Influence of lubricant film on magnetic disks for smear accumulation on head slider surface by laser irradiation

2017 ◽  
Vol 2017 (0) ◽  
pp. S1610104
Author(s):  
Yuki UESARAIE ◽  
Hiroshi TANI ◽  
Renguo LU ◽  
Shinji KOGANEZAWA ◽  
Norio TAGAWA
Keyword(s):  
Laser Irradiation ◽  
Lubricant Film ◽  
Magnetic Disks ◽  
Head Slider ◽  
Slider Surface

scholarly journals Electric-Field-Assisted Dip-Coating for Ultra-Thin PFPE Lubricant Film on Magnetic Disks - Molecular Conformation Change by Electric Field -

2011 ◽  
Vol 6 (1) ◽  
pp. 40-44
Author(s):  
Hiroshi Tani ◽  
Masami Kubota ◽  
Masayuki Kanda ◽  
Motohiro Terao ◽  
Norio Tagawa
Keyword(s):  
Electric Field ◽  
Molecular Conformation ◽  
Dip Coating ◽  
Lubricant Film ◽  
Conformation Change ◽  
Magnetic Disks ◽  
Pfpe Lubricant

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.

scholarly journals Electric Field Assisted Dip-coating Process of Ultra-thin PFPE Lubricant Film on Magnetic Disks

2010 ◽  
Vol 4 (1) ◽  
pp. 397-404 ◽  
Author(s):  
Hiroshi TANI ◽  
Masami KUBOTA ◽  
Masayuki KANDA ◽  
Motohiro TERAO ◽  
Norio TAGAWA
Keyword(s):  
Electric Field ◽  
Dip Coating ◽  
Lubricant Film ◽  
Coating Process ◽  
Magnetic Disks ◽  
Pfpe Lubricant

Comparisons of Friction Characteristics of a Lightly Loaded Pin Sliding Over Magnetic Disks Coated With Polar and Non-Polar PFPE Lubricants

2005 ◽  
Author(s):  
Yinbo He ◽  
Yasunaga Mitsuya ◽  
Hedong Zhang ◽  
Kenji Fukuzawa
Keyword(s):  
Friction Force ◽  
Gradual Increase ◽  
Rotating Disk ◽  
Disk Surface ◽  
Lubricant Film ◽  
Magnetic Disks ◽  
Friction Tester ◽  
Pin On Disk ◽  
End Group ◽  
Pfpe Lubricants

This paper deals with the measurement of friction force exerted on molecularly thin lubricant film surfaces using a specially arranged pin-on-disk type friction tester. The measurements were carried out by sliding a 1.5-mm-diameter glass ball slider on a rotating disk surface with small loading force. Polar and non-polar PFPE lubricants were dip-coated on magnetic disks covered with diamond-like-carbon (DLC) film. Lubricant film thickness was varied to constitute multiple layered film structures on the DLC surface. To clarify the stratified effect of thin lubricant film on friction, a lightly loading force and a slow rotational speed were selected. The tested results showed that the friction force on non-polar lubricant surfaces increase slightly for mono-layer and multi-layer cases, while the friction force on polar lubricants show steady and gradual increase with increasing loading force. We conclude that friction force at small loading force is dependent intimately on the thickness, molecular weight and end-group functionality.

Derivation of Rarefaction-Modified Reynolds Equation Considering Porosity of Thin Lubricant Film

1997 ◽  
Vol 119 (4) ◽  
pp. 653-659 ◽  
Author(s):  
Yasunaga Mitsuya ◽  
Zhisheng Deng ◽  
Masahiro Ohka
Keyword(s):  
Reynolds Equation ◽  
Lubricant Film ◽  
The Other ◽  
Magnetic Head ◽  
Permeable Material ◽  
Magnetic Medium ◽  
Magnetic Disk ◽  
Head Slider ◽  
Liquid Lubricant ◽  
Modified Reynolds Equation

A new lubrication model is derived for solving ultra-thin gas lubrication problems encountered in the analysis of a magnetic head slider flying over a magnetic disk coated with giant-molecule lubricant film. In this model, the liquid lubricant film is replaced with a permeable material, and the boundary between the gas and liquid is subject to two kinds of velocity slippage: one due to the rarefaction effect and the other to the porous effect. Using this model, a rarefaction-modified Reynolds equation is derived considering the permeability of the running surface. This equation is then applied to the lubrication of head sliders flying over a magnetic medium. An interesting condition is found to arise wherein total apparent slippage seems to disappear due to the cancellation of the two slippages and the permeability effects are larger for a slider having a steeper pressure gradient.

Electric-Field-Assisted Dip Coating Process of Ultrathin PFPE Lubricant Film for Magnetic Disks

2009 ◽  
Vol 45 (10) ◽  
pp. 3636-3639 ◽  
Author(s):  
H. Tani ◽  
M. Kubota ◽  
M. Kanda ◽  
M. Terao ◽  
N. Tagawa
Keyword(s):  
Electric Field ◽  
Dip Coating ◽  
Lubricant Film ◽  
Coating Process ◽  
Magnetic Disks ◽  
Pfpe Lubricant

Dynamic Analysis of the Rarefaction-Modified Reynolds Equation Considering Porosity of Thin Liquid Lubricant Film

1999 ◽  
Vol 121 (4) ◽  
pp. 864-871 ◽  
Author(s):  
Yasunaga Mitsuya ◽  
Zhisheng Deng ◽  
Masahiro Ohka
Keyword(s):  
Reynolds Equation ◽  
Mean Free Path ◽  
Lubricant Film ◽  
Correction Coefficient ◽  
Dynamic Problems ◽  
Head Slider ◽  
Liquid Lubricant ◽  
Damping Coefficients ◽  
Modified Reynolds Equation ◽  
Velocity Region

A rarefaction-modified Reynolds equation was derived to solve dynamic problems of a thin liquid lubricant film coated on a sliding surface. Applying the perturbation method, a calculation procedure based on FEM was formulated to obtain the stiffnesses and damping coefficients of gas lubricating films over a permeable liquid lubricant. Calculations were performed for a specified flying head slider. First, the effects of the permeability and porosity correction coefficients, which serve to increase the molecular mean free path, were presented focusing on landing on/off characteristics. Next, the effects of those on the stiffnesses and damping coefficients were demonstrated using the frequency domain. The results showed that the permeability and porosity correction coefficient increasingly had an influence on the landing on/off characteristics more in the higher velocity region, and that the permeability was effective in increasing the damping of lubricating films.

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