scholarly journals Friction of a Steel Ball on a Single Crystal of Ice

1977 ◽  
Vol 19 (81) ◽  
pp. 225-235 ◽  
Author(s):  
Katutosi Tusima
Keyword(s):  
Single Crystal ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Steel Ball ◽  
Low Friction ◽  
Prismatic Plane ◽  
Ice Friction ◽  
The Coefficient Of Friction ◽  
Pressure Melting ◽  
Definite Temperature

AbstractThis paper presents the results of a study carried out to explain the low friction on ice. Friction of a steel ball on a single crystal of ice was measured as a function of load, velocity, temperature, and diameter of slider. It was found that even when the velocity was very small (1.5 - 10-7 to 1.8-10–3 m/s) the coefficient of friction was very small ranging from 0.005 to 0.2, although friction on the prismatic plane was twice as large as that on the basal plane. The coefficient of friction increased with load, which means that Amonton’s classical law of friction is not applicable to ice. The coefficient of friction increased with decreasing velocity, which may result from the creep of ice in the contact area. The friction strongly increased as the temperature became close to °C. A minimum friction was observed for a definite temperature. It was found that the explanation of the results obtained is given satisfactorily neither by the classic pressure-melting theory nor by the friction-melting theory, but only by adhesion theory.

Friction of a Steel Ball on a Single Crystal of Ice

1977 ◽  
Vol 19 (81) ◽  
pp. 225-235 ◽  
Author(s):  
Katutosi Tusima
Keyword(s):  
Single Crystal ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Steel Ball ◽  
Low Friction ◽  
Prismatic Plane ◽  
Ice Friction ◽  
The Coefficient Of Friction ◽  
Pressure Melting ◽  
Definite Temperature

Abstract This paper presents the results of a study carried out to explain the low friction on ice. Friction of a steel ball on a single crystal of ice was measured as a function of load, velocity, temperature, and diameter of slider. It was found that even when the velocity was very small (1.5 - 10-7 to 1.8-10–3 m/s) the coefficient of friction was very small ranging from 0.005 to 0.2, although friction on the prismatic plane was twice as large as that on the basal plane. The coefficient of friction increased with load, which means that Amonton’s classical law of friction is not applicable to ice. The coefficient of friction increased with decreasing velocity, which may result from the creep of ice in the contact area. The friction strongly increased as the temperature became close to °C. A minimum friction was observed for a definite temperature. It was found that the explanation of the results obtained is given satisfactorily neither by the classic pressure-melting theory nor by the friction-melting theory, but only by adhesion theory.

Study of the micro/nano-texture design to improve the friction properties of DLC thin films

2021 ◽  
pp. 2140027
Author(s):  
Young Woo Kwon ◽  
Mun Ki Bae ◽  
Ri-Ichi Murakami ◽  
Tae Hwan Jang ◽  
Tae Gyu Kim
Keyword(s):  
Thin Film ◽  
Coefficient Of Friction ◽  
Surface Friction ◽  
Low Friction ◽  
Frictional Wear ◽  
The Coefficient Of Friction ◽  
Surface Contact Area ◽  
Photolithography Process ◽  
Texture Design ◽  
Pattern Width

In this study, a DLC pattern was fabricated through a photolithography process that constitutes a part of the semiconductor process, to investigate the frictional wear characteristics. The photolithography was used to produce negative patterns with a pattern width of 10 [Formula: see text]m or 20 [Formula: see text]m and a pattern depth of 500 nm on the DLC surface. The change in the coefficient of friction of the surface was investigated through a ball-on-disk tribology test on the fabricated micro/nano-sized DLC pattern. The DLC pattern fabricated by the photolithography process showed a superior coefficient of friction to that of the general DLC sample. These results show that the decrease in the surface friction coefficient of the patterned DLC thin film is due to the reduction in the surface contact area owing to the modification of the micro/nano-texture of the surface as well as the low friction characteristics of the DLC.

Stresses Due to Tangential and Normal Loads on an Elastic Solid With Application to Some Contact Stress Problems

1953 ◽  
Vol 20 (2) ◽  
pp. 157-166
Author(s):  
J. O. Smith ◽  
Chang Keng Liu
Keyword(s):  
Plane Strain ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Normal Load ◽  
Elastic Solid ◽  
Real Variable ◽  
The Body ◽  
Shearing Stress ◽  
Tangential Load ◽  
The Coefficient Of Friction

Abstract The results of two-dimensional approach using real variable method to Hertz’s problem of contact of elastic bodies are presented. Both normal and tangential loads are assumed to be distributed in Hertzian fashion over the area of contact. The magnitude of the intensity of the tangential load is assumed to be linearly proportional to that of the normal load when sliding motion of the body is impending. The stresses in the elastic body due to the application of these loads on its boundary are presented in closed form for both plane-stress and plane-strain cases. A numerical value of f = 1/3 is assumed for the linear proportionality (coefficient of friction) between the tangential and normal loads in order that the distribution of stresses may be illustrated. The significance of the stress distribution, across the contact area and in the body, is also discussed. It is shown that when the combination of loads considered in the paper are applied at the contact area of bodies in contact the maximum shearing stress may be at the surface instead of beneath the surface. For example, for plane strain, if the coefficient of friction is f = 1/3, the maximum shearing stress is at the surface and is 43 per cent larger than the maximum shearing stress, which would be below the surface, that occurs when the normal force acts alone. The effect of range of normal stress and of shearing stress on the plane of maximum shear and on the plane of maximum octahedral shear on failure by progressive fracture (fatigue) is discussed.

