The effect of transfer layers on the surface contact and wear of carbon-graphite materials

Williams, John A.; Morris, James Harry; Ball, Andrew

doi:10.1016/s0301-679x(97)00034-0

Cited by 42 publications

(21 citation statements)

References 14 publications

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“…So that for conditions in which the graphite can easily lubricate the sliding surfaces a significant decrease, by several orders of magnitude, was observed both in coefficient of friction and wear rate. The good tribological properties of graphite is basically associated with its anisotropic structure and its weak interlayer van der Waals forces [10], as well as the fact that it provides a large lubricating surface area in the lubricant mixture during sliding. The interactions between these weak interlayers cause smearing processes and the formation of a very thin lubricating film between the sliding surfaces [10].…”

mentioning

confidence: 99%

A study on graphite extrusion phenomenon under the sliding wear response of cast iron using microindentation and microscratch techniques

Ghasemi

Elmquist

2014

Wear

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A study on graphite extrusion phenomenon under the sliding wear response of cast iron using microindentation and microscratch techniques. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThis study focuses on the graphite flakes extrusion mechanism during microindenting and microscratching of cast iron. Observations on the graphite response under abrasive conditions revealed that the matrix deformation which is occurred during a sliding wear condition could have a significant influence on its lubricating performance. Simple microindentation and microscratch tests were conducted to explore the lamellar graphite contribution to tribofilm formation under abrasive wear conditions. The results obtained showed that induced plastic deformation which developed adjacent to the graphite compressed the lamellas and in turn resulting in extrusion of the graphite from its natural position. Further investigations on both indentation and scratch tests indicated that, surprisingly, the graphite began to be fractured and extruded from the centre of graphite lamellas, irrespective of the lamella size. Additionally, a mechanism was proposed to explain the selflubricating and the extrusion behaviour of the lamellar graphite as a result of indentation.

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confidence: 99%

A study on graphite extrusion phenomenon under the sliding wear response of cast iron using microindentation and microscratch techniques

Ghasemi

Elmquist

2014

Wear

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“…Removal of water from friction lining containing graphitic carbon may lead to an increase in friction [13], and exposure of the braking interface to water may lead to reduced friction by causing metallurgical changes in the iron components of a brake system: hydrogen from water (or from the friction material) may diffuse into the adjacent iron and chemically change iron carbide particles, leading to the formation of metal foils that degrade brake performance [14]. Oxidation of exposed metal surfaces (or conversely, the lack of oxide layers) is known to have significant effect on the friction between metals [15] and the accumulation of a stable transfer layer of wear debris has great effect on both the level of friction and the rate of wear [ 16,17].…”

Section: Centrifugal Friction Brake Designmentioning

confidence: 99%

“…For a first-order speed dependent brake such as an electric generator brake, drag-torque = c brake*omega ideal_lowering_speed= load*radiusA2/c brake (14) (15) For a second-order brake such as a centrifugal friction brake, drag-torque = c brake*omegaA2 (16) ideal_lowering_speed= (load*radius'3/c brake) 0.5 (17) Figure 10 shows idealized and actual deployment profiles for a particular cone-shaped spool with two types of brake sized for lowering a payload in the same amount of time. The actual speed (here, the result of a more complete mechanism simulation) seeks the ideal speed as masses are accelerated.…”

Section: Descent Mechanisms and Speed Controlmentioning

confidence: 99%

Mechanisms for Lowering Tethered Payloads: Lessons Learned from the Mars Exploration Program

Gradziel

Holgerson

2008

2008 IEEE Aerospace Conference

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“…That pattern of friction behavior, i.e., a quick rise in friction in the early part of sliding and then a decrease to a steady value, is usually regarded as being caused by the running-in effect, which is associated with changes in surface roughness and generation and distribution of wear debris. [32][33][34] Figure 12 shows the cross-sectional surface profiles of the wear tracks on the three disk specimens. The worn surfaces were all rough, and the width of the wear tracks increased with increasing graphite addition.…”

Section: June 2003mentioning

confidence: 99%

Tribological Properties of Silicon Carbide and Silicon Carbide–Graphite Composite Ceramics in Sliding Contact

Zhou

Yamauchi

Kanzaki

2003

Journal of the American Ceramic Society

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A monolithic SiC ceramic and two SiC–C composite ceramics containing 10 and 20 vol% graphite were fully densified with Al4C3 and B4C as additives. The tribological properties of these materials were evaluated by sliding against sintered silicon carbide under dry conditions using two tribometers, block‐on‐ring and pin‐on‐disk, where wear occurred under low and high contact stresses, respectively. For all three materials, under low stress, worn surfaces were smooth and wear processes were dominated by tribochemical reaction; under high stress, worn surfaces were rough and wear processes were dominated by fracture and three‐body abrasion. A lubricating effect of the graphite particles in the SiC–C composites was observed in all sliding tests. However, while the addition of graphite could concurrently result in a reduction in friction and an increase in wear resistance in the block‐on‐ring tests, the addition of graphite led to sharply enhanced wear rates despite the lowered coefficients of friction in the pin‐on‐disk tests. The cause for that difference was attributed to the effect of both the hardness of the materials and the contact stresses.

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The effect of transfer layers on the surface contact and wear of carbon-graphite materials

Cited by 42 publications

References 14 publications

A study on graphite extrusion phenomenon under the sliding wear response of cast iron using microindentation and microscratch techniques

A study on graphite extrusion phenomenon under the sliding wear response of cast iron using microindentation and microscratch techniques

Mechanisms for Lowering Tethered Payloads: Lessons Learned from the Mars Exploration Program

Tribological Properties of Silicon Carbide and Silicon Carbide–Graphite Composite Ceramics in Sliding Contact

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