Humidity Effects on Friction and Wear Between Dissimilar Metals

Barthel, Anthony J.; Gregory, Matthew D.; Kim, Seong H.

doi:10.1007/s11249-012-0026-5

Cited by 26 publications

(61 citation statements)

References 42 publications

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“…For example, adsorbed water vapor at high relative humidity results in electrochemical reactions between dissimilar metals such as AISI 440C stainless steel and copper. Figure 2 shows the change in the wear pattern of a copper substrate when sliding using 440C stainless steel ball occurs at increasing humidity [16]. While dry sliding resulted in a plastic deformation in copper along with mild abrasive wear ( Fig.…”

Section: Environmental Effect On Friction and Wear Of Metalsmentioning

confidence: 99%

“…On the other hand, friction tests at high RH (>80%) produced ironcontaining wear debris on the copper surface ( Fig. 2(c)) indicating that the hard stainless steel was worn and the soft copper was intact [16]. This is because, after the corrosion-resistant chromium oxide layer on stainless steel was damaged during sliding, the thick layer of adsorbed water acted as an electrolyte solution allowing the steel alloy to undergo galvanic corrosion.…”

Section: Environmental Effect On Friction and Wear Of Metalsmentioning

confidence: 99%

“…Adsorbed vapors can be essential for super-lubricious behavior [13] or they can deteriorate lubricity [14]. They can prevent wear [15] or result in catastrophic adhesive wear and tribochemical reactions [16]. Adsorbed vapors also play a crucial role in nano-scale contact by controlling adhesion and interfacial shear [17,18].…”

Section: Introductionmentioning

confidence: 99%

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Vapors in the ambient—A complication in tribological studies or an engineering solution of tribological problems?

et al. 2015

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Tribology involves not only two-body contacts of two solid materials-a substrate and a counter-surface; it often involves three-body contacts whether the third body is intentionally introduced or inevitably added during the sliding or rubbing. The intentionally added third body could be lubricant oil or engineered nanomaterial used to mitigate the friction and wear of the sliding contact. The inevitably added third body could be wear debris created from the substrate or the counter surface during sliding. Even in the absence of any solid third-body between the sliding surfaces, molecular adsorption of water or organic vapors from the surrounding environment can dramatically alter the friction and wear behavior of solid surfaces tested in the absence of lubricant oils. This review article covers the last case: the effects of molecular adsorption on sliding solid surfaces both inevitably occurring due to the ambient test and intentionally introduced as a solution for engineering problems. We will review how adsorbed molecules can change the course of wear and friction, as well as the mechanical and chemical behavior, of a wide range of materials under sliding conditions.

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Section: Environmental Effect On Friction and Wear Of Metalsmentioning

confidence: 99%

Section: Environmental Effect On Friction and Wear Of Metalsmentioning

confidence: 99%

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Vapors in the ambient—A complication in tribological studies or an engineering solution of tribological problems?

et al. 2015

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“…This value is considerably higher than the lubricating examples of boric acid reported elsewhere [5]. Friction coefficient spikes above 1.0 are due to wear of the copper substrate and have been observed for unlubricated copper samples [29]. The period of friction near 0.3 suggests that the boric acid coating lubricates by a phenomenon other than due to its lamellar structure, possibly third body lubrication.…”

Section: Effects Of Vapor Adsorption On Friction and Wear Of Boric Acmentioning

confidence: 67%

“…A detailed description of this system is available elsewhere [29]. AES analysis was conducted with a PHI 670 field emission spectrometer using a beam voltage of 10 keV and current of 10 nA, and system pressure was in the 10 -9 torr range.…”

Section: Methodsmentioning

confidence: 99%

Origin of Ultra-Low Friction of Boric Acid: Role of Vapor Adsorption

2015

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Boric acid is a lamellar solid lubricant that can give an ultra-low friction coefficient. The origin of this ultra-low friction of boric acid was investigated using tribology and spectroscopy techniques in inert, humid, and organic vapor conditions. It was found that boric acid itself experiences high friction and catastrophic surface wear when rubbed with a stainless steel ball in dry nitrogen or oxygen environments, but it gives very low friction (l = 0.06) in humid and acetone vapor environments. Short-chain alcohol vapors (ethanol and n-pentanol) did not show these ultra-low friction values. Vibrational spectroscopy indicates that the lubricating vapors do not adsorb on the basal plane of the boric acid crystal but likely adsorb onto the edge sites of the lamella. The alcohol molecules impinging from the gas phase readily react with the boric acid to form a high vapor pressure molecule that desorbs from the surface. The ''unlocking'' of the highenergy edge sites by adsorbed acetone and water vapor appears to be needed for the lamella to shear along the basal plane direction.

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