Adhesion and Friction Behavior of Magnetic Disks With Ultrathin Perfluoropolyether Lubricant Films Having Different End-Groups Measured Using Pin-on-Disk Test

2013 ◽  
Vol 49 (6) ◽  
pp. 2638-2644 ◽  
Author(s):  
Hiroshi Tani ◽  
Toshiya Mitsutome ◽  
Norio Tagawa
Keyword(s):  
Friction Behavior ◽  
Magnetic Disks ◽  
End Groups ◽  
Lubricant Films ◽  
Perfluoropolyether Lubricant ◽  
Pin On Disk ◽  
Disk Test

scholarly journals Dependence of Pin Surface Roughness for Friction Forces of Ultrathin Perfluoropolyether Lubricant Film on Magnetic Disks by Pin-on-Disk Test

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
H. Tani ◽  
Y. Mitsuya ◽  
T. Kitagawa ◽  
N. Tagawa
Keyword(s):  
Surface Roughness ◽  
Ion Beam ◽  
Lubricant Film ◽  
Friction Forces ◽  
Magnetic Disks ◽  
End Groups ◽  
Cluster Ion ◽  
Perfluoropolyether Lubricant ◽  
Gas Cluster Ion Beam ◽  
Pin On Disk

We fabricated supersmooth probes for use in pin-on-disk sliding tests by applying gas cluster ion beam irradiation to glass convex lenses. In the fabrication process, various changes were made to the irradiation conditions; these included one-step irradiation of Ar clusters or two-step irradiation of Ar and N2clusters, with or without Ar cluster-assisted tough carbon deposition prior to N2irradiation, and the application of various ion doses onto the surface. We successfully obtained probes with a centerline averaged surface roughness that ranged widely from 1.08 to 4.30 nm. Using these probes, we measured the friction forces exerted on magnetic disks coated with a molecularly thin lubricant film. Perfluoropolyether lubricant films with different numbers of hydroxyl end groups were compared, and our results indicated that the friction force increases as the surface roughness of the pin decreases and that increases as the number of hydroxyl end groups increases.

Effect of TiO2 Addition of Oxidizing Catalytic Activity of an Al2O3 Slider for Magnetic Disks

1994 ◽  
Vol 116 (2) ◽  
pp. 275-279 ◽  
Author(s):  
Shinsuke Higuchi ◽  
Takeshi Miyazaki ◽  
Yasutaka Suzuki ◽  
Hideaki Tanaka ◽  
Iwao Matsuyama
Keyword(s):  
Catalytic Activity ◽  
Grain Boundary ◽  
Test System ◽  
High Catalytic Activity ◽  
Carbon Overcoat ◽  
Magnetic Disks ◽  
Tio2 Addition ◽  
Pin On Disk ◽  
Tio2 Phase ◽  
Disk Test

Oxidizing catalytic activity of a slider is a factor which could affect wear of magnetic disks with a carbon overcoat. Al2O3 composites containing 2–50 mol% TiO2 were produced, which had different oxidizing catalytic activities but nearly the same hardness and thermal conductivity. Activation energy (Ec) for carbon oxidation when it is mixed with the composite was measured to get the oxidizing catalytic activity, and it was found that Ec changed from about 70 kJ/mol for Al2O3 to about 110 kJ/mol for Al2O3 containing 9.1–16.7 mol% TiO2. TiO2 addition increased and decreased Ec. The former was due to segregation of the Ti-Al-O phase at the Al2O3 grain boundary, which could inhibit the catalysis at the Al2O3 grain boundary. The latter was due to the unreacted TiO2 phase, which by itself has high catalytic activity. TiO2-Al2O3 sliders having different Ec were examined in sliding wear against a magnetic disk with a carbon overcoat using a pin-on-disk test system. It was found that wear rate of the carbon overcoat was lower when the slider had a larger Ec, i.e., lower catalytic activity. It was also found that wear particles of the carbon overcoat were likely to be larger with lower catalytic activity.

