Friction and Wear Micromechanisms of Amorphous Carbon Thin Films

1997 ◽  
Vol 119 (4) ◽  
pp. 823-829 ◽  
Author(s):  
B. Wei ◽  
K. Komvopoulos
Keyword(s):  
Amorphous Carbon ◽  
Friction And Wear ◽  
Carbon Film ◽  
Film Surface ◽  
Carbon Films ◽  
Film Structure ◽  
Friction Behavior ◽  
Surface Microtopography ◽  
Carbon Overcoats ◽  
Magnetic Recording Heads

The friction and wear micromechanisms of amorphous hydrogenated carbon films were investigated experimentally using commercially available thin-film rigid disks with sputtered carbon overcoats and Al2O3TiC magnetic recording heads. Continuous sliding tests demonstrated the existence of two distinct friction and wear regimes characterized by different dominant micromechanisms. Scanning electron microscopy and Raman spectroscopy revealed that the evolution of friction in the first regime is due to changes of the surface microtopography and the film structure from amorphous carbon to polycrystalline graphite. Atomic force microscopy showed that the topography changes result from asperity nanofracture leading to the gradual removal of carbon material and the generation of ultrafine wear debris. The friction behavior in the second regime is due to various wear processes arising on the carbon film surface. High friction promotes surface micropitting and the formation of significantly deeper and wider texture marks. The erratic fluctuations of the friction force and microplowing of the carbon film at steady state are attributed to the relatively large wear particles generated by micropitting.

Optical and electronic properties of nitrogen-implanted diamond-like carbon films

1994 ◽  
Vol 9 (1) ◽  
pp. 85-90 ◽  
Author(s):  
G.L. Doll ◽  
J.P. Heremans ◽  
T.A. Perry ◽  
J.V. Mantese
Keyword(s):  
Amorphous Carbon ◽  
Carbon Film ◽  
Film Surface ◽  
Carbon Films ◽  
Localized States ◽  
Diamond Like Carbon ◽  
Nitrogen Implantation ◽  
Electrical Measurements ◽  
Nitrogen Ion ◽  
Ion Implanted

Optical and electrical measurements on nitrogen ion-implanted diamond-like carbon films are presented. Raman scattering measurements, which probe the crystallinity of the film surface, indicate that nitrogen implantation reduces the finite crystallographic order in the pristine carbon films. The absence of molecular vibrations in the infrared absorption spectra of the films argues against a polymeric structure of the ion-implanted films. Spectroscopic ellipsometry experiments determine the change in the optical constants of the carbon film due to nitrogen implantation. Electrical de conductivity measurements are interpreted within the framework of a schematic density of states picture of graphitic τ-electrons in an amorphous carbon system. Taken collectively, the optical and electrical measurements suggest that nitrogen implantation increases the density of localized states within the 1.5 eV bandgap of the quasi-amorphous carbon film, thereby reducing the bandgap and increasing the conductivity of the nitrogen-implanted films.

scholarly journals Tribocatalytically-activated formation of protective friction and wear reducing carbon coatings from alkane environment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Asghar Shirani ◽  
Yuzhe Li ◽  
Osman Levent Eryilmaz ◽  
Diana Berman
Keyword(s):  
Amorphous Carbon ◽  
Steel Substrate ◽  
Carbon Film ◽  
Substantial Reduction ◽  
Liquid Hydrocarbon ◽  
Shear Stresses ◽  
Friction Behavior ◽  
Uncoated Steel ◽  
Protective Films ◽  
Wear Coatings

