Triboemission And Wear Of Hydrogenated Carbon Films

1995 ◽  
Vol 409 ◽  
Author(s):  
Keiji Nakayama
Keyword(s):  
Friction Coefficient ◽  
Electron Emission ◽  
Glass Substrate ◽  
Carbon Films ◽  
Lubricating Oil ◽  
Carbon Overcoat ◽  
Dry Air ◽  
Air Atmosphere ◽  
Frictional System ◽  
Frictional Surfaces

AbstractIt is suggested that perfluoropolyether lubricating oil coatings applied to the carbon overcoat film of magnetic recording layers become decomposed by electrons emitted from frictional surfaces. However, no work has at yet been reported as to triboemission of electrons from frictional carbon films.This paper describes the behavior of triboemission of electrons and the friction coefficient during wear of sputtered hydrogenated carbon films (with various hydrogen contents on the glass substrate). The triboemission of electrons, together with friction coeficient, was measured in a frictional system of Al2O3 sliding on carbon films in a reduced dry air atmosphere. The worn surfaces of the carbon films were then observed using both a SEM and an AFM. The results showed that intense triboemission of electrons were observed during wear of hydrogenated carbon films. The electron emission intensity and friction coefficient transit from low to high with hydrogen content in the film. These results are discussed including physical properties of the carbon films such as internal stress and surface wettability.

Tribo-Electromagnetic Phenomena of Hydrogenated Carbon Films—Tribo-Electrons, -Ions, -Photons, and -Charging

1997 ◽  
Vol 119 (4) ◽  
pp. 764-768 ◽  
Author(s):  
Keiji Nakayama ◽  
Benyebka Bou-Said ◽  
Hiroshi Ikeda
Keyword(s):  
Friction Coefficient ◽  
Hydrogen Content ◽  
Emission Intensity ◽  
Charged Particles ◽  
Ambient Air ◽  
Carbon Films ◽  
Frictional Contacts ◽  
Plasma State ◽  
Frictional System ◽  
Positively Charged

Triboemission of negatively charged particles and positively charged particles, tribo-charging and friction coefficient were measured simultaneously using a frictional system with diamond sliding on hydrogenated carbon films in ambient air. The hydrogen content of the carbon films varied from 0 to 43 at. percent. All the carbon films tested emitted both negatively and positively charged particles during sliding. For films with hydrogen content of from 0 to 15 at. percent, neither tribo-charging nor tribo-photons were observed; beyond 15 at. percent hydrogen content, tribo-charging and tribo-photons were observed. With increasing hydrogen content, the emission intensity of the negatively and positively charged particles, photons and tribo-charging increased. It is concluded that a micro-plasma state is formed at the frictional contacts of diamonds sliding on hydrogenated carbon films.

Benzylamine Tartrate as an Organic Glass Substrate for Carbon Films by Evaporation

1970 ◽  
Vol 28 ◽  
pp. 484-485
Author(s):  
A. C. Faberge
Keyword(s):  
Vapor Pressure ◽  
Viscous Liquid ◽  
Glass Substrate ◽  
Room Temperature ◽  
Carbon Film ◽  
Carbon Films ◽  
Organic Glass ◽  
Spectroscopic Examination ◽  
Polymeric Substrates

Benzylamine tartrate (m.p. 63°C) seems to be a better and more convenient substrate for making carbon films than any of those previously proposed. Using it in the manner described, it is easy consistently to make batches of specimen grids as open as 200 mesh with no broken squares, and without individual handling of the grids. Benzylamine tartrate (hereafter called B.T.) is a viscous liquid when molten, which sets to a glass. Unlike polymeric substrates it does not swell before dissolving; such swelling of the substrate seems to be a principal cause of breakage of carbon film. Mass spectroscopic examination indicates a vapor pressure less than 10−9 Torr at room temperature.

