The contribution of micro/nano-tribology to the interpretation of dry friction

2000 ◽  
Vol 214 (1) ◽  
pp. 11-22 ◽  
Author(s):  
K. L. Johnson
Keyword(s):  
Dry Friction ◽  
Sliding Friction ◽  
Surface Force ◽  
The Real ◽  
Real Area Of Contact ◽  
Atomic Force ◽  
Dislocation Mechanics ◽  
Asperity Contacts ◽  
Friction Measurements

Fundamental studies of the mechanics and physics of dry sliding friction between solid surfaces have been impeded in the past by surface roughness and the difficulty of determining the real area of contact. The last decade has seen an explosive development of techniques to study friction at single-asperity contacts in which the real and apparent contact areas coincide. The contribution of these developments to interpreting dry friction is discussed in this paper. Experiments with smooth compliant rubber led to an appreciation of the role of adhesive forces and to including its effects in contact mechanics. Atomically smooth surfaces are obtained in the surface force apparatus (SFA) through the property of mica to cleave on atomic planes, and in the atomic force/friction microscope (AFM) by the use of nanometre size contacts on single crystals. Based on friction measurements in the SFA and AFM, a hypothesis is advanced that sliding of atomically smooth contacts takes place by the nucleation and propagation of dislocation-like defects through the interface. An analysis by Hurtado and Kim [29] using dislocation mechanics suggests a ‘scale effect’ in which friction is governed by resistance to nucleation in very small contacts and by resistance to propagation in larger contacts.

Atomic force microscopy and direct surface force measurements (IUPAC Technical Report)

2005 ◽  
Vol 77 (12) ◽  
pp. 2149-2170 ◽  
Author(s):  
John Ralston ◽  
Ian Larson ◽  
Mark W. Rutland ◽  
Adam A. Feiler ◽  
Mieke Kleijn
Keyword(s):  
Surface Force ◽  
Distinct Advantage ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Technical Report ◽  
Relative Separation ◽  
Frictional Forces ◽  
Probe Microscope ◽  
Friction Measurements

The atomic force microscope (AFM) is designed to provide high-resolution (in the ideal case, atomic) topographical analysis, applicable to both conducting and nonconducting surfaces. The basic imaging principle is very simple: a sample attached to a piezoelectric positioner is rastered beneath a sharp tip attached to a sensitive cantilever spring. Undulations in the surface lead to deflection of the spring, which is monitored optically. Usually, a feedback loop is employed, which holds the spring deflection constant, and the corresponding movement of the piezoelectric positioner thus generates the image. From this it can be seen that the scanning AFM has all the attributes necessary for the determination of surface and adhesion forces; a sensitive spring to determine the force, a piezoelectric crystal to alter the separation of the tip and surface, which if sufficiently well-calibrated also allows the relative separation of the tip and surface to be calculated. One can routinely quantify both the net surface force (and its separation dependence) as the probe approaches the sample, and any adhesion (pull-off) force on retraction. Interactions in relevant or practical systems may be studied, and, in such cases, a distinct advantage of the AFM technique is that a particle of interest can be attached to the end of the cantilever and the interaction with a sample of choice can be studied, a method often referred to as colloid probe microscopy. The AFM, or, more correctly, the scanning probe microscope, can thus be used to measure surface and frictional forces, the two foci of this article. There have been a wealth of force and friction measurements performed between an AFM tip and a surface, and many of the calibration and analysis issues are identical to those necessary for colloid probe work. We emphasize that this article confines itself primarily to elements of colloid probe measurement using the AFM.

Self-Organized Criticality in Nanotribology

2003 ◽  
Vol 782 ◽  
Author(s):  
Micha Adler ◽  
John Ferrante ◽  
Alan Schilowitz ◽  
Dalia Yablon ◽  
Fredy Zypman
Keyword(s):  
Dry Friction ◽  
Sliding Friction ◽  
Stick Slip ◽  
Slip Mechanism ◽  
Flat Surfaces ◽  
Self Organized ◽  
Atomic Force ◽  
Lateral Forces ◽  
Self Organized Criticality ◽  
Sliding Distance

ABSTRACTWe present experimental results on dry friction, which are consistent with the hypothesis that the stick-slip mechanism for energy release is described by self-organized criticality. The data, obtained with an Atomic Force Microscope set to measure lateral forces– examines the variation of the friction force as a function of time – or sliding distance. The materials studied were nominally flat surfaces of mica, quartz, silica and steel. An analysis of the data shows that the probability distribution of slip sizes follows a power law. Our data strongly supports the existence of self-organized criticality for nano-stick-slip in dry sliding friction.

Sliding Friction by Atomic Force Microscopy

1998 ◽  
Vol 543 ◽  
Author(s):  
V. Pasquier ◽  
J. M. Drake
Keyword(s):  
Atomic Force Microscopy ◽  
Sliding Friction ◽  
Lateral Force ◽  
Lateral Force Microscopy ◽  
Force Microscopy ◽  
Load Dependence ◽  
Silica Surfaces ◽  
Atomic Force ◽  
Friction Measurements ◽  
Force Calibration

AbstractLateral Force Microscopy offers the possibility of exploring tribological properties of interfaces atthe nanoscale. Our research focused on some crucial conditions that must be fuffilled to obtainquantitative and reliable LFM friction measurements. We have characterized the mechanical andvibrational properties of the cantilever. Precise force calibration were made based on ourknowledge of the intrinsic coupling modes of the cantilever. We report measurements of the slidingfriction between two silica surfaces. The load dependence of the friction force was analyzedassuming different models for the contact, from Hertzian to Amontons law.

