Wear Characteristics of Carbon-Coated Magnetic Rigid Disks With Well-Defined Surface Texture

1993 ◽  
Vol 115 (4) ◽  
pp. 573-577 ◽  
Author(s):  
Hideaki Tanaka ◽  
Katsuhiko Shiota ◽  
Kenichi Gomi ◽  
Yoshihiko Miyake
Keyword(s):  
Surface Texture ◽  
Disk Surface ◽  
Wear Depth ◽  
Carbon Overcoat ◽  
Surface Textures ◽  
Wear Characteristics ◽  
Apparent Area ◽  
Rigid Disks ◽  
Carbon Coated ◽  
Lithography Technique

Wear characteristics are described for carbon-coated magnetic rigid disks with well-defined surface textures. Concentric circular hills with uniform height (ca. 80 nm) are produced on a disk surface using a photo-lithography technique, to control the apparent area of contact with a slider. Wear depth on the order of nanometers of the carbon overcoat is evaluated from the decrease in hill height after a drag test. Wear depth increases proportionally with the increase in average contact pressure, which is calculated from the load and apparent area of contact between the disk and slider. Lubricant diminishes wear of the carbon overcoat approximately 50 percent compared with that of an unlubricated overcoat.

Lubricant Performance in Magnetic Thin Film Disks With Carbon Overcoat—Part II: Durability

1991 ◽  
Vol 113 (1) ◽  
pp. 32-37 ◽  
Author(s):  
J. L. Streator ◽  
B. Bhushan ◽  
D. B. Bogy
Keyword(s):  
Thin Film ◽  
Disk Surface ◽  
Low Friction ◽  
Carbon Overcoat ◽  
Liquid Lubricant ◽  
Carbon Coated ◽  
Friction Measurements ◽  
Lubricant Performance ◽  
Lubricant Viscosity ◽  
Pfpe Lubricants

Several perfluoropolyether (PFPE) lubricants are evaluated in terms of their ability to maintain low friction and resist wear. The lubricants tested include three nonpolar liquid lubricants and one polar liquid lubricant. Dynamic friction measurements are presented for an IBM 3380-type slider in contact with 130 mm carbon-coated thin film disks. Disk surface run-in and disk durability are evaluated by monitoring the friction force during constant speed sliding. Disk run-in is presented as a function of lubricant thickness and sliding speed, while disk durability is determined for different disk topographies and lubricant thicknesses. It was found that lubricant viscosity was well correlated with the amount of disk run-in and the number of sliding cycles until disk failure. It is proposed that the greater wear durability of the less viscous lubricants can be attributed to their greater mobility on the disk surface.

Flying Stiction, Lubricant Pick-Up and Carbon-Overcoat Wear of Magnetic Heads

1999 ◽  
Vol 121 (1) ◽  
pp. 97-101 ◽  
Author(s):  
Chao Gao ◽  
Peihua Dai ◽  
Vinh Vu
Keyword(s):  
Fold Increase ◽  
Static Friction ◽  
Disk Surface ◽  
Exponential Dependence ◽  
Magnetic Head ◽  
Bearing Surface ◽  
Lubricant Thickness ◽  
Carbon Overcoat ◽  
Carbon Coated ◽  
Secondary Ion

Flying stiction, a high static friction force resulting from a magnetic head seeking/flying over a disk surface, has posed a new challenge in magnetic-disk tribology for low flying heights (˜30 nm or less), as demanded by high recording densities. Two types of magnetic heads were used in this study. A more than 10-fold increase in flying stiction force was observed for the carbon coated heads after a 24 hours of seeking/flying over the disk surface. Using Time of Flight Secondary Ion Mass Spectroscopy and a scanning micro-ellipsometer, we found that the lubricant pickup during seeking/flying operation was responsible for the observed 10-fold increase of the flying stiction force. A nearly exponential dependence of flying stiction force on lubricant amount picked up on the air bearing surface (ABS) of the magnetic heads was found. For 24 hours of seeking/flying time, the lubricant accumulated on the ABS surfaces can be up to 1.5 nm, comparable to the lubricant thickness on the disk surfaces. The lubricant amount was found quite uniformly distributed over the ABS surface of the head. Wear on the carbon overcoat of the magnetic heads was also measured, and was equivalent to approximately 1 nm carbon loss for a 24-hour seeking/flying period. The wear rate of the carbon overcoat was very fast for short periods of seeking time (˜2 hours) and slowed down to near-zero as lubricant built up on the ABS surface, indicating that the lubricant on the head protected carbon wear. The wear of carbon overcoat strongly suggests that intermittent physical contacts between the disk surface and head ABS occurred during seeking/flying operations.