Effect of RF Negative Bias on the Structure and Performance of Diamond-Like Carbon Films in ECR Plasma

2013 ◽  
Vol 423-426 ◽  
pp. 756-761
Author(s):  
Li Jun Sang ◽  
Qiang Chen ◽  
Zhong Wei Liu ◽  
Zheng Duo Wang
Keyword(s):  
Friction Coefficient ◽  
Electron Cyclotron Resonance ◽  
Crystalline Silicon ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Negative Bias ◽  
Film Property ◽  
Ecr Plasma ◽  
Peak Intensity ◽  
Stretching Vibration

Diamond-like carbon films (DLC) were deposited on single crystalline silicon surface under different RF negative bias in microwave electron cyclotron resonance (ECR) plasma source. The chemical structure and morphology were characterized by Fourier transformation infrared spectroscopy (FTIR) and atomic force microscopy (AFM). The friction coefficient of films was measured to examine the film property later. The results show that the smooth and compact deposited films were typical hydrogenated diamond-like carbon with CHn stretching vibration in 2800-3000cm-1. It is noticed that with the increase of RF bias on the substrate the peak intensity for C-H stretching vibration in spectrum between 2800cm-1~3000cm-1 increased at the beginning and then decreased, which caused the friction coefficient of the film being smaller and then larger in reverse. In 50W RF biased power one can obtain the maximum-CHn peak intensity and the minimum friction coefficient.

scholarly journals Robust low friction performance of graphene sheets embedded carbon films coated orthodontic stainless steel archwires

Friction ◽  
2021 ◽  
Author(s):  
Zonglin Pan ◽  
Qinzhao Zhou ◽  
Pengfei Wang ◽  
Dongfeng Diao
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Orthodontic Treatment ◽  
Artificial Saliva ◽  
Carbon Film ◽  
Carbon Films ◽  
Graphene Sheets ◽  
Substrate Bias ◽  
Low Friction ◽  
Substrate Bias Voltage

AbstractReducing the friction force between the commercial archwire and bracket during the orthodontic treatment in general dental practice has attracted worldwide interest. An investigation on the friction and wear behaviors of the uncoated and carbon film coated stainless steel archwires running against stainless steel brackets was systematically conducted. The carbon films were prepared at substrate bias voltages from +5 to +50 V using an electron cyclotron resonance plasma sputtering system. With increasing substrate bias voltage, local microstructures of the carbon films evolved from amorphous carbon to graphene nanocrystallites. Both static and stable friction coefficients of the archwire-bracket contacts sliding in dry and wet (artificial saliva) conditions decreased with the deposition of carbon films on the archwires. Low friction coefficient of 0.12 was achieved in artificial saliva environment for the graphene sheets embedded carbon (GSEC) film coated archwire. Deterioration of the friction behavior of the GSEC film coated archwire occurred after immersion of the archwire in artificial saliva solution for different periods before friction test. However, moderate friction coefficient of less than 0.30 sustained after 30 days immersion periods. The low friction mechanism is clarified to be the formation of salivary adsorbed layer and graphene sheets containing tribofilm on the contact interfaces. The robust low friction and low wear performances of the GSEC film coated archwires make them good candidates for clinical orthodontic treatment applications.

Heat Exchanger Options for Dry Air Cooling for the sCO2 Brayton Cycle

2017 ◽  
Author(s):  
Anton Moisseytsev ◽  
Qiuping Lv ◽  
James J. Sienicki
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cost Effective ◽  
Finned Tube ◽  
Air Cooling ◽  
Brayton Cycle ◽  
Dry Air ◽  
Air Atmosphere ◽  
Air Cooler ◽  
Forced Air

The capability to utilize dry air cooling by which heat is directly rejected to the air atmosphere heat sink is one of the benefits of the supercritical carbon dioxide (sCO2) energy conversion cycle. For the selection and analysis of the heat exchanger options for dry air cooling applications for the sCO2 cycle, two leading forced air flow design approaches have been identified and analyzed for this application; an air cooler consisting of modular finned tube air coolers; and an air cooler consisting of modular compact diffusion-bonded heat exchangers. The commercially available modular finned tube air cooler is found to be more cost effective and is selected as the reference for dry air cooling.

scholarly journals Surface modification and the friction coefficient of tetrahedral amorphous carbon films bombarded by energetic N ion

