Solid Lubricating Films for Extreme Environments

1988 ◽  
Vol 140 ◽  
Author(s):  
Irwin L. Singer
Keyword(s):  
Material Selection ◽  
Multilayer Coating ◽  
Composite Films ◽  
Extreme Environments ◽  
Carbon Films ◽  
Friction Coefficients ◽  
Film Adhesion ◽  
Scientific Principles ◽  
Recent Developments ◽  
Deposition Processes

AbstractAdvances in solid lubricating films for vacuum and high temperature applications are reviewed. Traditional lubricants (e.g. graphite and dichalcogenides) are being improved and new lubricating materials (e.g. amorphous carbons) are being discovered with the aid of recent developments in deposition processes and surface analytical methods. Ion bombardmenttreatments have increased film adhesion, lowered friction coefficients and enhanced the wearlife of MoS2films, as well as created new forms of lubricating carbons (amorphous, polymeric and diamond-like). Composite films and multilayer coating treatments are providing extra protection for surface and films against environmental degradation. Ultralow friction coefficients (<0.01) have been achieved with MoS 2 as well as diamond-like carbon films. Material selection, in some cases (e.g. thin metal films), can nowbe made basedon scientific principles, although many tribomaterials are still being developed by trialand error methods.

Vapor deposition processes for amorphous carbon films withsp3fractions approaching diamond

1991 ◽  
Vol 70 (3) ◽  
pp. 1706-1711 ◽  
Author(s):  
Jerome J. Cuomo ◽  
David L. Pappas ◽  
John Bruley ◽  
James P. Doyle ◽  
Katherine L. Saenger
Keyword(s):  
Amorphous Carbon ◽  
Vapor Deposition ◽  
Carbon Films ◽  
Amorphous Carbon Films ◽  
Deposition Processes

scholarly journals Low Friction at the Nanoscale of Hydrogenated Fullerene-Like Carbon Films

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 643
Author(s):  
Zhao Liu ◽  
Yongfu Wang ◽  
Thilo Glatzel ◽  
Antoine Hinaut ◽  
Junyan Zhang ◽  
...  
Keyword(s):  
Wear Debris ◽  
Carbon Films ◽  
Surface Structures ◽  
Nanometer Scale ◽  
Friction Force Microscopy ◽  
Low Friction ◽  
Friction Coefficients ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Friction Regime

Friction force microscopy experiments at the nanometer scale are applied to study low friction of hydrogenated fullerene-like carbon films. The measured friction coefficients indicate that lower hydrogen concentration during preparation is beneficial to enter the low friction regime, especially in combination with only methane as precursor. Furthermore, two regions are found with distinct friction coefficients and surface roughnesses related to different surface structures. One is rich in amorphous carbon and the other is rich in fullerene-like carbon, dispersed on the same surface. Transmission electron microscopy and Raman spectroscopy images verify this observation of the two separated structures, especially with the extracted fullerene-like structures in the wear debris from macro friction experiments. It is speculated that hydrogen may tend to impair the growth of fullerene-like carbon and is therefore detrimental for lubricity.

Characterization and Tribological Properties of Nanostructured Copper/Carbon Composite Films Prepared by Microwave Plasma-Assisted Dual Deposition Processes

2002 ◽  
Vol 750 ◽  
Author(s):  
François Thiery ◽  
Yves Pauleau ◽  
Jacques Pelletier
Keyword(s):  
Amorphous Carbon ◽  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Composite Films ◽  
Chemical Vapor ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Carbon Films ◽  
Radius Of Curvature

ABSTRACTNanocrystalline copper/hydrogenated amorphous carbon films have been deposited on Si substrates at the floating potential using a distributed electron cyclotron resonance microwave plasma reactor. In this deposition technique, the microwave plasma-enhanced chemical vapor deposition process of carbon from argon-methane or argon-acetylene mixtures of various compositions was associated with the sputter deposition of copper from a copper target. The total pressure was fixed at 0.13 Pa. For deposition, the substrates mounted on a water-cooled substrate holder were maintained at ambient temperature. The composition of films determined by Rutherford backscattering spectroscopy, energy recoil detection analyses and nuclear reaction analyses was investigated as a function of the gas phase composition. The structure of films was identified by X-ray diffraction (XRD) techniques and the size of copper crystallites incorporated in the amorphous carbon matrix was deduced from XRD data. The magnitude of residual stresses developed in these films was calculated from the radius of curvature of film/substrate samples determined by profilometry. The residual stress values were found to be nearly independent on the composition of films and deposition parameters.

