The Tribological Performance of Metal-/Resin-Impregnated Graphite under Harsh Condition

Graphite-based composites are well recognized as ideal functional materials in mechanical seals, bearings of canned pumps, and electrical contact systems because of their outstanding self-lubricating ability, thermostability, and chemical stability. Working in harsh conditions is a huge challenge for the graphite materials, and their tribological properties and wear mechanisms are not well studied. In this study, the tribological performance of metal-impregnated graphite, resin-impregnated graphite, and non-metal-impregnated graphite under high temperature and high load are studied using a ball-on-disc tribometer. The results show that the metal-impregnated graphite (Metal-IG) has a stable friction regime and exhibits better anti-friction and anti-wear properties than that of resin-impregnated graphite (Resin-IG) and non-impregnated graphite (Non-IG) under extreme pressure (200~350 MPa) and high temperature (100–350 °C). The Metal-IG and Resin-IG can reduce the wear depth by 60% and 80%, respectively, when compared with Non-IG substrate. The impregnated materials (metal or resin) can enhance the strength of the graphite matrix and improve the formation of graphite tribofilm on the counterpart surfaces. Friction-induced structural ordering of graphite and slight oxidation of metal in the formed mechanically mixed layer is also beneficial for friction and wear reduction. This study demonstrates the tribological characteristics of impregnated graphite under harsh conditions and provides the experimental basis for the advanced usage of high-reliability and self-lubrication graphite composites.

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Tribological performance of three surface-modified piston rings matched with chromium-plated cylinder liner

Industrial Lubrication and Tribology ◽

10.1108/ilt-11-2015-0164 ◽

2017 ◽

Vol 69 (2) ◽

pp. 276-281 ◽

Cited By ~ 3

Author(s):

Feng Zhu ◽

Jiujun Xu ◽

Xiaoguang Han ◽

Yan Shen ◽

Mei Jin

Keyword(s):

Piston Ring ◽

Cylinder Liner ◽

Tribological Performance ◽

Wear Depth ◽

Wear Properties ◽

Piston Rings ◽

Ic Engine ◽

Content Type ◽

Friction And Wear Properties ◽

Surface Modified

Purpose The paper aims to investigate the friction and wear properties of three surface-modified piston rings matched with a chromium-plated cylinder liner. Design/methodology/approach Samples were taken from the chromium-plated cylinder liner, Cr-Al2O3 ring, CrN ring and Mo ring. Tribo-tests were conducted on a reciprocating sliding tribometer under fully formulated engine oils. Friction coefficients and wear depths of three friction pairs were tested. Surface morphologies of cylinder liners and piston rings before and after test were analyzed. Findings Experimental results show that in the Cr-Al2O3 piston ring, scuffing occurred easily when matched with the chromium-plated cylinder liner; compared with the Mo ring, the CrN ring could decrease the wear depth of the piston ring from 2.7 to 0.2 μm, and the wear depth of cylinder liner remained; however, the friction coefficient increased from 0.113 to 0.123. The tribological performances of three surface-modified piston rings were significantly different when they matched with chromium-plated cylinder liner. Originality/value Chromium-plated cylinder liner and the three kinds of surface-modified piston rings have excellent friction and wear properties, respectively. However, according to the systematic characteristics of internal combustion (IC) engine tribology, only the appropriate cylinder liner–piston ring can improve the tribological performance of the IC engine. This paper reports the tribological performance of three surface-modified piston rings matched with a chromium-plated cylinder liner. The results can be used as reference for the design of high-power-density diesel engine.

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Effect of High Temperature on Wear Behavior of Stir Cast Aluminium/Boron Carbide Composites

Mechanics and Mechanical Engineering ◽

10.2478/mme-2018-0082 ◽

2020 ◽

Vol 22 (4) ◽

pp. 1031-1046

Author(s):

X. Canute ◽

M. C. Majumder

Keyword(s):

High Temperature ◽

Wear Rate ◽

Boron Carbide ◽

Wear Behavior ◽

Base Alloy ◽

Weight Fraction ◽

Sliding Velocity ◽

Wear Properties ◽

High Temperature Wear ◽

The Matrix

AbstractThe need for development of high temperature wear resistant composite materials with superior mechanical properties and tribological properties is increasing significantly. The high temperature wear properties of aluminium boron carbide composites was evaluated in this investigation. The effect of load, sliding velocity, temperature and reinforcement percentage on wear rate was determined by the pin heating method using pin heating arrangement. The size and structure of base alloy particles change considerably with an increase of boron carbide particles. The wettability and interface bonding between the matrix and reinforcement enhanced by the addition of potassium flurotitanate. ANOVA technique was used to study the effect of input parameters on wear rate. The investigation reveals that the load had higher significance than sliding velocity, temperature and weight fraction. The pin surface was studied with a high-resolution scanning electron microscope. Regression analysis revealed an extensive association between control parameters and response. The developed composites can be used in the production of automobile parts requiring high wear, frictional and thermal resistance.