Friction and wear studies of silicon in sliding contact with thin-film magnetic rigid disks

1993 ◽  
Vol 8 (7) ◽  
pp. 1611-1628 ◽  
Author(s):  
Bharat Bhushan ◽  
Sreekanth Venkatesan
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Coefficient Of Friction ◽  
Amorphous Carbon ◽  
Friction And Wear ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Carbon Transfer ◽  
Zn Ferrite ◽  
The Coefficient Of Friction

Silicon is an attractive material for the construction of read/write head sliders in magnetic recording applications from the viewpoints of ease of miniaturization and low fabrication cost. In the present investigation we have studied the friction and wear behavior of single-crystal, polycrystalline, ion-implanted, thermally oxidized (wet and dry), and plasma-enhanced chemical vapor deposition (PECVD) oxide-coated silicon pins while sliding against lubricated and unlubricated thin-film disks. For comparison, tests have also been conducted with Al2O3–TiC and Mn–Zn ferrite pins which are currently used as slider materials. With single-crystal silicon the rise in the coefficient of friction with sliding cycles is faster compared to Al2O3–TiC and Mn–Zn ferrite pins. In each case, the rise in friction is associated with the burnishing of the disk surface and transfer of amorphous carbon and lubricant (in the case of lubricated disks) from the disk to the pin. Thermally oxidized (under dry oxygen conditions) single-crystal silicon and PECVD oxide-coated single-crystal silicon exhibit excellent tribological characteristics while sliding against lubricated disks, and we believe this is attributable to the chemical passivity of the oxide coating. In dry nitrogen, the coefficient of friction for single-crystal silicon sliding against lubricated disks behaves differently than in air, decreasing from an initial value of 0.2 to less than 0.05 within 5000 cycles of sliding. We believe that silicon/thin-film disk interface friction and wear is governed by the uniformity and tenacity of the amorphous carbon transfer film and oxygen-enhanced fracture of silicon.

scholarly journals The Adhesion, Friction, and Wear of Binary Alloys in Contact With Single-Crystal Silicon Carbide

1981 ◽  
Vol 103 (2) ◽  
pp. 180-187 ◽  
Author(s):  
Kazuhisa Miyoshi ◽  
D. H. Buckley
Keyword(s):  
Silicon Carbide ◽  
Single Crystal ◽  
Coefficient Of Friction ◽  
Friction And Wear ◽  
Single Crystal Silicon ◽  
Solute Concentration ◽  
Crystal Silicon ◽  
Iron Base ◽  
The Coefficient Of Friction ◽  
Adhesion Friction

Sliding friction experiments were conducted with various iron-base alloys (alloying elements were Ti, Cr, Mn, Ni, Rh, and W) in contact with a single-crystal silicon carbide (0001) surface in vacuum. Results indicate atomic size misfit and concentration of alloying elements play a dominant role in controlling adhesion, friction, and wear properties of iron-base binary alloys. The controlling mechanism of the alloy properties is as an intrinsic effect involving the resistance to shear fracture of cohesive bonding in the alloy. The coefficient of friction generally increases with an increase in solute concentration. The coefficient of friction increases as the solute-to-iron atomic radius ratio increases or decreases from unity. Alloys having higher solute concentration produce more transfer to silicon carbide than do alloys having low solute concentrations. The chemical activity of the alloying element is also an important parameter in controlling adhesion and friction of alloys.

Multiscale Modeling of Frictional Behavior of Highly-Ordered Carbon Nanotube/Ceramic Nanocomposites

2006 ◽  
Vol 978 ◽  
Author(s):  
Zhenhai Xia ◽  
William A Curtin ◽  
Pradeep Guduru
Keyword(s):  
Carbon Nanotube ◽  
Coefficient Of Friction ◽  
Md Simulation ◽  
Interaction Force ◽  
Thick Wall ◽  
Low Friction ◽  
Frictional Behavior ◽  
The Coefficient Of Friction ◽  
Cnt Arrays ◽  
Ceramic Nanocomposites

AbstractMicromechanics model incorporating with molecular dynamics (MD) simulation is developed to simulate the frictional behavior of carbon nanotube (CNT) arrays in ceramic nanocomposites. MD model is used to compute the interaction force and simulate failure mechanisms of individual nanotube at atomic length scale. The force and deformation calculated from MD simulation are passed to the continuum model to simulate the interaction between nanotube arrays and AFM tips. The coefficient of friction is determined at different load levels. The simulation shows that the low friction in the thick-wall CNT systems occurs because the stiffer CNTs are more resistant to collapse under the applied loads. The predictions for the coefficient of friction are consistent with nanoscale tests.

