Tribological Study of the Friction between the Same Two Materials (RAD Steel)

These demands more and more severe of the organs of friction lead to operating temperatures of more and more high which result in particular a degradation of materials. This is reflected by decreases of performance that could jeopardize the safety (fall of the coefficient of friction) and penalize the economic balance (increase the wear). Our study highlights the interactions between the thermal, tribology, and physicochemistry and has been designed to respond to the following three objectives: (1) characterize at the macrolevel the phenomena of thermal localization and identify their influence on the coefficient of friction, (2) correlate to the local scale these phenomena to the physical mechanisms of friction, and (3) to identify the consequences of the degradation of the material with the temperature, based on the coefficient of friction and the physical mechanisms of friction.

Green Tribology

This chapter provides an overview of Green tribology, which is a new direction in the development of tribology, a new interesting area for scientific researches and a new way to turn tribology into a friend of ecological environment and saving energy. Green tribology is considered as well as close area with other “green” disciplines like green engineering and green chemistry. In the chapter, the various aspects of green tribology such as the concept, perspectives, role and goal, main principles, primary areas, challenges and directions of the future development have been discussed. It was clarified that green tribology can be defined as an interdisciplinary field attributed to the broad induction of various concepts such as energy, materials science, green lubrication, and environmental science. The most important role and goal of green tribology is improvement of efficiency by minimizing wear and friction in tribological processes to save energy, resources and protect environment, and consequently, improve the quality of human life. The twelve principles and three areas of green tribology were analyzed. Observation of these principles can greatly reduce the environmental impact of tribological processes, assist economic development and, as a result, improve the quality of life. The integration of these areas remains the major challenge of green tribology and defines the future directions of research in this field. This work also presents a rather detailed analysis of the most important effect in green tribology—the “zero-wear” effect (selective transfer effect). It was established that the “zero-wear” effect is due to self-organization in frictional interaction in tribological systems, which is the consequence of the complex tribo-chemical reactions and physico-chemical processes occurred in the area of frictional contact, that lead to the manifestation of unique tribological characteristics: super-antifrictional (friction coefficient ~ 10−3) and without wear (intensity wear ~10−15). This condition of tribo-system was provided by a protective nanocrystalline servovite film made of soft metal with unusual combination of mechanical properties.