Application of the Self-Organization Phenomenon in the Development of Wear Resistant Materials—A Review
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paper_title: Entropy in Tribology: in the Search for Applications

paper_content:

The paper discusses the concept of entropy as applied to friction and wear. Friction and wear are classical examples of irreversible dissipative processes, and it is widely recognized that entropy generation is their important quantitative measure. On the other hand, the use of thermodynamic methods in tribology remains controversial and questions about the practical usefulness of these methods are often asked. A significant part of entropic tribological research was conducted in Russia since the 1970s. Surprisingly, many of these studies are not available in English and still not well known in the West. The paper reviews various views on the role of entropy and self-organization in tribology and it discusses modern approaches to wear and friction, which use the thermodynamic entropic method as well as the application of the mathematical concept of entropy to the dynamic friction effects (e.g., the running-in transient process, stick-slip motion, etc.) and a possible connection between the thermodynamic and information approach. The paper also discusses non-equilibrium thermodynamic approach to friction, wear, and self-healing. In general, the objective of this paper is to answer the frequently asked question “is there any practical application of the thermodynamics in the study of friction and wear?” and to show that the thermodynamic methods have potential for both fundamental study of friction and wear and for the development of new (e.g., self-lubricating) materials.
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paper_title: The Friction Coefficient and Self-Organization Feature on Rake Face when Turning Hardened Steel with Coating Tools

paper_content:

The friction coefficient on rake face was calculated through the cutting forces tested in a series of cutting experiments. These experiments were performed for turning two kinds of hardened steel with four types of coating tool by orthogonal experimental method. The curves of the friction coefficient changing with the cutting process and its dependence on the cutting parameters were analyzed in detail. The results show that the friction coefficient on rake face decreases rapidly during the cutting progress and comes to a steady value, which could be an indication of the self-organization when turning hardened steel with coating tool.
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paper_title: Evidence of self-organized criticality in dry sliding friction

paper_content:

This letter presents experimental results on unlubricated friction, which suggests that stick–slip is described by self-organized criticality (SOC). The data, obtained with a pin-on-disc tribometer examines the variation of the friction force as a function of time—or sliding distance. This is the first time that standard tribological equipment has been used to examine the possibility of SOC. The materials were matching pins and discs of aluminium loaded with 250, 500 and 1000 g masses, and matching M50 steel couples loaded with a 1000 g mass. An analysis of the data shows that the probability distribution of slip sizes follows a power law. In addition, the frequency power spectrum follows a 1/fα pattern with α in the range 1.1–1.3. We perform a careful analysis of all the properties, beyond the two just mentioned, which are required to imply the presence of SOC. Our data strongly support the existence of SOC for stick–slip in dry sliding friction.
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paper_title: Self-organization at the frictional interface for green tribology

paper_content:

Despite the fact that self-organization during friction has received relatively little attention from tribologists so far, it has the potential for the creation of self-healing and self-lubricating materials, which are important for green or environment-friendly tribology. The principles of the thermodynamics of irreversible processes and of the nonlinear theory of dynamical systems are used to investigate the formation of spatial and temporal structures during friction. The transition to the self-organized state with low friction and wear occurs through destabilization of steady-state (stationary) sliding. The criterion for destabilization is formulated and several examples are discussed: the formation of a protective film, microtopography evolution and slip waves. The pattern formation may involve self-organized criticality and reaction-diffusion systems. A special self-healing mechanism may be embedded into the material by coupling the corresponding required forces. The analysis provides the structure-property relationship, which can be applied for the design optimization of composite self-lubricating and self-healing materials for various ecologically friendly applications and green tribology.
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paper_title: Self-Organization and Friction During Sliding

paper_content:

