Bonding of Hard Disk Lubricants with OH-Bearing End Groups

Kasai, Paul H.; Shimizu, Tsuyoshi

doi:10.1007/s11249-012-9916-9

Cited by 9 publications

(2 citation statements)

References 3 publications

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“…Since the physical bonding is relatively weak (~ 20 kJ/mol) it be can easily disrupted by the ambient thermal energy or removed by solvent rinsing [35]. As proposed by Kasai [35] and [37], alcohol molecules can also chemisorb to the carbon surface, where chemical bonding occurs when the hydrogen atom from the hydroxyl endgroup migrates to the dangling bond inside the amorphous carbon structure, while the remaining alkoxy group interacts with the unsaturated system at the surface, Figs 7c. We assume that the fatty acids can chemisorb in a similar way, Fig 7d. According to Kasai [35] and [37], such an adsorption process is slow at room temperature, but it can be accelerated by elevating the temperature.…”

Section: Tentative Adsorption Mechanisms For Alcohol and Fatty Acidmentioning

confidence: 97%

“…Similar to steel, amorphous carbon coatings that are exposed to ambient air and moisture also possess a certain amount of oxides and hydroxides on the surface, see [34] and [35]. The amorphous structure and oxidation cause these surfaces to be heterogeneous in the sense that they contain exposed adsorption sites with a range of affinities for interactions with polar end-groups [36].…”

Section: Static Conditionsmentioning

confidence: 99%

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Comparison of Alcohol and Fatty Acid Adsorption on Hydrogenated DLC Coatings Studied by AFM and Tribological Tests

Simič¹,

Kalin²

2013

SV-JME

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Adsorption on hydrogenated diamond-like carbon (DLC) coatings with respect to boundary lubrication has been studied only very rarely, even though such adsorption has proved to be one of the main boundary-lubricating mechanisms for metal contacts. For this reason, we used atomic force microscopy (AFM) and tribotests to study the ability of hexadecanol and hexadecanoic acid to adsorb onto DLC and affect the tribological properties of DLC coatings, where steel was used as a reference. We have shown that alcohols and fatty acids can adsorb onto the DLC under static conditions. However, under dynamic tribocontact conditions, although alcohol and fatty acid molecules help to decrease the wear of the coatings, they are inefficient in reducing the friction. In all the experiments the fatty acid proved to have superior adsorption abilities compared to the corresponding alcohol. Based on our results and the existing literature, tentative adsorption mechanisms that include an environmental species effect, a temperature effect and a tribochemical effect are discussed for DLC surfaces.

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