Experimental studies of tribosystems in the presence of fullerenes in a lubricant. Part 3. When changing the design parameters of tribosystems

Abstract

The paper presents the results of experimental studies and theoretical curves of changes in the volumetric wear rate and coefficient of friction when changing the design of tribosystems and the concentration of fullerene compositions in the lubricant. The design of tribosystems was assessed by two parameters: the value of the complex parameter, which characterizes the internal friction of the structure of compatible materials and the value of the friction areas and volumes of the material, which are located under the friction areas. This parameter is taken into account by the form factor of the tribosystem.
Experimentally, a linear monotonic dependence of the decrease in the volumetric wear rate by 23,0 – 29,2% is shown when using fullerene compositions of various concentrations. It was found that the dependences of the change in the coefficient of friction have a non-monotonic character and depend on the value of the complex parameter. When materials are combined in the tribosystem up to the value of the complex parameter equal to 1600, the friction coefficient decreases to 32,4%. When the values of the complex parameter exceed the value of 1600, the effect of reducing the coefficient of friction increases to 71%. It is concluded that the use of fullerene compositions will give the greatest effect for tribosystems, where compatible materials exceed the values of the complex parameter 1600. This conclusion shows the direction of the rational use of lubricants containing fullerene compositions.
The results of experimental studies and theoretical curves of the change in the volumetric wear rate and the friction coefficient with a change in the geometric dimensions of the tribosystem - the shape factor and the concentration of fullerene compositions, showed that an increase in the friction area, with the simultaneous introduction of fullerene compositions, contributes to a decrease in the wear rate by 22,8 - 28,7%.
It has been proved that a theoretically substantiated and experimentally confirmed average value of 0,75 g/kg of fullerenes + 99,25 g/kg of vegetable rapeseed high oleic oil as a solvent, with subsequent addition to the base oil, can act as a rational concentration when the design parameters of tribosystems change. The use of this conclusion will make it possible to rationally use fullerene compositions for the development of new lubricants.