Monitoring of friction node surfaces in the context of their physico-chemical interactions with lubricating media of different surface activity

The article deals with tribochemical influence of the surface activity of biosynthetic oils on the operational efficiency and reliability of lubricated friction nodes under the critical conditions. It is proved that the oil surface activity is caused by the structure and properties of their molecules and interactions with steel surfaces. Evaluating criteria of oil tribochemical activity influence on the steel surface modification has been studied. The significant influence of biooils on the steel surface nanolayer phase transformations, friction and steel wearing is claimed. It has been established that the effect of the steel crystal structure deformation and strengthening its surface depends on activity of composition of lubricant. It is proved that biooils lead to improved friction and wear indicators of lubricated samples. X-structural analysis of the steel surfaces showed that during friction the austenite is destroyed and ferrite is formed. Penetration in the lubricated steel nanolayers shows increasing the ferrite and decreasing the austenite content, that cases reducing the deformation degree of metal crystals, which leads to the strengthening of its surface under the plasticized layer and to decreasing the level of friction and wear due to the formed intersurface servitotribopolymer film, which is stable under critical friction.