Observation of Water Behavior in the Contact Area between Porous Rubber and a Mating Surface during Sliding

2012 ◽  
Vol 40 (3) ◽  
pp. 186-200
Author(s):  
Yusuke Minami ◽  
Tomoaki Iwai ◽  
Yutaka Shoukaku
Keyword(s):  
Water Flow ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Real Contact Area ◽  
The Real ◽  
Air Bubble ◽  
Real Contact ◽  
Rear Edge ◽  
The Coefficient Of Friction ◽  
Dove Prism

ABSTRACT Porous rubber is often used as the tread rubber of studless tires because of its higher coefficient of friction on icy surfaces, as the real contact area is larger because of its lower elastic modulus. It is said that the real contact area increases owing to the water absorption into the pores. The purpose of this study was to clarify the effect of pores on the surface of porous rubber during sliding under wet conditions. In this experiment, porous rubber was rubbed with a dove prism under wet conditions, so as to measure the coefficient of friction in concurrence with observing the friction surface. The total internal reflection method was adopted to distinguish the real contact area from the wet contact area. The real contact area was observed as a black area in captured image. Particle-tracking velocimetry was also conducted to visualize the water flow in the vicinity of pores during the sliding. The results of this study show that the absorption of water into the pores was not observed. The pore contained an air bubble during the sliding. The water flow detouring around the air bubble in the pore was also observed. In regard to contact, the front edge of the pore was not in contact with the mating dove prism. On the other hand, the rear edge of the pore was clearly seen as a black arc even if the pore left the dove prism. Thus, the rear edge of the pore contacting with the dove prism most likely wipes the water, so that the coefficient of friction of rubber with the pore was higher than that without the pore.

On the Mechanics of Crack Initiation and Propagation in Elasto-Plastic Materials in Impact Fretting Wear

2004 ◽  
Vol 126 (2) ◽  
pp. 395-403 ◽  
Author(s):  
Y. B. Gessesse ◽  
M. H. Attia
Keyword(s):  
Crack Initiation ◽  
Contact Pressure ◽  
Coefficient Of Friction ◽  
Contact Area ◽  
Plastic Material ◽  
Oblique Impact ◽  
Fretting Wear ◽  
Isotropic Hardening ◽  
Friction Forces ◽  
The Coefficient Of Friction

Normal and oblique impact wear processes are characterized by unique features, which include the development of some residual stress components that vanish in unidirectional sliding. Parametric finite element analyses were conducted to estimate the likelihood locations for crack initiation, and the subsequent direction and rate of crack propagation in an elasto-plastic material with bi-linear isotropic hardening properties. The results showed that the increase in contact pressure can cause a significant increase in the size of the plastically deformed crack initiation zone and allows it to reach the surface. Such behavior is not predicted under continuous sliding conditions. The presence of surface friction forces in oblique impact, can also result in the development of a secondary region of high tensile stresses at the contact area. Using the crack tip slip displacement CTSD method, the rate of crack growth was found to be linearly proportional to the crack length, and significantly dependent on the contact pressure and the coefficient of friction at the crack surface. The small effect of the coefficient of friction at the micro-contact area on wear suggests that the effect of shear traction is mainly due to the increase in the depth of the crack nucleation zone. As expected, the increase of the material flow stress with strain-hardening has a wear reducing effect.

scholarly journals Achieving Ultra-Low Friction with Diamond/Metal Systems in Extreme Environments

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3791
Author(s):  
Pantcho Stoyanov ◽  
Rolf Merz ◽  
Markus Stricker ◽  
Michael Kopnarski ◽  
Martin Dienwiebel
Keyword(s):  
Coefficient Of Friction ◽  
Wear Track ◽  
High Vacuum ◽  
Extreme Environments ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Low Friction ◽  
The Coefficient Of Friction ◽  
On Line ◽  
Low Wear

In the search for achieving ultra-low friction for applications in extreme environments, we evaluate the interfacial processes of diamond/tungsten sliding contacts using an on-line macro-tribometer and a micro-tribometer in an ultra-high vacuum. The coefficient of friction for the tests with the on-line tribometer remained considerably low for unlubricated sliding of tungsten, which correlated well with the relatively low wear rates and low roughness on the wear track throughout the sliding. Ex situ analysis was performed by means of XPS and SEM-FIB in order to better understand the underlying mechanisms of low friction and low-wear sliding. The analysis did not reveal any evidence of tribofilm or transferfilm formation on the counterface, indicating the absence of significant bonding between the diamond and tungsten surfaces, which correlated well with the low-friction values. The minimal adhesive interaction and material transfer can possibly be explained by the low initial roughness values as well as high cohesive bonding energies of the two materials. The appearance of the wear track as well as the relatively higher roughness perpendicular to the sliding indicated that abrasion was the main wear mechanism. In order to elucidate the low friction of this tribocouple, we performed micro-tribological experiments in ultra-high vacuum conditions. The results show that the friction coefficient was reduced significantly in UHV. In addition, subsequently to baking the chamber, the coefficient of friction approached ultra-low values. Based on the results obtained in this study, the diamond/tungsten tribocouple seems promising for tribological interfaces in spacecraft systems, which can improve the durability of the components.

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