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Low-Temperature Post-Oxidation Annealing Using Atomic Hydrogen Radicals Generated by High-Temperature Catalyzer for Improvement in Reliability of Thermal Oxides on 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.527-529.999 ◽

2006 ◽

Vol 527-529 ◽

pp. 999-1002

Author(s):

Junji Senzaki ◽

Atsushi Shimozato ◽

Kenji Fukuda

Keyword(s):

High Temperature ◽

Low Temperature ◽

Atomic Hydrogen ◽

High Reliability ◽

Hydrogen Atmosphere ◽

Exposed Sample ◽

New Apparatus ◽

Hydrogen Radical ◽

Hydrogen Radicals ◽

Sic Wafer

Low-temperature post-oxidation annealing (POA) process of high-reliability thermal oxides grown on 4H-SiC using new apparatus that generates atomic hydrogen radicals by high-temperature catalyzer has been investigated. Atomic hydrogen radicals were generated by thermal decomposition of H2 gas at the catalyzer surface heated at high temperature of 1800°C, and then exposed to the sample at 500°C in reactor pressure of 20 Pa. The mode and maximum values of field-to-breakdown are 11.0 and 11.2 MV/cm, respectively, for the atomic hydrogen radical exposed sample. In addition, the charge-to-breakdown at 63% cumulative failure of the thermal oxides for atomic hydrogen radical exposed sample was 0.51 C/cm2, which was higher than that annealed at 800°C in hydrogen atmosphere (0.39 C/cm2). Consequently, the atomic hydrogen radical exposure at 500°C has remarkably improved the reliability of thermal oxides on 4H-SiC wafer, and is the same effect with high-temperature hydrogen POA at 800°C.

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Evolution of Microstructure and High-Temperature Tribological Performance of Self-Lubricating Nickel-Based Composite Tungsten Inert Gas Coatings

Journal of Materials Engineering and Performance ◽

10.1007/s11665-021-06008-4 ◽

2021 ◽

Author(s):

Suresh Gudala ◽

M. R. Ramesh ◽

Siva Shanmugam Nallathambi

Keyword(s):

High Temperature ◽

Tribological Performance ◽

Inert Gas ◽

Evolution Of Microstructure

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Effect of Boron Carbide Addition on Wear Resistance of Aluminum Matrix Composites Fabricated by Stir Casting and Hot Rolling Processes

Metals ◽

10.3390/met11060989 ◽

2021 ◽

Vol 11 (6) ◽

pp. 989

Author(s):

Donghyun Lee ◽

Junghwan Kim ◽

Sang-Kwan Lee ◽

Yangdo Kim ◽

Sang-Bok Lee ◽

...

Keyword(s):

Wear Resistance ◽

Boron Carbide ◽

Hot Rolling ◽

Rolling Direction ◽

Aluminum Matrix ◽

Stir Casting ◽

Aluminum Matrix Composites ◽

Wear Depth ◽

Wear Properties ◽

B4c Particles

In this study, to evaluate the effect of boron carbide (B4C) addition on the wear performance of aluminum (Al), Al6061 and 5, 10, and 20 vol.% B4C/Al6061 composites were manufactured using the stir casting and hot rolling processes. B4C particles were randomly dispersed during the stir casting process; then, B4C particles were arranged in the rolling direction using a hot rolling process to further improve the B4C dispersion and wear resistance of the composites. Furthermore, a continuous interfacial layer between B4C and the Al6061 matrix was generated by diffusion of titanium (Ti) and chromium (Cr) atoms contained in the Al6061 alloy. Wear depth and width of the composites decreased with increasing B4C content. Furthermore, with B4C addition, coefficient of friction (COF) improved as compared with that of Al6061. The results indicate that interface-controlled, well-aligned B4C particles in the friction direction can effectively increase the wear properties of Al alloys and improve their hardness.

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Oil-soluble ionic liquid to lubricate silicon

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650120984880 ◽

2021 ◽

pp. 135065012098488

Author(s):

Waleed Al-Sallami ◽

Pourya Parsaeian ◽

Abdel Dorgham ◽

Anne Neville

Keyword(s):

Ionic Liquid ◽

High Temperature ◽

Friction And Wear ◽

Tribological Performance ◽

Considerable Reduction ◽

Zinc Dialkyldithiophosphate ◽

Lubrication Mechanism ◽

Wear Coefficient ◽

Wear Performance ◽

Micro Scale

Trihexyltetradecylphosphonium bis(2-ethylhexyl)phosphate (phosphonium phosphate) ionic liquid is soluble in non-polar lubricants. It has been proposed as an effective anti-wear additive comparable to zinc dialkyldithiophosphate. Previously, phosphonium phosphate has shown a better anti-wear performance under some conditions such as high temperature. In this work, the tribological performance and the lubrication mechanism of phosphonium phosphate are compared with that of zinc dialkyldithiophosphate when lubricating silicon under various tribological conditions. This can lead to an understanding of the reasons behind the superior anti-wear performance of phosphonium phosphate under some conditions. A micro-scale study is conducted using a nanotribometer. The results show that both additives lead to a considerable reduction in both friction and wear coefficients. The reduction in the wear coefficient is mainly controlled by the formation of the tribofilm on the rubbing surfaces. Zinc dialkyldithiophosphate can create a thicker tribofilm, which results in a better anti-wear performance. However, the formation of a thicker film will lead to a faster depletion and thus phosphonium phosphate can provide better anti-wear performance when the depletion of zinc dialkyldithiophosphate starts.

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