S162012 Adhesion and Friction Force Measurement of Ultra-thin Liquid Lubricant on Magnetic Disks by Pin-on-Disk test

2012 ◽  
Vol 2012 (0) ◽  
pp. _S162012-1-_S162012-4
Author(s):  
Hiroshi TANI ◽  
Toshiya MITSUTOME ◽  
Yusuke TSUJIGUCHI ◽  
Masayuki KANDA ◽  
Norio TAGAWA
Keyword(s):  
Friction Force ◽  
Force Measurement ◽  
Magnetic Disks ◽  
Liquid Lubricant ◽  
Pin On Disk ◽  
Disk Test

Structural and Tribological Properties of TiC/C/Ag Coatings in Vacuum and Ambient Environments

2001 ◽  
Vol 697 ◽  
Author(s):  
Jose L. Endrino ◽  
Jose J. Nainaparampil ◽  
James E. Krzanowski
Keyword(s):  
Carbon Content ◽  
Laser Energy ◽  
High Vacuum ◽  
Ambient Conditions ◽  
Friction Behavior ◽  
Cross Sectional ◽  
Reduced Modulus ◽  
Custom Made ◽  
Disk Friction ◽  
Pin On Disk

AbstractTiC/C/Ag coatings were deposited by magnetron sputtering pulsed laser deposition (MSPLD) combining sputtering from a custom made Ti-Ag (60:40) target with the ablation of carbon. Energy disperse spectroscopy (EDS) was used to determine the elemental composition, and x-ray diffraction (XRD) and cross-sectional scanning electron microscopy (XSEM) to examine the structure of the films. Hardness and reduced modulus measurements were acquired using a nanoindentation technique. The pin-on-disk friction test was used to study the friction behavior of the deposited samples in high vacuum and ambient conditions. Variations in the laser energy and the power of the sputtering gun yielded a set of samples with carbon content that ranged from 15.0 to 95.6 percent. The hardest samples with the highest reduced modulus were those with a moderate carbon content and that were shown to form a titanium carbide phase. Tribological results indicated that there is an optimum composition of a TiC/C/Ag coating (~25 at.% carbon) for which it can be reversible and provide lubrication in both ambient and vacuum.

Predicting the wear coefficient and friction coefficient in dry point contact using continuum damage mechanics

2018 ◽  
Vol 233 (3) ◽  
pp. 447-455 ◽  
Author(s):  
Sahar Ghatrehsamani ◽  
Saleh Akbarzadeh
Keyword(s):  
Friction Coefficient ◽  
Damage Mechanics ◽  
Point Contact ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Wear Coefficient ◽  
Mechanics Model ◽  
Pin On Disk ◽  
Disk Test ◽  
The Continuum

Wear coefficient and friction coefficient are two of the key parameters in the performance of any tribo-system. The main purpose of the present research is to use continuum damage mechanics to predict wear coefficient. Thus, a contact model is utilized that can be used to obtain the friction coefficient between the contacting surfaces. By applying this model to the continuum damage mechanics model, the wear coefficient between dry surfaces is predicted. One of the advantages of using this model is that the wear coefficient can be numerically predicted unlike other methods which highly rely on experimental data. In order to verify the results predicted by this model, tests were performed using pin-on-disk test rig for several ST37 samples. The results indicated that the wear coefficient increases with increasing the friction coefficient.

Friction-Heating Maps and Their Applications

MRS Bulletin ◽  
1991 ◽  
Vol 16 (10) ◽  
pp. 41-48 ◽  
Author(s):  
H.S. Kong ◽  
M.F. Ashby
Keyword(s):  
Normal Force ◽  
Frictional Heat ◽  
Unified Approach ◽  
Magnetic Disks ◽  
Heat Flows ◽  
Bulk Heating ◽  
Friction Heating ◽  
Image Position ◽  
Pin On Disk ◽  
Nominal Contact Area

