Influences of Gases on the Tribological Properties of Pure Iron

2011 ◽  
Author(s):  
Kanao Fukuda ◽  
Joichi Sugimura
Keyword(s):  
Tribological Properties ◽  
Dry Friction ◽  
Pure Iron ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
The Other ◽  
Vacuum Vessel ◽  
Friction Coefficients ◽  
Wear Rates ◽  
Pin On Disk

In this study, trace oxygen and water as impurities in experimental gas environments were reduced to less than 10 ppb to eliminate their influences on the tribological properties. A pin-on-disk apparatus in an ultra-high vacuum vessel equipped with a gas filtering system enabled pure experimental gas environments. Dry friction tests clarified that the tribological properties of pure iron in ultra-high vacuum and argon were similar to each other. On the other hand, friction coefficients obtained in hydrogen and nitrogen were considerably lower than those obtained in ultra-high vacuum and argon. Specific wear rates of pin and disk were close to each other in ultra-high vacuum, argon and hydrogen while those took very different values in nitrogen. Hydrogen influenced the tribological properties of pure iron to some extent but the influences were not as much as that of nitrogen.

Carbon Nanotubes Improves the Tribological Properties of Ni60/Al2O3 Coatings

2013 ◽  
Vol 785-786 ◽  
pp. 864-871
Author(s):  
Shu Xiao ◽  
Xi Yun Cheng ◽  
De Gui Ma
Keyword(s):  
Carbon Nanotubes ◽  
Tribological Properties ◽  
Microstructural Characterization ◽  
Flame Spraying ◽  
Dual Roles ◽  
Wear Rates ◽  
Transmission Electron ◽  
Pin On Disk ◽  
Wear Tests ◽  
Original Coating

Carbon nanotubes (CNTs) was introduced into Ni60/Al2O3coating by flame spraying. The effect of adding CNTs on the tribological properties of the coating was studied by varying the CNTs content as 0.0, 1.5, 3.0 and 4.5 wt% in the Ni60/Al2O3powders. The microhardness tester was used to measure the microhardness of the coating. Wear tests were performed on a pin-on-disk tribometer, to evaluate the tribological properties of the Ni60/Al2O3/CNTs coatings. Microstructural characterization was performed using scanning and transmission electron microscopy. Ni60/Al2O3/CNTs coatings revealed a lower wear rate and friction coefficient compared with the original coating, and their wear rates and friction coefficients showed a decreasing trend with increasing mass fraction of CNTs within the range from 0 to 3.0 wt% due to the effects of the reinforcement and reduced friction of CNTs. The results showed that the CNTs played dual roles in improving the tribological performance of the coating, indirectly by influencing the microstructure and mechanical properties of the coating and directly by acting as a lubricating medium.

Influences of Trace Water in Hydrogen and Argon on the Tribological Properties of Pure Iron

2012 ◽  
Author(s):  
Kanao Fukuda ◽  
Masaaki Hashimoto ◽  
Joichi Sugimura
Keyword(s):  
Experimental Data ◽  
Tribological Properties ◽  
Pure Iron ◽  
Synergy Effect ◽  
Hydrogen Atoms ◽  
Wear Rates ◽  
Hydrogen Environment ◽  
Trace Water ◽  
Nascent Surface

Tribological properties of pure iron were studied in argon environments containing trace water which is controlled at the value between 1 and 10,000 ppb and virtually no oxygen. The experimental data were compared with those obtained in our previous study with the same conditions of experiment but in hydrogen. The influences of trace water were recognized in both gases and confirmed not peculiar to a hydrogen environment. The coefficients of friction and specific wear rates were different to some extent between argon and hydrogen environments. The differences were supposed to be attributed to the influences of hydrogen atoms which chemisorbed on pure iron atoms appeared on the nascent surface made by sliding. Whether hydrogen and water have synergy effect on influencing tribological properties was not clarified in this study.

scholarly journals Tribological Properties of Mo-Si-B Alloys Doped with La2O3 and Tested at 293–1173 K

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2011 ◽  
Author(s):  
Wenhu Li ◽  
Taotao Ai ◽  
Hongfeng Dong ◽  
Guojun Zhang
Keyword(s):  
High Temperature ◽  
Tribological Properties ◽  
Laser Scanning ◽  
Wear Behavior ◽  
Surface Oxidation ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Friction ◽  
Friction Coefficients ◽  
Wear Rates

