Effects of ultra-thin liquid lubricant films on contact slider dynamics in hard-disk drives

2007 ◽  
Vol 40 (5) ◽  
pp. 770-779 ◽  
Author(s):  
Norio Tagawa ◽  
Yoshiaki Tashiro ◽  
Atsunobu Mori
Keyword(s):  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drives ◽  
Liquid Lubricant ◽  
Lubricant Films ◽  
Contact Slider

Effects of End Groups on the Spreading Characteristics of Molecularly Thin Liquid Lubricant Films in Hard Disk Drives

2007 ◽  
Vol 43 (9) ◽  
pp. 3705-3709 ◽  
Author(s):  
N. Tagawa ◽  
M. Korenaga ◽  
A. Mori ◽  
N. Kobayashi ◽  
M. Ikegami
Keyword(s):  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drives ◽  
Liquid Lubricant ◽  
End Groups ◽  
Lubricant Films

Effect of Temperature on the Spreading Characteristics of Molecularly Thin Liquid Lubricant Films in Hard Disk Drives

2008 ◽  
Author(s):  
Norio Tagawa ◽  
Kenta Mori ◽  
Atsunobu Mori ◽  
Masako Ikegami
Keyword(s):  
Diffusion Coefficient ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Effect Of Temperature ◽  
Disk Drives ◽  
Liquid Lubricant ◽  
Quantitative Correlation ◽  
Lubricant Films ◽  
Apparent Diffusion ◽  
Mobile Fraction

In this study, the effect of temperature on the spreading characteristics of ultra-thin liquid lubricant films in hard disk drives (HDD) was investigated by using three types of lubricants, namely, Zdol2000, Ztetraol2000, and A20H2000. The apparent diffusion coefficient of individual lubricants was evaluated and compared by varying the temperature of disk substrates. As a result, it was found that the mobility of each lubricant increases with the temperature. However, the rate of mobility increase is different for each lubricant, depending on the lubricant material. Furthermore, there exists no quantitative correlation between the mobility increase for ultra-thin liquid lubricant films and the viscosity decrease in bulk lubricant materials due to a rise in the temperature. It was also found that among the test lubricants, A20H2000 has the highest robustness for temperature change. In addition, it could be observed that the evaporation of the mobile fraction of lubricants occurred remarkably over a temperature range of 50– 80 °C.

Effects of Molecularly Thin Lubricant Films on Slider Touch-Down and Take-Off Hysteresis Behavior in Hard Disk Drives

2005 ◽  
Author(s):  
Norio Tagawa ◽  
Hiroshi Sendo ◽  
Atsunobu Mori
Keyword(s):  
Molecular Weight ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Lubricant Film ◽  
Disk Drives ◽  
Hysteresis Behavior ◽  
Liquid Lubricant ◽  
Pfpe Lubricant ◽  
Lubricant Films ◽  
The Difference

This paper describes the effects of molecularly thin liquid lubricant films on slider hysteresis phenomena of touch-down and take-off process in hard disk drives. In the experiments, the tested lubricants were conventional Zdol and novel cyclotriphosphazene-terminated PFPE lubricant (A20H lubricant) with different molecular weight. As a result, it is found that the difference between the touch-down velocity and take-off one (hysteresis behavior) for novel A20H lubricant film is larger than that for Zdol. The LDV RMS values for novel lubricant, which indicate the slider bouncing vibration during the slider-lubricant contact, are also larger than that for Zdol. The effects of lubricant film thickness and molecular weight on slider hysteresis behavior as well as slider bouncing vibration are also clarified. In addition, the replenishment performances of test lubricants for depleted tracks due to slider touch down contact are investigated and discussed.

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