Friction is often a nuisance, but it can be useful too. Brakes, clutches, and tires rely on it, of course, though the inevitable fractional heat remains a problem. Other applications use frictional heat: friction cutting and welding, skiing, skating, and curling. The damage to magnetic disks caused by head-disk contact and the striking of matches are also examples.This article illustrates a framework where the thermal aspects of friction can be analyzed in an informative way. It uses a unified approach to the calculation of flash and bulk heating, and a helpful diagram—the frictional temperature map—to display the results. The method is approximate, but the approximations have been carefully chosen and calibrated to give precision adequate to most tasks, and the gain in simplicity is great.The symbols used in this article are defined in Table I.When two contacting solids 1 and 2, pressed together by a normal force F, slide at a relative velocity ν and with coefficient of friction ü, heat is generated at the surface where they meet. The heat generated, q, per unit of nominal contact area, An, per second isThe heat flows into the two solids, partitioned between them in a way that depends on their geometry and thermal properties. Figure 1 shows one geometry commonly used for laboratory tests: the pin-on-disk configuration. The pin is identified by the subscript 1, the disk by subscript 2. Solid 1 can have properties which differ from those of solid 2.

Investigation of wear on the upper edges of webs of thin-film coated single-screw extruders processing pure polymers

2021 ◽  
Vol 63 (2) ◽  
pp. 143-150
Author(s):  
Torben Buttler ◽  
Jens Hamje ◽  
Rolf Reiter ◽  
Volker Wesling
Keyword(s):  
Wear Behavior ◽  
Cold Work ◽  
Polymer Processing ◽  
Chromium Nitride ◽  
Metallographic Examination ◽  
Test Speed ◽  
Single Screw Extruders ◽  
Pin On Disk ◽  
Screw Extruders ◽  
Disk Test

Abstract During polymer extrusion there are a variety of situations in which the screwthread of the extrusion screw has an unlubricated metal-to-metal contact with the barrel wall. At the same time the screw coating is subjected to the highest loads. The combination of a secondary hardening cold work steel 1.2379 and a chromium nitride coating deposited by ARC-PVD, which is frequently used in polymer processing, is characterized and investigated. The characterization is done by metallographic examination, SEM and CLSM. The tests were performed on a pin-on-disk and a pin-roll test rig. Different roughness levels were tested on the pin-on-disk test, where massive differences in wear behavior were found. A hybrid surface structure is proposed to optimize the tribosystem. On the pin-on-disk test stand, rollers made of the same material pairing were tested. The test speed was varied to highlight differences and similarities between the tribological systems. A wear minimization of 50 % was achieved and the similarities between the tribological systems were highlighted. In addition, the investigations led to the development of a new model thesis which provides a reason for the development of stippling on the screw when processing polycarbonate.

Quantification of the Surface Morphology of Lubricant Films With Polar End Groups Using Molecular Dynamics Simulation: Periodic Changes in Morphology Depending on Film Thickness

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Susumu Ogata ◽  
Hedong Zhang ◽  
Kenji Fukuzawa ◽  
Yasunaga Mitsuya
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Surface Morphology ◽  
Film Thickness ◽  
Film Surface ◽  
Dynamics Simulation ◽  
Molecular Probe ◽  
Coarse Grained ◽  
End Groups ◽  
Lubricant Films

Using a coarse-grained molecular dynamics simulation based on the bead-spring polymer model, we reproduced the film distribution of molecularly thin lubricant films with polar end groups coated on the disk surface and quantified the film-surface morphology using a molecular-probe scanning method. We found that the film-surface morphology changed periodically with increasing film thickness. The monolayer of a polar lubricant that entirely covers the solid surface provides a flat lubricant surface by exposing its nonpolar backbone outside of the monolayer. By increasing film thickness, the end beads aggregate to make clusters, and bulges form on the lubricant surface, accompanying an increase in surface roughness. The bulges continue to grow even though the averaged film thickness reaches or exceeds the bilayer thickness. With further increases in film thickness, the clusters start to be uniformly distributed in the lateral direction to clearly form a third layer. As for the formation of fourth and fifth layers, the process is basically the same as that for the second and third layers. Through our calculations of the intermolecular potential field and the intermolecular force field, these values are found to change periodically and are synchronized with the formation of molecule aggregations, which explains the mechanism of forming the layered structure that is inherent to a polar lubricant.

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