AbstractMinimizing the wear of the surfaces exposed to mechanical shear stresses is a critical challenge for maximizing the lifespan of rotary mechanical parts. In this study, we have discovered the anti-wear capability of a series of metal nitride-copper nanocomposite coatings tested in a liquid hydrocarbon environment. The results indicate substantial reduction of the wear in comparison to the uncoated steel substrate. Analysis of the wear tracks indicates the formation of carbon-based protective films directly at the sliding interface during the tribological tests. Raman spectroscopy mapping of the wear track suggests the amorphous carbon (a-C) nature of the formed tribofilm. Further analysis of the tribocatalytic activity of the best coating candidate, MoN-Cu, as a function of load (0.25–1 N) and temperature (25 °C and 50 °C) was performed in three alkane solutions, decane, dodecane, and hexadecane. Results indicated that elevated temperature and high contact pressure lead to different tribological characteristics of the coating tested in different environments. The elemental energy dispersive x-ray spectroscopy analysis and Raman analysis revealed formation of the amorphous carbon film that facilitates easy shearing at the contact interface thus enabling more stable friction behavior and lower wear of the tribocatalytic coating. These findings provide new insights into the tribocatalysis mechanism that enables the formation of zero-wear coatings.

Structural Analysis of Boron- and Nitrogen-Doped Amorphous Carbon Films from Bio-Product

2020 ◽  
Vol 860 ◽  
pp. 190-195
Author(s):  
Irma Septi Ardiani ◽  
Khoirotun Nadiyyah ◽  
Anna Zakiyatul Laila ◽  
Sarayut Tunmee ◽  
Hideki Nakajima ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Amorphous Carbon ◽  
Carbon Film ◽  
Carbon Films ◽  
Basic Material ◽  
Carbon Phase ◽  
Amorphous Carbon Film ◽  
Amorphous Carbon Films ◽  
Nitrogen Doped ◽  
P Type

Amorphous carbon films have been explored and used in a wide variety of applications. With the n-type and p-type amorphous carbon film, it can be used to make p-n junctions for solar cells. This research aims to study the structure of boron- and nitrogen-doped amorphous carbon (a-C:B and a-C:N) films. This research uses the basic material of bio-product from palmyra sugar to form amorphous carbon. Amorphous carbon was synthesized by heating the palmyra sugar at 250°C. The results of XRD showed that the doped films produce an amorphous carbon phase. PES was used to analyze the bonding state of dopants in the sample. B4C, BC3, and BC2O bonds formed in a-C:B, while pyridine and pyrrolic formed in a-C:N.

Molecular Dynamics Simulations of Structures of Amorphous Carbon Films via Deposition

2011 ◽  
Vol 194-196 ◽  
pp. 2220-2224
Author(s):  
Hui Qing Lan ◽  
Zheng Ling Kang
Keyword(s):  
Molecular Dynamics ◽  
Amorphous Carbon ◽  
Growth Dynamics ◽  
Carbon Films ◽  
Film Structure ◽  
Dynamics Simulation ◽  
Carbon Ions ◽  
Amorphous Carbon Films ◽  
Dynamics Simulations ◽  
The Impact

The growth of amorphous carbon films via deposition is investigated using molecular dynamics simulation with a modified Tersoff potential. The impact energy of carbon atoms ranges from 1 to 50 eV and the temperature of the diamond substrate is 300 K. The effects of the incident energy on the growth dynamics and film structure are studied in a detail. Simulation results show that the mobility of surface atoms in the cascade region is enhanced by impacting energetic carbon ions, especially at moderate energy, which favors the growth of denser and smoother films with better adhesion to the substrate. Our results agree qualitatively with the experimental observation.

The Effects of Film Structure and Surface Hydrogen on the Properties of Amorphous Carbon Films

2003 ◽  
Vol 107 (40) ◽  
pp. 11082-11090 ◽  
Author(s):  
G. T. Gao ◽  
Paul T. Mikulski ◽  
Ginger M. Chateauneuf ◽  
Judith A. Harrison
Keyword(s):  
Amorphous Carbon ◽  
Carbon Films ◽  
Film Structure ◽  
Amorphous Carbon Films ◽  
Surface Hydrogen

Formation of diamondlike nanocrystallites in amorphous carbon films synthesized by radio-frequency sputtering

2008 ◽  
Vol 23 (3) ◽  
pp. 700-703 ◽  
Author(s):  
D. Wan ◽  
K. Komvopoulos
Keyword(s):  
Carbon Atom ◽  
Radio Frequency ◽  
Amorphous Carbon ◽  
Rf Sputtering ◽  
Film Surface ◽  
Carbon Films ◽  
Fast Fourier Transformation ◽  
Process Conditions ◽  
Tem Analysis ◽  
Radio Frequency Sputtering