According to the stoichiometric ratios of Mo-10Si-7B, Mo-12Si-8.5B, Mo-14Si-9.8B, and Mo-25Si-8.5B, some new Mo-Si-B alloys doped with 0.3 wt % lanthanum (III) oxide (La2O3) were prepared via liquid-liquid (L-L) doping, mechanical alloying (MA), and hot-pressing (HP) sintering technology. The phase-composition and microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The worn surfaces of the plate specimens were studied by confocal laser scanning microscopy (CLSM). Then, the tribological properties of Mo-Si-B alloy doped with sliding plate specimens of 0.3 wt % La2O3 were investigated against the Si3N4 ball specimens. The friction coefficients of Mo-Si-B alloys decreased and the wear rates of the alloys increased with test load. The high-temperature friction and wear behavior of Mo-Si-B alloy are related to the surface-oxidation and contact-deformation of the alloy at a high temperature. The low friction coefficients and the reduced wear rates are thought to be due to the formation of low friction MoO3 films. MoO3 changed the contact state of the friction pairs and behaved as lubricating films.

Solid lubrication with MoS2-Ti-C films for high-vacuum applications in a nuclear fusion experimental device

2018 ◽  
Vol 70 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Shanshuang Shi ◽  
Huapeng Wu ◽  
Yuntao Song ◽  
Heikki Handroos
Keyword(s):  
High Vacuum ◽  
Ultra High Vacuum ◽  
Experimental Device ◽  
Solid Lubrication ◽  
Hybrid Coatings ◽  
Vacuum Vessel ◽  
Coating Films ◽  
Content Type ◽  
Sputtering Deposition ◽  
Inner Vessel

Purpose This paper aims to present a study on composite coating films for solid lubrication applied on the surface of bearings and gears, which are exposed to the vacuum vessel of a tokamak fusion experimental device running under ultra-high vacuum conditions. Experimental advanced superconducting tokamak is a tokamak fusion experimental device running under ultra-high vacuum conditions. To avoid polluting the inner vessel environment, solid lubrication has been applied on the surface of bearings and gears, which are exposed to the vacuum. Design/methodology/approach Anti-friction MoS2 coatings integrated with Titanium and Carbon have been developed using the multi-target magnetron sputtering deposition technique. This paper presents the comparative testing of tribological properties for three kinds of MoS2-based coating layers. Findings Based on the test results, MoS2-Ti-C coating films are supposed to be the final selection because of the better performance of friction coefficient and lubrication longevity. Originality/value Finally, the detailed information has been characterized for the hybrid coatings, which can provide some references for applications of solid lubrications under similar conditions of high vacuum and temperature.

scholarly journals Tribological behaviors of Gra./Cu and CNTs/Cu composites with and without electric current

2018 ◽  
Vol 175 ◽  
pp. 01031
Author(s):  
Wei Xu ◽  
Binghong Li
Keyword(s):  
Powder Metallurgy ◽  
Electric Current ◽  
Tribological Properties ◽  
High Speed ◽  
Friction Coefficients ◽  
Wear Rates ◽  
Tribological Behaviors ◽  
Testing Condition ◽  
Worn Surfaces

Gra./Cu composites and CNTs/Cu composites were respectively fabricated by powder metallurgy techniques. The experiments of high speed sliding with and without electric current were carried out to investigate their tribological behaviors. The results show that the friction coefficients and wear rates with electric current are higher than without electric current; under the same testing condition the friction coefficients and wear rates of CNTs/Cu are lower and the worn surfaces are more planar than Gra./Cu. CNTs can debase the effect of heat generating during sliding process on the composites. The tribological properties of CNTs/Cu composites are more excellent than Gra./Cu composites.

scholarly journals Microstructure and Tribological Performance of Mesocarbon Microbead–Silicon Carbide Composites

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3127 ◽  
Author(s):  
Xiaojie Wang ◽  
Xiumin Yao ◽  
Hui Zhang ◽  
Xuejian Liu ◽  
Zhengren Huang
Keyword(s):  
Silicon Carbide ◽  
Tribological Properties ◽  
Dry Friction ◽  
Tribological Performance ◽  
Wear Process ◽  
Lubricating Film ◽  
Sic Composites ◽  
Pin On Disk ◽  
Disk Method ◽  
Pls Method

Mesocarbon microbead–silicon carbide (MCMB–SiC) composites with 0–30 wt % MCMBs were prepared by pressureless sintering (PLS) method at 2200 °C in Ar. The microstructure and tribological properties of the prepared composites were investigated. The results show that there was a finer grain size of SiC with the increase in MCMB content because MCMBs hinder the growth of SiC grains. The hardness of the composites decreased with increasing MCMB content, whereas the fracture toughness fluctuated showing a complex trend. The tribological properties of the composites under dry friction conditions were evaluated using the pin-on-disk method against a SiC counterpart. We found that the tribological properties of the samples were influenced by the oxide film or lubricating film that formed during the wear process on wear surfaces. Different wear mechanisms were found to be associated with differing MCMB contents.