Wear Characteristics of Conventional and Squeeze-Film Artificial Hip Joints

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
S. Boedo ◽  
S. A. Coots
Keyword(s):  
Implant Design ◽  
Squeeze Film ◽  
Linear Wear ◽  
Wear Depth ◽  
Element Analysis ◽  
Wear Characteristics ◽  
Wear Rates ◽  
Cycle Loading ◽  
Artificial Hip Joints ◽  
Elastic Elements

This paper investigates the wear characteristics of a novel squeeze-film hip implant design. Key features of the design are elastic elements attached to the cup which provide a mechanical means for ball separation during the swing phase of the gait loading cycle. An Archard-based wear formulation was implemented utilizing the ansys finite element analysis program which relates contact pressure and sliding distance to linear wear depth. It is found that low-modulus elastic elements with bonded high-modulus metal coatings offer significant predicted improvement in linear and volumetric wear rates when compared with conventional implant geometries for gait cycle loading and kinematic conditions found in practice.

scholarly journals Comparison of the Influences of Surface Texture and Boundary Slip on Tribological Performances

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Qiyin Lin ◽  
Baotong Li
Keyword(s):  
Surface Texture ◽  
Slip Velocity ◽  
Structure Parameters ◽  
Textured Surfaces ◽  
Slider Bearing ◽  
Boundary Slip ◽  
Surface Textures ◽  
Slip Surfaces ◽  
Texture Structure ◽  
The Relationship

Close attentions have been widely paid to the engineering textured and slip surfaces for improving bearing tribological performances. Comparison studies on the tribological characteristics of slip and textured surfaces are carried out in this work. The analysis results point out that the influences of surface texture and boundary slip on tribological performances of slider bearing are strongly similar. For the determinate surface textures, there is one and only value of slip velocity to make the tribological performances of textured and slip surfaces in agreement. The corresponding relation between the slip velocity and the texture structure parameters is also obtained, and the size of slip velocity is directly related to the texture geometry parameters including its position parameters. This study will help us to further understand the relationship between boundary slip and surface texture and also the slip phenomenon.

scholarly journals The Development of Surface Roughness and Implications for Cellular Attachment in Biomedical Applications

2001 ◽  
Vol 705 ◽  
Author(s):  
Bruce Banks ◽  
Sharon Miller ◽  
Kim de Groh ◽  
Amy Chan ◽  
Mandeep Sahota
Keyword(s):  
Surface Roughness ◽  
Computational Modeling ◽  
Surface Texture ◽  
Atomic Oxygen ◽  
Treatment Time ◽  
Ion Beam ◽  
Cleveland Clinic ◽  
Surface Textures ◽  
Grit Blasting ◽  
Cellular Attachment

AbstractThe application of a microscopic surface texture produced by ion beam sputter texturing to the surfaces of polymer implants has been shown to result in significant increases in cellular attachment compared to smooth surface implants in animal studies. A collaborative program between NASA Glenn Research Center and the Cleveland Clinic Foundation has been established to evaluate the potential for improving osteoblast attachment to surfaces that have been microscopically roughened by atomic oxygen texturing. The range of surface textures that is feasible depends upon both the texturing process and the duration of treatment. To determine whether surface texture saturates or continues to increase with treatment duration, an effort was conducted to examine the development of surface textures produced by various physical and chemical erosion processes. Both experimental tests and computational modeling were performed to explore the growth of surface texture with treatment time. Surface texturing by means of abrasive grit blasting of glass, stainless steel and polymethylmethacrylate surfaces was examined to measure the growth in roughness with grit blasting duration by surface profilometry measurements. Laboratory tests and computational modeling was also conducted to examine the development of texture on Aclar® (chlorotrifluoroethylene) and Kapton® polyimide, respectively. For the atomic oxygen texturing tests of Aclar®, atomic force microscopy was used to measure the development of texture with atomic oxygen fluence. The results of all the testing and computational modeling support the premise that development of surface roughness obeys Poisson statistics. The results indicate that surface roughness does not saturate but increases as the square root of the treatment time.

Strain Induced Inward Grain Growth during Recrystallisation in Steel Sheets with BCC Crystal Structure

2012 ◽  
Vol 715-716 ◽  
pp. 303-308
Author(s):  
Jai Gautam ◽  
Roumen H. Petrov ◽  
Elke Leunis ◽  
Leo Kestens
Keyword(s):  
Surface Texture ◽  
Boundary Migration ◽  
Annealing Treatment ◽  
Random Surface ◽  
Surface Textures ◽  
Steel Sheets ◽  
Α Phase ◽  
Migration Mechanism ◽  
Different Types ◽  
Goss Orientation

The present paper investigates the potential application of Strain Induced Boundary Migration mechanism on the two different types of surface textures developed after α-γ-α phase transformation annealing, one with preferred cube and Goss orientation at the surface and the other with random surface texture without preferred orientations. It has been demonstrated that these surface texture components grow in across the thickness of the sheet after an appropriate combinations of a critical amount of rolling reductions and an annealing treatment at the recrystallisation temperature.

