu particles. |
