**3.3 Challenges of green tribology**

Green tribology as a new area of tribology has a number of challenges. One obvious problem is integration, synergy of its above mentioned focus areas so that they can benefit from each other. Obviously, a lot of researches is needed to integrate the fields of green tribology. Some ideas can be borrowed from the related fields of green chemistry and green engineering, for example, the development of quantitative parameters for assessing the impact of tribological technologies on the environment. It is also important to develop quantitative measures and metrics that would allow us to compare which tribological material, technology, or application is "greener," i.e., produces lower carbon footprint, less waste from worn-out materials, and less chemical and heat pollution to the environment.

Green tribology should be integrated into world science and contribute to solving global problems such as resource depletion, environmental pollution and climate change. The application of principles of green tribology by itself, of course, will not solve world problems, and only major scientific achievements can become the key to their solution.

In the face of a large number of tribological problems requiring an early solution, which related to the environmental pollution, crisis of energy and resources on global scale, green tribology should be extended in the following directions [2].


**55**

*Green Tribology*

these materials;

of the friction pair…" [4].

essential.

*DOI: http://dx.doi.org/10.5772/intechopen.94510*

• Making the traditional tribo-materials and lubricating materials "green" in the course of a lifecycle, namely, realizing cleaner production or eco-design of the

Consequently, tribologists should devote all their efforts to the investigation, application and development of green tribology, thereby making a valuable contri-

It seems expedient, at least briefly, to consider how the achievements that were obtained in the study of self-organizing tribo-systems, and in particular, the "zerowear" (effect of wearlessness/effect of selective transfer—ST), play a role in the

The effect of ST in friction was registered as opening in 1966, with a priority in 1956. The authors of this discovery – D.N. Garkunov and I.V. Kragelsky – stated that the essence of the observed phenomenon as follows: "…that in the friction of couple copper alloys-steel under boundary lubrication, eliminating the oxidation of copper, there is a phenomenon of ST of a solid solution of copper from copper-alloy to steel and its transfer backwards from steel to copper alloy, with a reduction of the friction coefficient as liquid lubrication and leads to a significant reduction in wear

In the closing years of the XX century the "zero-wear" effect is defined as one of the examples of self-organization in frictional interaction in tribological systems [41, 42], and since then, a synergistic approach at his description has become

Classical tribo-system for realizing of ST is a system of "copper alloy (bronze or brass) – aqueous or alcoholic solution of glycerol – steel". The evolution of the tribological properties of this system visually demonstrated the self-organization in friction in ST mode, which is expressed in the ultra-low frequency vibrations of the

Self-organization in the ST mode during friction is the consequence of the complex tribo-chemical reactions and physico-chemical processes occurred in the area of frictional contact, which 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 [43]. According to the results of nanoindentation, such a film

Within the framework of the I.V. Kragelsky's molecular-mechanical theory, the providing extremely low friction coefficients and practical absence of wear during friction of solids is possible either at spontaneous generation of wear autocompensation systems or in the case of friction of perfectly smooth two-dimensional crystals, in which show up only molecular component of the friction force that

In the engineering practice, the auto-compensation systems of wear during friction in the ST regime, usually are formed by selecting (a) the materials of tribocoupling, (b) a composition of lubricants, and (c) a construction of the friction units. As a result of successful material science and engineering solutions, tribosystems are capable of self-organization, in which the process of frictional interaction

friction coefficient and of the size of the rubbing bodies (**Figure 6** [42]).

has "super-hardness" at compression and "super-fluidity" at shear [44].

occurs, such as, during friction of graphene [45].

• Building up the theory and methodology of green tribology.

bution to the existence and development of humanity.

circle of tasks which green tribology is designed to solve.

**4. "Zero-wear" effect: selective transfer**

*Tribology in Materials and Manufacturing - Wear, Friction and Lubrication*

*3D-images of the metal surface before and after treatment with REWITEC 6 months [2].*

direction of rotation independent of the direction of the current flow. Production processes of tidal, water flow and wave energy involve certain specific tribological problems such as lubrication of machine components (by seawater, oils, and greases), their erosion, corrosion, and biofouling, as well as the interaction between these

Geothermal energy plants are widely used now, however, their application is limited to the geographical areas at the edges of tectonic plates. There are several specific tribological issues related to the geothermal energy sources which are

Green tribology as a new area of tribology has a number of challenges. One obvious problem is integration, synergy of its above mentioned focus areas so that they can benefit from each other. Obviously, a lot of researches is needed to integrate the fields of green tribology. Some ideas can be borrowed from the related fields of green chemistry and green engineering, for example, the development of quantitative parameters for assessing the impact of tribological technologies on the environment. It is also important to develop quantitative measures and metrics that would allow us to compare which tribological material, technology, or application is "greener," i.e., produces lower carbon footprint, less waste from worn-out materials,

Green tribology should be integrated into world science and contribute to solving global problems such as resource depletion, environmental pollution and climate change. The application of principles of green tribology by itself, of course, will not solve world problems, and only major scientific achievements can become

scale, green tribology should be extended in the following directions [2].

• Research and development of novel green tribological technologies;

In the face of a large number of tribological problems requiring an early solution, which related to the environmental pollution, crisis of energy and resources on global

• Large-scale deployment of existing knowledge, methods, and technologies of

• Research and development of tribo-techniques to support diversification and

**54**

**Figure 5.**

modes of damage [1, 39].

the key to their solution.

green tribology;

discussed in the literature [1, 5, 15, 39].

and less chemical and heat pollution to the environment.

hybridization of renewable and clean energy;

**3.3 Challenges of green tribology**


Consequently, tribologists should devote all their efforts to the investigation, application and development of green tribology, thereby making a valuable contribution to the existence and development of humanity.