In self-organized sliding processes, the surfaces align to each other during sliding. This alignment leads to a more ordered contact state and significantly influences the frictional behavior. To understand the self-organization sliding processes, experiments were conducted on a pin-on-plate reciprocating sliding tester for various numbers of cycles. In the experiments, soft magnesium pins were slid against hard steel plates of various surface textures (undirectional, 8-ground, and random). Experimental results showed that the transfer layer formation on the steel plates increased with increasing number of cycles for all surfaces textures under both dry and lubricated conditions. The friction also increased with the number of cycles under dry conditions for all of the textures studied. During lubricated conditions, the friction decreased for unidirectional and 8-ground surfaces and increased for random surfaces with the number of cycles. Furthermore, the friction and transfer layer formation depend on the surface textures under both dry and lubricated conditions during the first few sliding cycles. Later on, it is less dependent of surface textures. The variation in the coefficient of friction under both dry and lubrication conditions were attributed to the self-organization process that occurred during repeated sliding.
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paper_title: Non-equilibrium work distribution for interacting colloidal particles under friction

paper_content:

We experimentally investigate the non-equilibrium steady-state distribution of the work done by an external force on a mesoscopic system with many coupled degrees of freedom: a colloidal crystal mechanically driven across a commensurate periodic light field. Since this system mimics the spatiotemporal dynamics of a crystalline surface moving on a corrugated substrate, our results show general properties of the work distribution for atomically flat surfaces undergoing friction. We address the role of several parameters which can influence the shape of the work distribution, e.g. the number of particles used to locally probe the properties of the system and the time interval to measure the work. We find that, when tuning the control parameters to induce particle depinning from the substrate, there is an abrupt change of the shape of the work distribution. While in the completely static and sliding friction regimes the work distribution is Gaussian, non-Gaussian tails show up due to the spatiotemporal heterogeneity of the particle dynamics during the transition between these two regimes.
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paper_title: On the thermodynamics of degradation

paper_content:

The science base that underlies modelling and analysis of machine reliability has remained substantially unchanged for decades. Therefore, it is not surprising that a significant gap exists between available machinery technology and science to capture degradation dynamics for prediction of failure. Further, there is a lack of a systematic technique for the development of accelerated failure testing of machinery components. This article develops a thermodynamic characterization of degradation dynamics, which employs entropy, a measure of thermodynamic disorder, as the fundamental measure of degradation; this relates entropy generation to irreversible degradation and shows that components of material degradation can be related to the production of corresponding thermodynamic entropy by the irreversible dissipative processes that characterize the degradation. A theorem that relates entropy generation to irreversible degradation, via generalized thermodynamic forces and degradation forces, is constructed. This theorem provides the basis of a structured method for formulating degradation models consistent with the laws of thermodynamics. Applications of the theorem to problems involving sliding wear and fretting wear, caused by effects of friction and associated with tribological components, are presented.
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paper_title: Self-Organization during Friction of Slide Bearing Antifriction Materials

paper_content:

This article discusses the peculiarities of self-organization behavior and formation of dissipative structures during friction of antifriction alloys for slide bearings against a steel counterbody. It shows that during self-organization, the moment of friction in a tribosystem may be decreasing with the load growth and in the bifurcations of the coefficient of friction with respect to load. Self-organization and the formation of dissipative structures lead to an increase in the seizure load.
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paper_title: Modern Thermodynamics: From Heat Engines to Dissipative Structures

paper_content:

I Historical Roots: From Heat Engines to Cosmology ::: 1 Basic Concepts and the Law of Gases ::: 2 The First Law of Thermodynamics ::: 3 The Second Law of Thermodynamics and the Arrow of Time ::: 4 Entropy in the Realm of Chemical Reactions ::: ::: II Equilibrium Thermodynamics ::: 5 Extremum Principles and General Thermodynamics Relations ::: 6 Basic Thermodynamics of Gases, Liquids and Solids ::: 7 Thermodynamics of Phase Change ::: 8 Thermodynamics of Solutions ::: 9 Thermodynamics of Chemical Transformations ::: 10 Fields and Internal Degrees of Freedom ::: 11 Thermodynamics of Radiation ::: ::: III Fluctuations and Stability ::: 12 The Gibbs Stability Theory ::: 13 Critical Phenomena and Configurational Heat Capacity ::: 14 Entropy Productions, Fluctuations and Small Systems ::: ::: IV Linear Nonequilibrium Thermodynamics ::: 15 Nonequilibrium Thermodynamics: The Foundations ::: 16 Nonequilibrium Thermodynamics: The Linear Regime ::: 17 Nonequilibrium Stationary State and Their Stability: Linear Regime ::: ::: V Order Through Fluctuations ::: 18 Nonlinear Thermodynamics ::: 19 Dissipative Structures ::: 20 Elements of Statistical Thermodynamics ::: 21 Self-Organization and Dissipative Structures in Nature
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paper_title: Nano-crystalline filtered arc deposited (FAD) TiAlN PVD coatings for high-speed machining applications

paper_content:

