Wear equation for adhesive wear established through elementary process of wear

doi:10.1016/j.wear.2013.06.016

Wear

Volume 308, Issues 1–2, 30 November 2013, Pages 186-192

https://doi.org/10.1016/j.wear.2013.06.016 Get rights and content

Highlights

•
Wear process was observed from the origin of wear elements for adhesive wear.
•
Generation of wear elements was discussed from slip systems at sliding surface in the elementary wear process.
•
Wear model of adhesive wear from the generation of wear elements to wear particles was presented.
•
Wear equation for adhesive wear was proposed.

Abstract

The research covers the wear processes of adhesive wear from the origin of wear elements (the unitary debris of wear) with a size from a few nanometers to a few tens of nanometers to form transfer particles and lastly wear particles. These particles and wear phenomenon were observed by means of atomic force microscopy (AFM). Furthermore, the formation process of wear particles between the sliding surfaces was optically observed by means of an in situ observation system. From the results of observation of the wear process, we propose a basic wear model of the adhesive wear mechanism and present a wear equation for adhesive wear including physical properties of the sliding surfaces as well as the chemical effect of surrounding gas molecules to the surfaces.

Introduction

Investigation into the mechanism of adhesive wear was undoubtedly triggered by the concept of real contact area (i.e. junction) introduced by Holm [1], [2]. Wear is occurred at the junction fractured by the shear force in frictional motion through the removal of debris of wear. Holm attributed the wear to the removal of atomic level particles or layers at the junction, and afterwards Rabinowicz [3] and Archard [4] proposed that the mechanism for the formation of wear particles stemmed from the removal of the junction itself after fracture of the junction. However, the observation revealed that the size of wear particles was not neither atomic level nor junction itself, but it depended on the mode of adhesive wear after the formation process of transfer and further processes [5], [6]. Of course, severe wear has a particle size from a few tens to a few hundreds μm, while mild wear has a size less than a few μm. Their wear models for adhesive wear and their equations for adhesive wear could not explain the difference in the two modes of adhesive wear. Furthermore, it was most uncertain in their proposed wear equations that both of the wear equations included the factor of probability of removal of wear debris from the junction described as a wear coefficient. However, we suppose the removal of wear debris is not decided by probability but it is absolutely decided by the physical, chemical and mechanical properties of the substances in the tribological processes. The further progressive precise wear equation including the physical and chemical properties of the surfaces for adhesive wear has not proposed after their equations. Therefore, at present we have no wear equations for adhesive wear to explain physical and chemical properties in the wear mechanism.

We recently reported adhesive wear process from the origin of elemental debris of wear particles, which we refer to as “wear elements”; with the size ranges from a few nanometers to a few tens of nanometers observed by means of atomic force microscopy (AFM) to explain elementary process of adhesive wear process [7], [8], [9]. The aim of this investigation is to clarify the progressive process from the origin of wear elements to the formation of wear particles that subsequently disengage from the sliding surfaces as examined by AFM and in situ optical imaging. Furthermore, we propose a basic wear model and present an equation for adhesive wear including the physical and chemical properties in tribological processes according to the characteristics from the origin of elemental debris to the formation process of wear particles on the sliding surfaces.

Section snippets

Experimental

Friction and wear experiments were performed using a pin−on−disk tribotester. The disk specimen (diameter 40 mm) was rotated at a sliding speed of 1.0 mm/s. The pin specimen (diameter 5 mm) was subjected to a normal load of 5.0 N and the sliding surface of the pin was hemispherical in shape. The wear track of the pin specimen on the disk surface was set at 22 mm in diameter. All experiments were performed under dry conditions in air at room temperature and ambient relative humidity (about 40%). At

Observation of pre-sliding surface and the first contact

Fig. 1(a) shows the pre-sliding surface after the steel pin came into contact with the steel disk and tangential force was applied under a load of 5.0 N. At this stage, the pin did not slide on the disk surface in macro scale. Then, the surfaces were separated and the disk surface was observed by AFM. The circle with a diameter of about 30 μm drawn with a broken line on the surface image is the Hertz contact area determined by calculating the ball-flat contact. We can see the real contact area in

Conclusion

In this investigation, we examined the adhesive wear process by means of AFM and in situ optical imaging. The wear process was clarified as originating from wear elements of a few nanometers to a few tens of nanometers in size, which accumulated and formed wear particles. From the observations, we proposed a model for adhesive wear from the origin of wear elements to the formation of wear particles, and we presented an equation for adhesive wear V=(1/3)×(n∕λ)×(b∕a)³×(P×ℓ∕p_m) considering the

Acknowledgements

This research was supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan [Grant-in-Aid for Scientific Research (B), 22360066, 2010].

