Effect of Head–Disk Interface Biasing and Relative Humidity on Wear of Thermal Flying Height Control Sliders

Matthes, Liane; Spada, F. E.; Ovcharenko, Andrey; Knigge, Bernhard; Talke, Frank E.

doi:10.1007/s11249-017-0828-6

Cited by 6 publications

(4 citation statements)

References 21 publications

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“…It should be noted that the degradation of the lubricant strand in the main chain (leading to the production of C 27 H 9 O 11 F 46 and C 15 H 9 O 6 F 22 ) occurs through the C–O bond cleavage, which is similar to the Kasai mechanism . If we compare the different bonds of PFPE lubricants, we observe that the C–O bond is the weakest bond (with a dissociation energy of 360 kJ/mol) in comparison to the C–F, O–H, and C–H bonds (with dissociation energies of 473, 464, and 414 kJ/mol respectively) . In addition, the C–O bond is a polar bond in which the carbon atom is partially positively charged and the oxygen atom is partially negatively charged.…”

Section: Resultsmentioning

confidence: 79%

“…This effect is consistent with previous experimental results. 31 The 22 In addition, the C−O bond is a polar bond in which the carbon atom is partially positively charged and the oxygen atom is partially negatively charged. As a result, the C−O bond can be broken easily and is subject to cleavage during lubricant degradation.…”

Section: Degradation Of Lubricant With Water and Oxygenmentioning

confidence: 99%

“…This is especially important for HAMR systems because of their higher temperatures . In general, the main causes of lubricant degradation can be categorized as thermal decomposition, catalytic decomposition, mechanical degradation by a shearing process, and electron-mediated degradation. − Experimental studies on the degradation of PFPE lubricants in the presence of different components have been described in several papers. For instance, the degradation and tribological properties of PFPE lubricants in the presence of diamond-like carbon (DLC) structures have been studied experimentally. − Zhao and Bhushan , used a mass spectrometer to investigate the degradation of PFPE lubricants on the magnetic media.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Dynamics Simulations of Perfluoropolyether Lubricant Degradation in the Presence of Oxygen, Water, and Oxide Nanoparticles using a ReaxFF Reactive Force Field

2018

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The degradation of a perfluoropolyether lubricant, i.e., D4OH, was studied in the presence of a number of different components in a computer hard disk drive using ReaxFF reactive force field-based molecular dynamics simulations. The chemical reaction between nine D4OH strands with oxygen, water, oxide nanoparticles including SiO 2 , goethite (FeO(OH)), and Fe 2 O 3 was simulated by using reactive molecular dynamics simulation at T = 1500 K. All oxide nanoparticles were used in three different configurations:(1) untreated − cut from the crystalline structure without further treatment; (2) pretreated with dry air; and (3) pretreated with wet air to simulate a realistic environment. It was observed that water molecules strongly affect the degradation rate of the D4OH lubricant while oxygen molecules do not play a significant role. Moreover, the results indicated that the presence of these nanoparticles in any form accelerates the lubricant degradation. Untreated silica and Goethite nanoparticles have stronger effects on the degradation rates of lubricant strands in comparison to dry-air-treated and wet-airtreated nanoparticles, while in the case of Fe 2 O 3 nanoparticles wet-air-treated nanoparticles have the strongest effect on the degradation rates of lubricant strands.

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Section: Resultsmentioning

confidence: 79%

Section: Degradation Of Lubricant With Water and Oxygenmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular Dynamics Simulations of Perfluoropolyether Lubricant Degradation in the Presence of Oxygen, Water, and Oxide Nanoparticles using a ReaxFF Reactive Force Field

2018

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“…Ma et al [13] theoretically studied the influence of the adsorbed water film on the heat transfer in a slider bearing, highlighting an increase of the heat transfer coefficient. Matthes et al [14,15] experimentally investigated the influence of relative humidity on the touch-down power of an aerodynamic slider bearing. They reported a reduction of touch-down energy loss with increasing humidity ratios.…”

Section: Nature Of the Issuementioning

confidence: 99%

Effects of humid air on aerodynamic journal bearings

Guenat

Schiffmann

2018

Tribology International

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The development of aerodynamic bearings applications where ambient conditions cannot be controlled (e.g., for automotive fuel cell compressor) raises the question of the effects of condensation in the humid air on performance. A modified Reynolds equation is obtained in relation to humid air thermodynamic equations, accounting for the variation of compressibility and viscosity in the gas mixture. The load capacity and stability of plain and herringbone-grooved journal bearings is computed on a wide range of operating and ambient conditions. In general, performance metrics show an independence on humid-air effects at moderated temperature, although the stability of the grooved journal bearing exhibits strong variations in particular conditions. In consequence, a safety margin of 25% is suggested for the critical mass.

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Effect of laser heating on nanoscale wear of DLC thin films in an air environment

et al. 2018

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Effect of Head–Disk Interface Biasing and Relative Humidity on Wear of Thermal Flying Height Control Sliders

Cited by 6 publications

References 21 publications

Molecular Dynamics Simulations of Perfluoropolyether Lubricant Degradation in the Presence of Oxygen, Water, and Oxide Nanoparticles using a ReaxFF Reactive Force Field

Molecular Dynamics Simulations of Perfluoropolyether Lubricant Degradation in the Presence of Oxygen, Water, and Oxide Nanoparticles using a ReaxFF Reactive Force Field

Effects of humid air on aerodynamic journal bearings

Effect of laser heating on nanoscale wear of DLC thin films in an air environment

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