The Tribological and Rheological Properties of Vegetable Lubricating Grease Modified of TiO2 Nanoparticles

Abstract

The article presents the results of tribological and rheological research of lubricating composition modified of various content of titanium dioxide. The analysis of anti-wear properties during the test for the tested lubricating composition indicates a significant change in this parameters for lubricants modified of titanium dioxide. A change of the value of evaluated tribological parameters leads to change in the structure of the composition carried out tests and a change in the effectiveness of the tribological protection of the tribosystem. The content of the thickener, base of oil and additive in the lubricant structure affects the level of the anti-wear properties, as evidenced by the results obtained during the tribological tests presented in this article. Also, the tribological tests were carried out with the T-02 four-ball machine for the base grease, i.e. without a modifying additive, and compared with the results obtained for lubricating greases modified with various amounts of titanium dioxide. The results of welding load, limiting pressure of seizure, scuffing load, limiting load of scuffing and limiting load of wear were used to evaluate the tribological properties. Based on the results of tribological tests of vegetable lubricating compositions, it was found, that the addition of titanium dioxide changed the anti-wear and anti-seizure properties of the vegetable lubricating compositions under study. The introduction of various amount of titanium dioxide caused an increase of dynamic viscosity at lower shear rates and significant changes of viscosity in the low temperatures. The introduction of modifier led to the decrease of yield point value from content value of used additive of tested lubricating compositions.