Analysis of elastic contact due to meniscus adhesion force

Ono, Kyosuke

doi:10.1299/transjsme.14-00673

Cited by 3 publications

(2 citation statements)

References 34 publications

(6 reference statements)

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“…A solution such that r s ≤ 0 means that there is no solid contact, so Equation (24) with zero contact pressure is used to solve for the meniscus radius r using the NR method. Although φ should be taken into account when the sphere radius is small, the calculated results when φ = 0 have been described in [56]. Because the calculation error is small for R = 2 mm, the results of the meniscus contact solutions for the case R = 2 mm are used for a better understanding of the experiments.…”

Section: Elastic Contact Characteristics Due To Meniscus Formationmentioning

confidence: 99%

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Ono

2024

Lubricants

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This review presents a series of studies which have demonstrated that the diffusion characteristics of rarefied mobile lubricant films used in modern magnetic disks can be evaluated by a novel diffusion theory based on continuum mechanics, and that the meniscus force of the rarefied film is the major interaction force at the head-disk interface. The limitations of the conventional diffusion and disjoining pressure equations are first shown, and diffusion and disjoining pressure equations for rarefied liquid films are proposed, showing that the diffusion coefficient is in good agreement with the experiment. The experiment, in which glass spheres with radii of 1 and 2 mm collided with magnetic disks of different film thicknesses, showed that attraction similar to the pull-off forces of a static meniscus was measured only at the separation. Furthermore, mathematical analysis of the elastic meniscus contact between a sphere and a plane with a submonolayer liquid film showed that the maximum adhesion force is equal to the meniscus pull-off force and that the contact characteristics become similar to those of the JKR theory as the liquid film thickness decreases. A basic physical model of submonolayer liquid film is also proposed to justify the continuum mathematical equations.

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Section: Elastic Contact Characteristics Due To Meniscus Formationmentioning

confidence: 99%

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Ono

2024

Lubricants

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“…The gap between the head surface and the contacting asperity at the periphery of the meniscus is more than 2T ml at the instant of meniscus formation, and the gap will become larger than 1 nm because of the additional effect of lubricant inflow generated from the difference of the Laplace pressure and disjoining pressure [26]. This suggests that the surface force due to the surface energy from the area outside the meniscus can be negligibly small.…”

Section: Surface Force Models and Assumptions For Numerical Analysismentioning

confidence: 99%

Numerical Analysis of Surface Force of Diamond-Like Carbon Surface Coated with Monolayer Lubricant Film

Ono

2018

Tribology Online

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Diamond-like carbon (DLC) is widely used as a hard, protective layer with a relatively low surface energy. In the head-disk interface in magnetic disk drives, however, the DLC layer is coated with a monolayer perfluoropolyether lubricant with a high bond ratio to avoid DLC-DLC contact and to secure head/disk wear reliability. In this study, we theoretically analyzed the effect of lubricant thickness and bond ratio on the adhesion force between the head-disk interface (HDI) in a mono/submono-layer thickness regime. It was found that the adhesion force had the lowest sensitivity to lubricant thickness variations at a 0.85 bond ratio. In addition, the maximum adhesion force was minimized when the lubricant thickness was ~0.6 nm for the measured parameter values of the HDI. This suggests that the current lubricant thickness of 1.0-1.2 nm can be reduced to 0.6 nm, accompanied by a slight decrease in the adhesion force and a slight increase in the resistance against any variation in its thickness. This tribo-surface-modification concept can be applied to surfacemodification coatings in other fields such as micro/nano-electromechanical systems. The compatibility of the theoretical surface energy function with experimental data indicates the validity and consistency of this theory.

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Analysis of Microwaviness-Excited Vibrations of a Flying Head Slider in Proximity and Asperity Contact Regimes

Ono

2017

Journal of Tribology

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The vibration characteristics of a thermal fly-height control (TFC) head slider in the proximity and asperity contact regimes attract much attention, because the head–disk spacing (HDS) must be less than 1 nm in order to increase the recording density in hard disk drives. This paper presents a numerical analysis of the microwaviness (MW)-excited vibrations in the flying head slider during the touchdown (TD) process. We first formulate the total force applied to the TFC head slider as a function of the HDS, based on rough-surface adhesion contact models and an air-bearing force model. Then, the MW-excited vibrations of a single-degree-of-freedom (DOF) slider model at TD are simulated by the Runge–Kutta method. It is found that, when the MW amplitude is less than the spacing range of static instability in the total force, the slider jumps to a contact state from a near-contact or mobile-lubricant-contact state. It then jumps to a flying state even when the head surface is protruded further by increasing the TFC power. When the MW amplitude is relatively large, a drastically large spacing variation that contains a wide range of frequency components below 100 kHz appears in the static unstable region. These calculated results can clarify the mechanisms behind a few peculiar experimental phenomena reported in the past.

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Analysis of elastic contact due to meniscus adhesion force

Cited by 3 publications

References 34 publications

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Physics of the Sub-Monolayer Lubricant in the Head-Disk Interface

Numerical Analysis of Surface Force of Diamond-Like Carbon Surface Coated with Monolayer Lubricant Film

Analysis of Microwaviness-Excited Vibrations of a Flying Head Slider in Proximity and Asperity Contact Regimes

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