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.

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.

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.

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

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.

Thermally Induced Superlow Friction of DLC Films in Ambient Air

2018 ◽  
Vol 37 (8) ◽  
pp. 725-731 ◽  
Author(s):  
Qunfeng Zeng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ambient Air ◽  
Friction Model ◽  
Repulsive Force ◽  
Hydroxyl Group ◽  
Thermally Induced ◽  
X Ray ◽  
Thermally Activated ◽  
Charged Interface ◽  
Positively Charged

AbstractThermally induced superlow friction (0.008) of diamond-like carbon (DLC) films was achieved in ambient air in the present work. Raman and XPS (X-ray Photoelectron Spectroscopy) measurements and analyses show that superlow friction of the annealed DLC films is involved in the transformation of sp3 to sp2 hybridized carbon during annealing and the tribochemical reactions during sliding. The thermally activated graphitization and oxidation of the annealed DLC films in ambient air is beneficial to form the positively charged interface and achieve the stable superlow friction. A friction model was developed and applied to explain superlow friction, which is attributed to Van de Waals force between graphite layers and the repulsive force between hydroxyl group of graphite oxide and hydrogen terminated DLC films surface.

The Effect of CNT Content on the Tribological Properties of CNTs Doped Diamond-Like Carbon Films

2015 ◽  
Vol 642 ◽  
pp. 231-235
Author(s):  
Che Hung Wei ◽  
Jui Feng Yang ◽  
Chao I Wang
Keyword(s):  
Friction Coefficient ◽  
Critical Load ◽  
Internal Stress ◽  
Tribological Properties ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Element Analysis ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Diamond-like carbon (DLC) films is useful in many applications. To improve the tribological properties in DLC, we spin coat the multi-walled carbon nanotubes (CNTs) with different solution on (100) silicon. DLC was deposited by plasma enhanced chemical vapor deposition (PECVD) with C2H2and H2. The results show that the ID/IGratio is increasing with higher CNTs content while the friction coefficient and critical load are decreasing with larger CNTs contents. The decreasing friction coefficient results from graphitation on the surface due to higher sp2content. The decreasing critical load is attributed to higher internal stress. The effect of friction coefficient and CNT concentration on stress distribution is studied by a nanoscratch finite element analysis. The results indicate that low friction coefficient and high CNT concentration will reduce the stress magnitude in the film. Therefore, the decreasing friction coefficient in CNT doped DLC film with increasing CNT concentration should reduce stress in the film and is good for adhesion. The discrepancy between friction coefficient and critical load is explained in terms of high internal stress during deposition. A surface treatment on CNT before deposition to reduce internal stress is currently under investigation.

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