References (18)

H. Mishina
Surface deformation and formation of original element of wear particles in sliding friction
Wear
(1998)
H. Mishina
Microscopic real time observation of failure, wear and deformation on coating/subsurface
Tribology International
(1999)
A. Hase et al.
Wear elements generated in the elementary process of wear
Tribology International
(2009)
H. Mishina et al.
Generation of wear elements and origin of tribomagnetization phenomenon
Wear
(2010)
H. Mishina
Atmospheric characteristics in friction and wear of metals
Wear
(1992)
H. Mishina
Chemisorption of diatomic gas molecules and atmospheric characteristics in adhesive wear and friction of metals
Wear
(1995)
R. Holm
Über metallische kontaktwiderstände
Wiss Veröff Siemens-Werk
(1929)
R. Holm
Electric contacts: theory and applications
Stockholm
(1946)
E. Rabinowicz
The nature of the static and kinetic coefficient of friction
Journal of Applied Physics
(1951)

There are more references available in the full text version of this article.

Cited by (26)

Effect of fluid pressure on adhesive wear of spherical contact
2023, Tribology International
Lubrication with fluid between two rough surfaces has been extensively studied, while the present work provides an additional principle for its effect on adhesive wear reduction associated with the fluid pressure. In this work, a finite element model for elastoplastic spherical contact with fluid pressure applied on surface is established, considering the realistic ductile failure criteria. It is found that as the fluid pressure increases, the location of fracture nucleation in the front contact region moves towards the contact surface. Two wear modes, namely the detaching and scratching modes, are identified by defining a critical dimensionless fluid pressure. Accordingly, the wear coefficient decreases as the fluid pressure increases, serving as the additional principle for wear reduction in lubrication systems.
Analysis of thin film electrochemical deposition process diffused by carbon tool steels
2023, Results in Chemistry
Chromium (Cr) hard coatings are frequently used for cold shaping and metal cutting in industries. This research work has been performed with the intention of investigating the feasibility of using complex chromium testimony used for phosphating and covering framing apparatus made from a carbon device prepared. Besides, it has been tried to determine the conveying limit of covered phosphate and chromium as well as to evaluate the wear mechanism. This work shows the improvement of wear resistance storing chromium hard covering on materials. Eight apparatus were made, engraved, solidified, tempered, chromed, phosphate, and assembled. The apparatus was installed in machines followed by recording the produced stroke numbers and conducting the tests in grease-free condition. The mechanical characteristics of hardware steel were increased solely by heating it. Instruments made of carbon device steel performed better in terms of erosion, wear, hostile-to-stay parts, and execution when hard chrome plating was used. The strong chromium plating with its excellent antiwear capabilities and high wear obstruction speaks to the optimal arrangement from the standpoint of hardware steel, as well as from the perspective of workpiece surface quality.
Tribological behavior of cold-sprayed titanium/baghdadite composite coatings in dry and simulated body fluid environments
2021, Surface and Coatings Technology
This study reports the tribological behavior of Titanium/Baghdadite cold sprayed composite coatings for artificial human joints in a dry and simulated body fluid environments. Sliding wear tests are performed using a wear test rig to predict the wear resistance of the coatings. An in-depth analysis of the worn-out coatings is also done to establish the wear mechanism for the developed coatings. Scratch adhesion and wettability analyses of the composite coatings have also been reported. The role of microhardness and surface roughness on the performance of the cold sprayed composite coatings is also discussed. It is discovered that cold sprayed composite coatings successfully protect the biomedical grade steel from wear in dry and simulated body fluid environments. Three-body abrasion wear and adhesive wear are the dominant mechanisms observed behind the wear of these coatings. Coatings are found to adhere well with the substrate, and the critical loads for the coatings' delamination are also reported. Furthermore, the coatings are found to be hydrophilic in nature, and the hydrophilicity is observed to be improving with an increase in baghdadite content.
Current failure mechanisms and treatment methods of hot forging tools (dies) - a review
2021, Engineering Failure Analysis