Study of Tribochemical Processes on Hard Disks Using Photoemission Electron Microscopy

1999 ◽  
Vol 121 (4) ◽  
pp. 961-967 ◽  
Author(s):  
Simone Anders ◽  
Thomas Stammler ◽  
Walton Fong ◽  
Chao-Yuan Chen ◽  
David B. Bogy ◽  
...  
Keyword(s):  
Hard Disks ◽  
Chemical Modifications ◽  
Hard Carbon ◽  
Carbon Overcoat ◽  
Chemical Changes ◽  
X Ray ◽  
Tribochemical Processes ◽  
Carbon Coated ◽  
Photoemission Electron ◽  
Wear Tests

The interface between hard disk and slider involves mechanical and tribochemical processes between the hard carbon overcoat of the disk, the lubricant, and the carbon coated or uncoated slider surface. These processes have been studied by two related X-ray techniques—Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy and Photoemission Electron Microscopy (PEEM) using X-rays. NEXAFS allows studying the elemented composition and chemical bonding in a material, whereas PEEM combines this ability with imaging of the sample. Lubricated and unlubricated disks were worn under various conditions using carbon coated and uncoated sliders. The wear tracks on the hard disks were investigated using PEEM to find chemical and elemental changes caused by the wear. Local NEXAFS spectra taken in wear tracks using the PEEM microscope show no chemical changes on unlubricated disks, just a reduction of the hard carbon overcoat thickness. On lubricated disks remarkable chemical modifications of the lubricants caused by the wear are observed if the disks failed the wear tests. The chemical changes are manifested in a formation of various new carbon-oxygen (mostly carboxylic) bonds in the wear tracks and in a strong reduction of the amount of fluorine and carbon. The chemical modifications were only found inside the wear tracks and are clearly caused by the wear. It was found that lubricant degradation is not solely a mechanical process of molecule scission but accompanied by oxidation reactions. The chemical changes were strongly correlated to the tribological behavior of the disks: the worse the disks performed in the wear tests, the stronger were the chemical modifications.

THE EFFECT OF SURFACE TEXTURE OF STEEL DISC ON FRICTION AND FRETTING WEAR

Tribologia ◽  
2018 ◽  
Vol 280 (4) ◽  
pp. 39-48 ◽  
Author(s):  
Agnieszka LENART ◽  
Paweł PAWLUS ◽  
Andrzej DZIERWA ◽  
Mirosław TUPAJ
Keyword(s):  
Relative Humidity ◽  
Surface Texture ◽  
Normal Load ◽  
Fretting Wear ◽  
Surface Textures ◽  
Steel Disc ◽  
42Crmo4 Steel ◽  
Number Of Cycles ◽  
Effect Of Surface

Fretting tests were performed using an Optimol SRV5 tribotester in a ball-on-flat scheme. Balls from 100Cr6 steel of 60 HRC hardness and diameters of 10 mm co-acted with discs from 42CrMo4 steel of 47 HRC hardness under dry gross fretting conditions. Tests were performed at 300C and 25–35% relative humidity, and the number of cycles was 18000. During each test, the normal load was kept constant. Six sets of experiments were conducted. Discs had different surface textures as the result of machining. It was found that the lowest coefficients of friction were obtained for anisotropic surfaces when ball movements were perpendicular to main disc texture directions.

scholarly journals Image Scale Estimation Using Surface Textures for Quantitative Visual Inspection

2021 ◽  
Vol 6 (1) ◽  
pp. 1-3
Author(s):  
Juan Park ◽  
Chul Min Yeum ◽  
Trevor Hrynyk
Keyword(s):  
Neural Network ◽  
Regression Model ◽  
Convolutional Neural Network ◽  
Surface Texture ◽  
Visual Inspection ◽  
Estimation Error ◽  
Estimation Technique ◽  
Surface Textures ◽  
Scale Estimation ◽  
Using Data

In this study, a learning-based scale estimation technique is proposed to enable quantitative evaluation of inspection regions. The underlying idea is that surface texture of structures (i.e. bridges or buildings) captured on images contains the scale information of the corresponding images, which is represented by pixel per physical dimension (e.g., mm, inch). This allows training a regression model that provides a relationship between surface textures on images and their corresponding scales. Deep convolutional neural network is used to extract scale-related features from the texture patches and estimate their scales. The trained model can be exploited to estimate scales for all images captured from structure surfaces that have similar textures. The capability of the proposed technique is fully demonstrated using data collected from surface textures of three different structures and achieves an overall average scale estimation error of less than 15%.

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