Atomic Force Microscopy Study of an Ideally Hard Contact: The Diamond(111)/Tungsten Carbide Interface

Enăchescu, Marius; Oetelaar, R.J.A. van den; Carpick, Robert W.; Ogletree, D. Frank; Flipse, C. F. J.; Salmerón, M.

doi:10.1103/physrevlett.81.1877

Cited by 189 publications

(130 citation statements)

References 28 publications

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“…Instead, the tangential load is shown to be a good indicator of the asperity junction size. This finding is in agreement with observations in recent studies (29,30,35,36,38) that show that, although friction force is always linear with the real contact area at any length scale, the relation between the normal load and the real contact area is largely influenced by the roughness parameters and interfacial adhesion.…”

Section: Discussionsupporting

confidence: 82%

“…3B). We find a linear relation between these two quantities with a proportionality constant of τ , in accordance to previous numerical (29) and experimental (30) studies. This result indicates that the junction is loaded to its elastic shear limit, consistent with the inelasticity (permanent shape change) that is observed at the junction (see also SI Appendix, Fig.…”

Section: Significancesupporting

confidence: 73%

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On the debris-level origins of adhesive wear

Aghababaei

Warner

Molinari

2017

Proc. Natl. Acad. Sci. U.S.A.

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Every contacting surface inevitably experiences wear. Predicting the exact amount of material loss due to wear relies on empirical data and cannot be obtained from any physical model. Here, we analyze and quantify wear at the most fundamental level, i.e., wear debris particles. Our simulations show that the asperity junction size dictates the debris volume, revealing the origins of the long-standing hypothesized correlation between the wear volume and the real contact area. No correlation, however, is found between the debris volume and the normal applied force at the debris level. Alternatively, we show that the junction size controls the tangential force and sliding distance such that their product, i.e., the tangential work, is always proportional to the debris volume, with a proportionality constant of 1 over the junction shear strength. This study provides an estimation of the debris volume without any empirical factor, resulting in a wear coefficient of unity at the debris level. Discrepant microscopic and macroscopic wear observations and models are then contextualized on the basis of this understanding. This finding offers a way to characterize the wear volume in atomistic simulations and atomic force microscope wear experiments. It also provides a fundamental basis for predicting the wear coefficient for sliding rough contacts, given the statistics of junction clusters sizes.Archard's wear law | adhesive wear | friction | wear debris particle | nanotribology T he study of material loss at sliding surfaces, known as "wear," has over two centuries of history (1). Substantial progress occurred in the mid-1900s with a systematic series of wear experiments that showed, within a certain range of applied load, (i) the wear volume (i.e., total volume of wear debris) is independent of apparent area of contact (2, 3), (ii) the wear rate (i.e., wear volume per sliding distance) is linearly proportional to the macroscopic load acting normal to the interface, i.e., Archard's wear law (3, 4), and (iii) the wear volume is proportional to the frictional work (i.e., the product of frictional force and sliding distance), which was first hypothesized by Reye in 1860 (5) and intermittently discussed and observed experimentally (3,(5)(6)(7)(8). The first observation is commonly rationalized by arguing that the wear process is a direct result of contact between elevated surface asperities and is consequently associated with the real area of contact (2, 3). The second observation can then be understood by noting that the real area of contact is observed to be proportional to the macroscopic normal load (2, 9). The third observation follows from the first two if one assumes a wear volume proportional to sliding distance and a tangential force proportional to normal force (i.e., Amontons' first law of friction) (10).Despite the passage of more than 50 years, these wear relations remain fully empirical, and their microscopic origins are still unclear (11). Single-asperity wear simulations (12-14) and atomic force microscope (AFM...

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Section: Discussionsupporting

confidence: 82%

Section: Significancesupporting

confidence: 73%

On the debris-level origins of adhesive wear

Aghababaei

Warner

Molinari

2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Such studies have emphasized the importance of including adhesion between the surfaces in order to better describe the contact properties of elastic systems. Modifications of the AFM that enable the simultaneous measurement of both normal and lateral forces also have allowed the measurement of friction on atomic and molecular scales [23,24]. Friction measurements such as these (figure 4(b)) show that the lateral force is proportional to the contact area.…”

Section: Tribological Investigations Of Single Asperity Contactsmentioning

confidence: 99%

“…Similarly, the friction measured using AFM also varies according to DMT theory illustrating the friction is proportional to the contact area (b) (from Ref. [23], with permission).…”

Section: Environmental Tribologymentioning

confidence: 99%

Frontiers of fundamental tribological research

Perry

Tysoe

2005

Tribol Lett

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This review summarizes recent advances in the area of tribology and the challenges to achieve a molecular level understanding of friction and wear and makes specific recommendations towards attaining such a fundamental understanding. This document represents the results of a two-day workshop, sponsored by the U.S. National Science Foundation, at which participants were charged with defining the outstanding challenges in obtaining a fundamental understanding of friction and wear, thus assisting the National Science Foundation in the effective allocation of resources to address these challenges.

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“…The image has a RMS roughness of 1 -3 nm and consists of 20-50 nm islands of approximately 0.3 nm rms roughness, consistent with previous work. 13,16 The islands are regions of relatively low friction surrounded by stepped features of higher friction ͓Fig. 6͑b͔͒.…”

Section: Compensation For In-plane Tip-sample Displacementmentioning

confidence: 99%

Cantilever tilt compensation for variable-load atomic force microscopy

Cannara

Brukman

Carpick

2005

Review of Scientific Instruments

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In atomic force microscopy ͑AFM͒, typically the cantilever's long axis forms an angle with respect to the plane of the sample's surface. This has consequences for contact mode experiments because the tip end of the cantilever, which is constrained to move along the surface, displaces longitudinally when the applied load varies. As a result, the AFM tip makes contact with a different point on the surface at each load. These different positions lie along the projection of the lever's long axis onto the surface. When not constrained by static friction, the amount of tip-displacement is, to first order, proportional to the load and is shown to be substantial for typical AFM and cantilever geometries. The predictions are confirmed experimentally to within 15% or better. Thus, care should be taken when performing load-dependent contact mode experiments, such as friction versus load, elasticity versus load, or force versus displacement measurements, particularly for heterogeneous or topographically-varying samples. We present a simple method to reliably and precisely compensate for in-plane tip displacement that depends only on the range of vertical motion used to vary the load. This compensation method should be employed in any load-varying AFM experiment that requires the tip to scan the same line or to remain at the same point at each load.

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Atomic Force Microscopy Study of an Ideally Hard Contact: The Diamond(111)/Tungsten Carbide Interface

Cited by 189 publications

References 28 publications

On the debris-level origins of adhesive wear

On the debris-level origins of adhesive wear

Frontiers of fundamental tribological research

Cantilever tilt compensation for variable-load atomic force microscopy

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