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

Tani, Hiroshi; Mitsutome, Toshiya; Tagawa, Norio

doi:10.1109/tmag.2013.2253451

Cited by 19 publications

(27 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The relatively larger zero-load friction force for the lower molecular weight D-4OH is attributed to its larger molecular polarity [13,14]. and 1500, respectively.…”

Section: Resultsmentioning

confidence: 95%

PFPE Lubricant Molecular Weight Effects on Slider-Disk Interactions

et al. 2014

View full text Add to dashboard Cite

Slider wear is investigated as a function of D-4OH lubricant film thickness and molecular weight. Slider wear increases with decreasing lubricant film thickness and with increasing molecular weight when compared at the same film thickness in the submonolayer film thickness regime. The two sets of observations are readily interpreted on the basis of the monolayer fraction which corrects the film thickness for the molecular weight-dependent surface coverage.

show abstract

“…The relatively larger zero-load friction force for the lower molecular weight D-4OH is attributed to its larger molecular polarity [13,14]. and 1500, respectively.…”

Section: Resultsmentioning

confidence: 95%

PFPE Lubricant Molecular Weight Effects on Slider-Disk Interactions

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Therefore, the following analysis was performed using the relationship between the load and the frictional force. The contact between a plane and spherical surfaces has been discussed at length in the Johnson-Kendall-Roberts (JKR) theory [8,[11][12][13] considering the force of adhesion. If the load is, W 0 the adhesive force acting between the spherical and plane surfaces is W a , the radius of curvature of the spherical surface is R, and the adhesive energy between the spherical and plane surfaces is γ.…”

Section: Resultsmentioning

confidence: 99%

Thermal Behavior of Frictional Properties on Ultra-Thin Perfluoropolyether Lubricant Film

2016

Self Cite

View full text Add to dashboard Cite

We investigate the thermal behavior of the friction property of ultra-thin perfluoropolyether (PFPE) lubricant film on diamond-like carbon (DLC) overcoats of magnetic disks. We use a newly developed pin-on-disk tester with laser irradiation heating. Results show that the friction coefficient of a lubricated DLC surface with Z-tetraol decreased with increased temperature, while for lubricated disks with Z-03, it gradually decreased at around 120°C and increased over 120°C. This minimal point may indicate the transition temperature. The friction coefficient of both lubricant films on the DLC surface varied with the kinematic viscosity of the lubricant materials, and decreasing the kinematic viscosity decreased the friction coefficient.

show abstract

“…Here γ 0 is the surface energy of bulk lubricant and A* is an effective Hamaker constant [25][26][27]. Waltman et al [26] evaluated the effective Hamaker constant of Z-Tetraol (molecular weight is 2000) to be 1.9 × 10 −19 J and used this value in [18].…”

Section: Calculated Diffusion Coefficients and Comparison With Experimentioning

confidence: 99%

“…Waltman et al [26] evaluated the effective Hamaker constant of Z-Tetraol (molecular weight is 2000) to be 1.9 × 10 −19 J and used this value in [18]. On the other hand, Tani et al [27] experimentally evaluated A* to be 4.8 × 10 −19 J. Therefore, the bulk viscosities were calculated for the Hamaker constant values of 0.47 × 10 −19 and 1.9 × 10 −19 J in Table 1.…”

Section: Calculated Diffusion Coefficients and Comparison With Experimentioning

confidence: 99%

“…Therefore, the bulk viscosities were calculated for the Hamaker constant values of 0.47 × 10 −19 and 1.9 × 10 −19 J in Table 1. The effect of polar surface energy on diffusion coefficient function was ignored here because it seemed to have a minor effect compared with the dispersive component, particularly on disjoining pressure [26,27].…”

Section: Calculated Diffusion Coefficients and Comparison With Experimentioning

confidence: 99%

See 1 more Smart Citation

Disjoining Pressure Derived from the Lennard–Jones Potential, Diffusion Equation, and Diffusion Coefficient for Submonolayer Liquid Film

Ono

2018

Surfaces

View full text Add to dashboard Cite

In magnetic hard disk drives, it is important to evaluate the replenishment effect of a submonolayer lubricant film under a more severe condition that the head–disk spacing has to be reduced from the current 0.7 nm to ~0.5 nm. In contrast to the prevailing conventional diffusion equation validated for multilayer liquid film, the author has already proposed a new diffusion equation more suitable for submonolayer film by intuitively incorporating the density reduction effect in the submonolayer liquid film. This paper presents a rigorous derivation of the disjoining pressure (DP) from Lennard–Jones potential (LJP) and formulated the diffusion equation incorporating the DP. The difference in the rigorous DP and diffusion equation from the previous versions is negligibly small except in a small film thickness less than the van der Waals (vdW) distance. The theoretical relationship between the vdW distance in the DP and the molecular force equilibrium distance in the LJP is elucidated. Rigorous derivations of the DP and diffusion equation for multilayer liquid film from the LJP are also presented. The superiority of the submonolayer diffusion equation over the conventional equation in the submonolayer film regime is demonstrated by comparing their theoretical diffusion coefficients with Waltman’s experimental data.

show abstract

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

Cited by 19 publications

References 14 publications

PFPE Lubricant Molecular Weight Effects on Slider-Disk Interactions

PFPE Lubricant Molecular Weight Effects on Slider-Disk Interactions

Thermal Behavior of Frictional Properties on Ultra-Thin Perfluoropolyether Lubricant Film

Disjoining Pressure Derived from the Lennard–Jones Potential, Diffusion Equation, and Diffusion Coefficient for Submonolayer Liquid Film

Contact Info

Product

Resources

About