This article presents a critical overview of the current failure mechanisms and treatment methods applied to improve the surface integrity of die tools used in hot forging process. The knowledge from this study enables a longer mean times between failures and cost-effective processes. In literature, several independent review works have been developed to provide a conceptual overview of failures and treatment methods. Despite all these efforts, there is still no comprehensive review of failures and improvement methods in a mutual frame to show the current research status for preventing failures in hot forging tools. In the present study, the current failure mechanisms and treatment methods have been presented based on theoretical knowledge and empirical knowledge obtained from the experience of the authors. This paper aims to provide a conceptual perspective of hot forging tool failures, including wear (abrasive wear, adhesive wear, oxidation, and thermal fatigue cracking), mechanical fatigue cracking, and plastic deformation, and the corresponding treatment methods, including surface treatment (nitriding, hybrid procedure, pad welding, beam technology, and mechanical treatment) and coating techniques (CVD, PVD, duplex coating, PACVD, and TRD) which in turn allows to control and potentially extend the life of die tools used in metal forming process.
Unraveling the significant role of retained austenite on the dry sliding wear behavior of medium manganese steel
2021, Wear
For wear resistant steels, there is generally a linear relationship between the initial hardness and wear resistance, yet a high initial hardness limits the formability of components. The intrinsic ductility of austenite and strain hardening produced from the transformation-induced plasticity (TRIP) effect during service opens a new window for this contradiction. Herein, the wear resistance and the corresponding failure mechanisms of 5Mn steels after different heat treatment processes were evaluated using a ball-on-disk sliding test under dry conditions. The wear behaviors of the counterbodies were also studied to elucidate the wear mechanism of the tribo-system. The results show that the microstructures of the hot-rolled and air-cooled steel were mainly martensite. When the intercritical annealing temperature was relatively low (<695 °C), the microstructure primarily consisted of reversed austenite and ferrite. The samples annealed at 630 °C, 645 °C, 660 °C, and 675 °C had a similar initial hardness, while the sample annealed at 675 °C possessed a wear resistance that was 3.25 times that of the steel annealed at 630 °C. The large difference in the wear resistance was predominately due to the gradient of strain hardening provided by the varied amount and mechanical stability of the retained austenite. The transformation from austenite to martensite, which has an increased hardness, improves the work hardening. A strengthening layer formed with a certain thickness that provided stress support during the wear process and enhanced the wear resistance. When the annealing temperature reached 695 °C, a large amount of secondary martensite was generated from austenite that had a low thermal stability, which improved the initial hardness and wear resistance. The steels with a large amount of martensite had an enhanced wear resistance, but the elongation severely deteriorated, leading to unsatisfactory formability. The present work provides guidance for designing novel steels with an excellent balance of good formability and decent wear resistance by precisely adjusting the characteristics of the retained austenite.
Effect of the adhesion force on the equation of adhesive wear and the generation process of wear elements in adhesive wear of metals
2019, Wear
Citation Excerpt :
Here, assuming that n corresponds to the number of wear elements present in the area of πa2, n is expressed by n ≈ πa2nunit. As previously described, the wear element is the unitary debris of an adhesive wear particle, and the size of wear element was ranging from a few nanometers to a few tens of nanometers by AFM observation [3–6,8]. With respect to the size of the wear elements, it has previously been discussed this is comparable to the size of single-magnetic-domain particles when the metal is a ferromagnetic metal (Ni, Fe, or Co) [5,6].
The effects of the adhesion force on the equation of adhesive wear were investigated by examining the relationship between the adhesion force of actual sliding surfaces and the number of wear elements generated at a junction. The number of wear elements and their generation mechanism in the elementary wear processes were determined by nanoscale observations and by analysis of the sliding surfaces by scanning electron microscopy and atomic-force microscopy. In addition, the adhesion force between actual sliding metal surfaces was measured by a method combining friction-force microscopy and force–distance curve measurement. The adhesion force between metal-probe cantilevers of nine different metals and the surfaces of blocks of the same metal were measured. We propose a modified equation for adhesive wear that takes into account the effect of the adhesion force, and we discuss the precise process for the generation of wear elements.

View all citing articles on Scopus

View full text

Wear equation for adhesive wear established through elementary process of wear

Highlights

Abstract

Introduction

Section snippets

Experimental

Observation of pre-sliding surface and the first contact

Conclusion

Acknowledgements

Wear

Tribology International

Tribology International

Wear

Wear

Wear

Über metallische kontaktwiderstände

Wiss Veröff Siemens-Werk

Electric contacts: theory and applications

Stockholm

The nature of the static and kinetic coefficient of friction

Journal of Applied Physics