2011 ◽  
Vol 60 (6) ◽  
pp. 066804
Author(s):  
Han Liang ◽  
Chen Xian ◽  
Yang Li ◽  
Wang Yan-Wu ◽  
Wang Xiao-Yan ◽  
...  
Keyword(s):  
Surface Modification ◽  
Friction Coefficient ◽  
Amorphous Carbon ◽  
Carbon Films ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon

scholarly journals INFLUENCE OF ELECTRIC FIELD ON ADHESION AND STRUCTURE OF CONDUCTING FILMS ON DIELECTRIC SUBSTANCES

2017 ◽  
Vol 60 (8) ◽  
pp. 100 ◽  
Author(s):  
Nikolai S. Pshchelko ◽  
Ekaterina G. Vodkailo ◽  
Vladimir V. Tomaev ◽  
Boris D. Klimenkov ◽  
Veniamin L. Koshevoi ◽  
...  
Keyword(s):  
Electric Field ◽  
Dielectric Substrate ◽  
Zno Films ◽  
Electric Voltage ◽  
X Ray ◽  
Dry Air ◽  
Glass Substrates ◽  
Plasma Sputtering ◽  
Air Atmosphere ◽  
Extended Surface

Some results are provided confirming that modifying of the zinc films fabricated on glass substrates by a resulting effect of heat treatment in an atmosphere of dry air and action of cross electric field is possible. Using scanning electron microscopy (measured with the Zeiss Merlin microscope) the surface morphology of the films was studied. Also, the elemental composition of the films by micro-X-ray spectral analysis was studied. On the glass substrates, by the method of vacuum thermal evaporation, zinc films (Zn) with thickness of ~ 500 nm were obtained. In order to form ZnO films, the original films were treated at 250 °C in a dry air atmosphere, and in another case - in addition to the sample a transverse electric field with a potential of 300 V was applied. Platinum films on the silicon dioxide layer were obtained using the method of the ion-plasma sputtering. These layers were investigated by X-ray phase analysis, electron and atomic force microscopy. The thickness of platinum layers was 50 and 100 nm. During the deposition (deposition temperature – 300 °C, deposition rate - 5 nm / min), applied voltage between the platinum film and the silicon plate was 5 V. The films, obtained by applying a biasing, showed a more homogeneous fine-grained structure and a higher rate of growth than the original samples.  In this way ZnO films can be manufactured with the extended surface. The possibility of significant changes caused by electric field use in adhesion, structure and conductive properties of the coatings is discussed. The method of depositing platinum on a dielectric substrate with an additional electrostatic field is also substantiated. It is shown that the application of an electric voltage to the film leads to a significant change in the structure of the resulting coating.Forcitation:Pshchelko N.S., Vodkailo E.G., Tomaev V.V., Klimenkov B.D., Koshevoi V.L., Belorus A.O. Influence of electric field on adhesion and structure of conducting films on dielectric substances. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 100-104.

Temperature and Water Vapor Pressure Effects on the Friction Coefficient of Hydrogenated Diamondlike Carbon Films

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Pamela L. Dickrell ◽  
N. Argibay ◽  
Osman L. Eryilmaz ◽  
Ali Erdemir ◽  
W. Gregory Sawyer
Keyword(s):  
Water Vapor ◽  
Friction Coefficient ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Carbon Film ◽  
Transient Behavior ◽  
Carbon Films ◽  
Pressure Effects ◽  
Diamondlike Carbon ◽  
Gas Surface Interactions

Microtribological measurements of a hydrogenated diamondlike carbon film in controlled gaseous environments show that water vapor plays a significant role in the friction coefficient. These experiments reveal an initial high friction transient behavior that does not reoccur even after extended periods of exposure to low partial pressures of H2O and O2. Experiments varying both water vapor pressure and sample temperature show trends of a decreasing friction coefficient as a function of both the decreasing water vapor pressure and the increasing substrate temperature. Theses trends are examined with regard to first order gas-surface interactions. Model fits give activation energies on the order of 40 kJ/mol, which is consistent with water vapor desorption.

Effect of structure on the secondary electron emission of tetrahedral amorphous carbon films

Vacuum ◽  
2020 ◽  
Vol 172 ◽  
pp. 109043
Author(s):  
Yongfeng Kang ◽  
Bin Li ◽  
Jingyi Zhao ◽  
Bangzhi Ge ◽  
Ming Weng ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Carbon Films ◽  
Amorphous Carbon Films ◽  
Tetrahedral Amorphous Carbon ◽  
Effect Of Structure
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