TRIBOLOGICAL PROPERTIES OF DIAMON D-LIKE CARBON COATINGS AT FRICTION JOINTS LUBRICATED WITH IONIC LIQUID

Tribologia ◽  
2019 ◽  
Vol 287 (5) ◽  
pp. 59-69
Author(s):  
Krystian MILEWSKI ◽  
Monika MADEJ ◽  
Dariusz OZIMINA
Keyword(s):  
Ionic Liquid ◽  
Tribological Properties ◽  
Dry Friction ◽  
Sliding Friction ◽  
Chemical Vapour ◽  
Carbon Coatings ◽  
Atomic Force ◽  
Coefficient Of Sliding Friction ◽  
Before And After ◽  
Deposition Processes

The paper reports the study of a-C: H and a-C:H:Si diamond-like carbon coatings obtained in plasma-assisted chemical vapour deposition processes PACVD. The influence of the coatings on tribological properties of tribopairs under dry friction and in lubrication with synthetic oil PAO-8 and selected ionic liquid was evaluated. To perform the analysis, 100Cr6 steel samples uncoated and coated with a-C:H and a-C:H:Si were compared. Surface topography studies were performed using an atomic force microscope. Using SEM with an EDS analyser, the surface morphology of the coatings was observed, and the elements contained in the coatings were identified. Tribotests were carried out in a ball-on-disc tribotester under dry friction and with lubricants. The characteristics of the texture of the samples before and after the tribotests were determined using a confocal microscope in an interferometric mode. The test results showed that the tribo-pairs with a-C:H in lubrication with ionic liquid had the best tribological characteristics, i.e., the lowest coefficient of sliding friction.

An Study of Influence of Imperfections on the Delamination of Diamond-Like Carbon Films

2002 ◽  
Vol 719 ◽  
Author(s):  
Myoung-Woon Moon ◽  
Kyang-Ryel Lee ◽  
Jin-Won Chung ◽  
Kyu Hwan Oh
Keyword(s):  
Cross Sections ◽  
Focused Ion Beam ◽  
Imaging System ◽  
Ion Beam ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Glass Substrates ◽  
Atomic Force ◽  
Initiation And Propagation

AbstractThe role of imperfections on the initiation and propagation of interface delaminations in compressed thin films has been analyzed using experiments with diamond-like carbon (DLC) films deposited onto glass substrates. The surface topologies and interface separations have been characterized by using the Atomic Force Microscope (AFM) and the Focused Ion Beam (FIB) imaging system. The lengths and amplitudes of numerous imperfections have been measured by AFM and the interface separations characterized on cross sections made with the FIB. Chemical analysis of several sites, performed using Auger Electron Spectroscopy (AES), has revealed the origin of the imperfections. The incidence of buckles has been correlated with the imperfection length.

EVERYDAY PRACTICE OF MOTHERS IN A PROVINCIAL SOVIET CITY IN THE 1950–60S

2020 ◽  
pp. 42-51
Author(s):  
Irina V. Bogdashina
Keyword(s):  
Well Being ◽  
Reproductive Behaviour ◽  
Working Mother ◽  
Material Wealth ◽  
The Real ◽  
Raising Children ◽  
Diffi Cult ◽  
The Family ◽  
The Right

The article reveals the measures undertaken by the Soviet state during the “thaw” in the fi eld of reproductive behaviour, the protection of motherhood and childhood. Compilations, manuals and magazines intended for women were the most important regulators of behaviour, determining acceptable norms and rules. Materials from sources of personal origin and oral history make it possible to clearly demonstrate the real feelings of women. The study of women’s everyday and daily life in the aspect related to pregnancy planning, bearing and raising children will allow us to compare the real situation and the course of implementation of tasks in the fi eld of maternal and child health. The demographic surge in the conditions of the economy reviving after the war, the lack of preschool institutions, as well as the low material wealth of most families, forced women to adapt to the situation. In the conditions of combining the roles of mother, wife and female worker, women entrusted themselves with almost overwork, which affected the health and well-being of the family. The procedure for legalising abortion gave women not only the right to decide the issue of motherhood themselves, but also made open the already necessary, but harmful to health, habitual way of birth control. Maternal care in diffi cult material and housing conditions became the concern of women and the older generation, who helped young women to combine the role of a working mother, which the country’s leadership confi dently assigned to women.

The role of buy-side anchoring bias: Evidence from the real estate market

2016 ◽  
Vol 38 ◽  
pp. 34-58 ◽  
Author(s):  
Chuang-Chang Chang ◽  
Ching-Hsiang Chao ◽  
Jin-Huei Yeh
Keyword(s):  
Real Estate ◽  
Real Estate Market ◽  
The Real ◽  
The Real Estate ◽  
The Real Estate Market ◽  
Anchoring Bias
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