Transmission electron microscopy (TEM) and fast Fourier transformation (FFT) analysis were used to examine the microstructures of amorphous carbon (a-C) films deposited on Si(100) by radio-frequency (rf) sputtering without magnetron. TEM analysis revealed that a-C films synthesized under certain deposition conditions contained randomly dispersed nanocrystallites ∼35 Å in size. FFT results indicated that the nanocrystallites possessed diamondlike cubic structures with their close-packed {111} planes parallel to the film surface. The formation of diamondlike nanocrystallites is attributed to metastable carbon atom clusters of trigonal carbon hybridization that were sputtered off from the graphite target under certain process conditions. Cluster distortion upon deposition onto the growing film surface by the bombarding Ar+ ions promoted tetrahedral carbon atom hybridization and, possibly, epitaxial growth of diamondlike nanocrystallites for a short duration.

Effects of Amorphous Carbon Films on the Performance of Porous Silicon Electroluminescence

2002 ◽  
Vol 737 ◽  
Author(s):  
Bernard Gelloz ◽  
Nobuyoshi Koshida
Keyword(s):  
Porous Silicon ◽  
Amorphous Carbon ◽  
Chemical Stability ◽  
Indium Tin Oxide ◽  
Carbon Film ◽  
Carbon Films ◽  
Positive Effects ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
The Stability

ABSTRACTEfficient electroluminescence (EL) is obtained at low operating voltages (<3 V) from n+-type silicon- electrochemically oxidized thin nanocrystalline porous silicon (PS)-amorphous carbon-Indium tin oxide (ITO) junctions. The effects of a few nanometer thick amorphous carbon film between PS and ITO on the EL characteristics have been investigated. The carbon film enhances the stability. The EL efficiency is improved due to a reduction of current density and an increase in EL intensity. In addition, the reproducibility from device to device is very much improved by the carbon film. The enhancement in stability should originate from the capping of PS by the carbon film and the high chemical stability of carbon and Si-C bonds, which should prevent PS oxidation. The carbon film acts as an efficient buffer layer between PS and ITO, resulting in enhanced mechanical, electrical and chemical stability of the top contact and providing high reproducibility. The thin carbon film has only positive effects on all the EL characteristics. This is a very important step towards application.

scholarly journals Electrical Conduction Properties of Hydrogenated Amorphous Carbon Films with Different Structures

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2355
Author(s):  
Masashi Tomidokoro ◽  
Sarayut Tunmee ◽  
Ukit Rittihong ◽  
Chanan Euaruksakul ◽  
Ratchadaporn Supruangnet ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Amorphous Carbon ◽  
Electrical Conduction ◽  
Conduction Mechanism ◽  
Carbon Films ◽  
Film Structure ◽  
Hydrogen Atoms ◽  
Hydrogenated Amorphous Carbon ◽  
Electrical Conduction Mechanism ◽  
Hydrogenated Amorphous

Hydrogenated amorphous carbon (a-C:H) films have optical and electrical properties that vary widely depending on deposition conditions; however, the electrical conduction mechanism, which is dependent on the film structure, has not yet been fully revealed. To understand the relationship between the film structure and electrical conduction mechanism, three types of a-C:H films were prepared and their film structures and electrical properties were evaluated. The sp2/(sp2 + sp3) ratios were measured by a near-edge X-ray absorption fine structure technique. From the conductivity–temperature relationship, variable-range hopping (VRH) conduction was shown to be the dominant conduction mechanism at low temperatures, and the electrical conduction mechanism changed at a transition temperature from VRH conduction to thermally activated band conduction. On the basis of structural analyses, a model of the microstructure of a-C:H that consists of sp2 and sp3-bonded carbon clusters, hydrogen atoms and dangling bonds was built. Furthermore, it is explained how several electrical conduction parameters are affected by the carrier transportation path among the clusters.

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