scholarly journals Microstructure and Tribological Properties of Fe-Based Laser Cladding Layer on Nodular Cast Iron for Surface Remanufacturing

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 974
Author(s):  
Dongya Zhang ◽  
Zhongwei Li ◽  
Hongwei Fan ◽  
Hongbin Rui ◽  
Feng Gao
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Tribological Properties ◽  
Dry Friction ◽  
Equivalent Stress ◽  
Nodular Cast Iron ◽  
Friction Coefficients ◽  
Cladding Layer ◽  
Starved Lubrication ◽  
Lubrication Conditions

In this study, a cladding layer and nitriding layer were prepared on nodular cast iron, to provide guidance for remanufacturing of nodular cast iron. Their microstructure and composition and the tribological properties under dry and starved lubrication conditions were studied. Meanwhile, the contact stresses at different friction stages were simulated through the finite element method. The micro-hardness of the cladding layer and nitriding layer were 694 HV0.5 and 724.5 HV0.5, which were 4 times and 4.2 times higher than that of the substrate. For dry friction conditions, the wear resistance of the cladding layer and nitriding layer were 113.2 times and 65.5 times that of the substrate. For starved lubrication conditions, the friction coefficients of the cladding layer and nitriding layer were lower than that of the substrate. In addition, their average friction coefficients and wear resistance were gradually reduced with the increase in load. Contact simulation showed that the maximum equivalent stress gradually increased with the friction coefficient during the dry friction, and the peak value of von Mises stress on the nitriding layer was larger than that of the cladding layer, and the nitriding layer was more likely to yield and peel off.

Improvement of Tribological Properties of Mosa Films by Forming Interlayers and/ or Bombarding with Ions

1991 ◽  
Vol 239 ◽  
Author(s):  
Akihiko Matsui ◽  
Yoshimi Kagimoto
Keyword(s):  
Tribological Properties ◽  
High Speed ◽  
High Vacuum ◽  
Surface Hardness ◽  
Ultra High Vacuum ◽  
High Vacuum Condition ◽  
Wear Life ◽  
Sputter Deposited ◽  
Film Substrate ◽  
Ultra High Vacuum Condition

ABSTRACTThe effects of forming interlayers and/or bombarding with ions on the tribological properties of the sputter-deposited MoS2 films were investigated. The MoS2 films on substrates of Ti-alloy, martensitic stainless steel and high speed tool steel with TIN interlayers were evaluated by ball/disk sliding tests under ultra-high vacuum condition. Furthermore, nitrogen- or sulfer-ion-bombarded MoS2 films tested too. The test results showed correlation between the surface hardness of substrates and the wear life of MoS2 films. The wear life of the ion-bombarded MoS2 films was improved by mixing film/substrate interface.

scholarly journals Experimental Studies of Lubricant Flow and Friction in Partially Filled Gaps

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 110 ◽  
Author(s):  
Michael Müller ◽  
Lukas Stahl ◽  
Georg-Peter Ostermeyer
Keyword(s):  
Dry Friction ◽  
Hydrodynamic Lubrication ◽  
Experimental Studies ◽  
Friction Coefficients ◽  
Lubricated Contacts ◽  
Lubricant Flow ◽  
Wide Range ◽  
Friction Parameters ◽  
Pin On Disk ◽  
Fail Safe

Starved lubrication is an important strategy for minimizing the amount of lubricant needed, and also inevitably occurs during idling and fail-safe lubrication. In this regime, however, the flow of the lubricant and the related friction coefficients are yet to be fully understood. This research aims to make fundamental contributions to the understanding of contact mechanics of partially lubricated contacts. Recent experiments with a pin-on-disk tribometer examined the microscopic behavior of partially filled gaps. Using a new experimental setup on a macroscale, new insights into partially filled gaps with rough surfaces were gained. This work presents the systematic analyses of the lubricant flow, friction coefficients, and other variables over a wide range of friction parameters. Distinct friction behaviors were observed, and similar effects occur on both the micro and macroscale. The experimental results show that a typical Stribeck characteristic is visible regarding not only the relative velocity, but also regarding the lubricant filling level in the gap. The fluid exhibits a variety of flow patterns for various velocities and viscosities. The patterns relate to different friction regimes, such as dry friction and mixed lubrication. It is concluded that the filling level is a valid parameter for regulating the transition from dry friction to hydrodynamic lubrication. These findings are quantified regarding the filling level and it is shown that for the identification of the friction regimes the filling level is an independent parameter in addition to the established parameters like speed, viscosity and pressure.

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