The structural-energetic concept in the theory of friction and wear (synergism and self-organization)

Abstract

The absence of a fundamental approach to friction and wear does not allow for well-founded solutions to the problems of machine service life and reliability control; interdisciplinary nature of tribology is a typical example of this. To find solutions to tribology problems one needs a synthesis of knowledge of mechanics, thermodynamics, material science, physico-chemistry, technology and operation. The fundamentals of tribology lie in the structural-energetic principle (based on the theoretical physics findings on the nature of self-organization and the formation of new phases, i.e. ordered and stable dissipative structures). Dissipative structures form by kinetic phase transition occurring under the cooperative (synergetic) actions of strain, mass transfer and heating. Tribosystems are considered to be open thermodynamic systems that exchange energy and matter with the environment. In the case of friction, all of the processes result from two fundamental phenomena: activation (an increase in the free energy of materials in the tribosystems) and passivation (a decrease). A comprehensive approach is developed that allows us to use a good store of experimental and technical data (graphs, diagrams and tables) as a vast and ever-replenishing bank of tribotechnical characteristics. Possibilities are opened up for an optimal choice of materials, strengthening methods, coatings, lubricants and additives to fit the loading conditions of tribosystems for machines used for various purposes. A systematized physical methodology is presented that allows us to control friction, lubrication and wear through regulation of the activation and passivation processes in tribomaterials by design, technological and operational means. Integral self-organization indexes of tribosystem materials and invariant criteria for the evaluation of the tribosystem state are proposed.