Abstract The main advantage of the filtered arc deposition (FAD) technique is a significant grain refinement that leads to the formation of nano-crystalline (grain size approx. 60–80 nm) PVD coatings. This technique improves the wear resistance of FAD TiAlN coatings under high-speed machining conditions when cutting tool oxidation wear is dominant. A study of the surface structure characteristics of the FAD TiAlN coatings using SEM, EDS, TEM, AES, SIMS and EELFS was performed. The microhardness of the coatings were measured. The microstructure of the chips was analyzed. The compression of the chips as well as shear angle was measured. The friction parameter on the rake surface of the tools was determined in-situ. It was shown that the major cause of the high wear resistance of the FAD coatings during high-speed machining was the formation of the thin protective oxide films on the cutting tool surface. The grain size refinement of the coating promotes the formation of protective alumina films. These films are formed at the surface of nano-crystalline FAD TiAlN coating during high-speed machining. They mainly consist of protective alumina, whereas the films that are forming on the surface of TiAlN commercial coatings with coarser grains consist only of non-protective titania. The formation of the protective alumina films, composed of complicated amorphous–crystalline structures, significantly improves the friction and wear performance of coated tools. The tendency of the work piece material to adhere is reduced and considerably more heat is dissipated via chip removal. This is a major cause of the enhanced wear resistance of the FAD coating technique. Tribo-oxidation during cutting is a typical process of the self-organization of TiAlN coatings that results in a quasi-stabilization of cutting tool wear. The self-organization and friction control for coated cutting tools is considered based on a non-equilibrium thermodynamic approach.
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paper_title: Self-Organization during Friction in Complex Surface Engineered Tribosystems

paper_content:

Self-organization during friction in complex surface engineered tribosystems is investigated. The probability of self-organization in these complex tribosystems is studied on the basis of the theoretical concepts of irreversible thermodynamics. It is shown that a higher number of interrelated processes within the system result in an increased probability of self-organization. The results of this thermodynamic model are confirmed by the investigation of the wear performance of a novel Ti0.2Al0.55Cr0.2Si0.03Y0.02N/Ti0.25Al0.65Cr0.1N (PVD) coating with complex nano-multilayered structure under extreme tribological conditions of dry high-speed end milling of hardened H13 tool steel.
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paper_title: The chemical basis of morphogenesis

paper_content:

It is suggested that a system of chemical substances, called morphogens, reacting together and diffusing through a tissue, is adequate to account for the main phenomena of morphogenesis. Such a system, although it may originally be quite homogeneous, may later develop a pattern or structure due to an instability of the homogeneous equilibrium, which is triggered off by random disturbances. Such reaction-diffusion systems are considered in some detail in the case of an isolated ring of cells, a mathematically convenient, though biologically unusual system. The investigation is chiefly concerned with the onset of instability. It is found that there are six essentially different forms which this may take. In the most interesting form stationary waves appear on the ring. It is suggested that this might account, for instance, for the tentacle patterns onHydra and for whorled leaves. A system of reactions and diffusion on a sphere is also considered. Such a system appears to account for gastrulation. Another reaction system in two dimensions gives rise to patterns reminiscent of dappling. It is also suggested that stationary waves in two dimensions could account for the phenomena of phyllotaxis.The purpose of this paper is to discuss a possible mechanism by which the genes of a zygote may determine the anatomical structure of the resulting organism. The theory does not make any new hypotheses; it merely suggests that certain well-known physical laws are sufficient to account for many of the facts. The full understanding of the paper requires a good knowledge of mathematics, some biology, and some elementary chemistry. Since readers cannot be expected to be experts in all of these subjects, a number of elementary facts are explained, which can be found in text-books, but whose omission would make the paper difficult reading.
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paper_title: On the thermodynamics of degradation

paper_content:

The science base that underlies modelling and analysis of machine reliability has remained substantially unchanged for decades. Therefore, it is not surprising that a significant gap exists between available machinery technology and science to capture degradation dynamics for prediction of failure. Further, there is a lack of a systematic technique for the development of accelerated failure testing of machinery components. This article develops a thermodynamic characterization of degradation dynamics, which employs entropy, a measure of thermodynamic disorder, as the fundamental measure of degradation; this relates entropy generation to irreversible degradation and shows that components of material degradation can be related to the production of corresponding thermodynamic entropy by the irreversible dissipative processes that characterize the degradation. A theorem that relates entropy generation to irreversible degradation, via generalized thermodynamic forces and degradation forces, is constructed. This theorem provides the basis of a structured method for formulating degradation models consistent with the laws of thermodynamics. Applications of the theorem to problems involving sliding wear and fretting wear, caused by effects of friction and associated with tribological components, are presented.
---
paper_title: Self-Organization during Friction of Slide Bearing Antifriction Materials

paper_content:

This article discusses the peculiarities of self-organization behavior and formation of dissipative structures during friction of antifriction alloys for slide bearings against a steel counterbody. It shows that during self-organization, the moment of friction in a tribosystem may be decreasing with the load growth and in the bifurcations of the coefficient of friction with respect to load. Self-organization and the formation of dissipative structures lead to an increase in the seizure load.
---
paper_title: The Friction Coefficient and Self-Organization Feature on Rake Face when Turning Hardened Steel with Coating Tools

paper_content:

The friction coefficient on rake face was calculated through the cutting forces tested in a series of cutting experiments. These experiments were performed for turning two kinds of hardened steel with four types of coating tool by orthogonal experimental method. The curves of the friction coefficient changing with the cutting process and its dependence on the cutting parameters were analyzed in detail. The results show that the friction coefficient on rake face decreases rapidly during the cutting progress and comes to a steady value, which could be an indication of the self-organization when turning hardened steel with coating tool.
---
paper_title: Evidence of self-organized criticality in dry sliding friction

paper_content:

This letter presents experimental results on unlubricated friction, which suggests that stick–slip is described by self-organized criticality (SOC). The data, obtained with a pin-on-disc tribometer examines the variation of the friction force as a function of time—or sliding distance. This is the first time that standard tribological equipment has been used to examine the possibility of SOC. The materials were matching pins and discs of aluminium loaded with 250, 500 and 1000 g masses, and matching M50 steel couples loaded with a 1000 g mass. An analysis of the data shows that the probability distribution of slip sizes follows a power law. In addition, the frequency power spectrum follows a 1/fα pattern with α in the range 1.1–1.3. We perform a careful analysis of all the properties, beyond the two just mentioned, which are required to imply the presence of SOC. Our data strongly support the existence of SOC for stick–slip in dry sliding friction.
---
paper_title: Self-organization at the frictional interface for green tribology

paper_content:

Despite the fact that self-organization during friction has received relatively little attention from tribologists so far, it has the potential for the creation of self-healing and self-lubricating materials, which are important for green or environment-friendly tribology. The principles of the thermodynamics of irreversible processes and of the nonlinear theory of dynamical systems are used to investigate the formation of spatial and temporal structures during friction. The transition to the self-organized state with low friction and wear occurs through destabilization of steady-state (stationary) sliding. The criterion for destabilization is formulated and several examples are discussed: the formation of a protective film, microtopography evolution and slip waves. The pattern formation may involve self-organized criticality and reaction-diffusion systems. A special self-healing mechanism may be embedded into the material by coupling the corresponding required forces. The analysis provides the structure-property relationship, which can be applied for the design optimization of composite self-lubricating and self-healing materials for various ecologically friendly applications and green tribology.
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paper_title: The interrelation of the run-in ability of bronzes and aluminum-based antifriction alloys with their mechanical properties and degree of alloying

paper_content:

Combined tests are carried out to determine the mechanical characteristics of pilot antifriction alloys based on aluminum and BrO4Ts4S17 commercial bronze; they are also tested in the laboratory tests for run-in ability. The interrelation of the mechanical characteristics of these pilot alloys with their run-in ability is determined. The interrelation of the mechanical characteristics of aluminum-based alloys with their run-in ability is considered for various degrees of alloying with hardening elements and elements that provide the presence of the soft structural constituent.
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paper_title: Structural changes of the Cu surface of a Cu/ZnO/Al2O3 catalyst, resulting from oxidation and reduction, probed by CO infrared spectroscopy

paper_content:

Abstract The morphology of the Cu surface of a Cu/ZnO/Al 2 O 3 (60:30:10) catalyst, produced by reduction of the copper oxide component of the catalyst either with H 2 or CO, has been probed by measuring the IR spectra of CO adsorbed on these surfaces. Pre-reduction in H 2 produces a Cu surface, which contains the (110) and (211) faces and which is active in CO 2 decomposition. Re-reduction of the CO 2 -oxidised Cu surface in CO results in a twofold increase in the Cu(211) surface. Re-reduction of the CO 2 -oxidised Cu surface in H 2 results in the restoration of the original Cu morphology, i.e. in a decrease in the Cu(211) surface population. Initial reduction of the copper oxide component of the Cu/ZnO/Al 2 O 3 catalyst by CO produces a surface, which is inactive in the decomposition of CO 2 .
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paper_title: Friction of CVD Diamond on Intermetallide

paper_content:

The present article presents the results of triboengineering tests of polycrystalline diamonds deposited chemically from the gaseous phase together with intermetallides of the Al-Ti system. The conditions are determined when the diamond wears intensively; these conditions appear due to the use of a metallic catalysis precursor as a counterbody. The study results are expected to contributed to the development of techniques for machining of diamonds of industrial dimensions.
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paper_title: Catalytic effect during friction

paper_content:

The possibility of influencing friction-induced processes and friction parameters through catalytic phenomena is discussed. A catalytic effect is shown using examples of material treatment and friction with the collection of electric current. The friction-induced catalytic effect is described based on nonequilibrium thermodynamics and the theory of self-organization. Addition of a catalyst into rubbing materials can help increase the wear rate of the materials under mechanical treatment or decrease the wear rate of wear-resistant materials by accelerating spontaneous or nonspontaneous physicochemical processes, respectively.
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paper_title: Comparison of scoring resistance of new antifriction aluminum alloys and tradition al antifriction bronze

paper_content:

The results of tests on the scoring resistance of newly developed aluminum antifriction alloys and antifriction bronze have been presented. It has been shown that the load of scoring for aluminum alloys is significantly higher than for bronze with a maximum content of the soft structural component, i.e., the best antifriction bronze.
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paper_title: Non-equilibrium work distribution for interacting colloidal particles under friction

paper_content:

We experimentally investigate the non-equilibrium steady-state distribution of the work done by an external force on a mesoscopic system with many coupled degrees of freedom: a colloidal crystal mechanically driven across a commensurate periodic light field. Since this system mimics the spatiotemporal dynamics of a crystalline surface moving on a corrugated substrate, our results show general properties of the work distribution for atomically flat surfaces undergoing friction. We address the role of several parameters which can influence the shape of the work distribution, e.g. the number of particles used to locally probe the properties of the system and the time interval to measure the work. We find that, when tuning the control parameters to induce particle depinning from the substrate, there is an abrupt change of the shape of the work distribution. While in the completely static and sliding friction regimes the work distribution is Gaussian, non-Gaussian tails show up due to the spatiotemporal heterogeneity of the particle dynamics during the transition between these two regimes.
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Title: Application of the Self-Organization Phenomenon in the Development of Wear Resistant Materials—A Review

Section 1: Introduction
Description 1: Briefly introduce the topic of nonequilibrium thermodynamics and self-organization in tribology, highlighting the gap in practical applications for developing wear-resistant materials.

Section 2: The Physical Meaning of the Self-Organization Phenomenon as Applied to Friction
Description 2: Discuss the concept of dissipative structures as defined by Prigogine, detailing the relationship between self-organization, entropy production, and friction.

Section 3: Examples of Practical Application of the Phenomena of Self-Organization in Friction
Description 3: Provide illustrative examples of how self-organization can be applied to reduce wear in various tribosystems, such as sliding electrical contacts and newly developed antifriction aluminum alloys.

Section 4: Conclusions
Description 4: Summarize the key properties, attributes, and definitions of self-organization in friction. Highlight the practical benefits and applications of self-organization in developing wear-resistant materials.