Modification and Study of Polymer Films Using High Energy Ion Beams

1983 ◽  
Vol 25 ◽  
Author(s):  
T. Venkatesan
Keyword(s):  
Polymer Films ◽  
Ion Beam ◽  
Composite Films ◽  
High Energy ◽  
Carbon Films ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Inorganic Composites ◽  
Yield Information ◽  
High Energy Ions

ABSTRACTRecent results on the effects of high energy ion beam irradiation in polymer films are reviewed in this paper. High energy ions (>10 keV/amu) deposit a large amount of energy (∼several cV/atom) in ionizing the electrons of the target atoms. This results in significant destruction of bonds in the films as a result of which polymers undergo rapid dissociation. Using a quadrupole mass spectrometer the study of transient emission of molecular species produced by an ion pulse has been shown to yield information about the diffusion and reaction kinetics of various molecules in the polymer. The fact that polymers undergo dissociation and those atoms which form volatile species are selectively depleted from the film could be utilized in producing useful inorganic composites by ion bombardment of polymers. For example, hard SiC composite films have been produced by ion beam irradiation of organo-silicon polymers. Eventually, polymer dissociation leads to a predominately carbon containing film which exhibits interesting electronic transport properties. Experiments on ion irradiated, pure carbon films indicate that a metallic form of carbon is produced from the polymer films at high irradiation doses.

scholarly journals Light Scattering by Pure Water and Seawater: Recent Development

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiaodong Zhang ◽  
Lianbo Hu
Keyword(s):  
Light Scattering ◽  
Pure Water ◽  
Critical Role ◽  
Extreme Environments ◽  
Electrolyte Solutions ◽  
Ocean Optics ◽  
Depolarization Ratio ◽  
Spectral Absorption ◽  
Molecular Scattering ◽  
Recent Developments

Light scattering by pure water and seawater is a fundamental optical property that plays a critical role in ocean optics and ocean color studies. We briefly review the theory of molecular scattering in liquid and electrolyte solutions and focus on the recent developments in modeling the effect of pressure, extending to extreme environments, and evaluating the effect of salinity on the depolarization ratio. We demonstrate how the modeling of seawater scattering can be applied to better understand spectral absorption and attenuation of pure water and seawater. We recommend future efforts should be directed at measuring the polarized components of scattering by pure water over a greater range of wavelengths, temperature, salinity, and pressure to constrain and validate the model and to improve our knowledge of the water’s depolarization ratio.

scholarly journals Spontaneous formation of multilayer refractory carbide coatings in a molten salt media

2021 ◽  
Vol 118 (18) ◽  
pp. e2100663118
Author(s):  
Loic Constantin ◽  
Lisha Fan ◽  
Mathilde Pouey ◽  
Jérôme Roger ◽  
Bai Cui ◽  
...  
Keyword(s):  
Molten Salt ◽  
Multilayer Coating ◽  
Extreme Environments ◽  
Extreme Temperature ◽  
Industrial Applications ◽  
Great Promise ◽  
Refractory Carbide ◽  
High Quality ◽  
Refractory Coating ◽  
Carbide Coatings

Refractory materials hold great promise to develop functional multilayer coating for extreme environments and temperature applications but require high temperature and complex synthesis to overcome their strong atomic bonding and form a multilayer structure. Here, a spontaneous reaction producing sophisticated multilayer refractory carbide coatings on carbon fiber (CF) is reported. This approach utilizes a relatively low-temperature (950 °C) molten-salt process for forming refractory carbides. The reaction of titanium (Ti), chromium (Cr), and CF yields a complex, high-quality multilayer carbide coating composed of 1) Cr carbide (Cr3C2), 2) Ti carbide, and 3) Cr3C2 layers. The layered sequence arises from a difference in metal dissolutions, reactions, and diffusion rates in the salt media. The multilayer-coated CFs act as a permeable oxidation barrier with no crystalline degradation of the CFs after extreme temperature (1,200 °C) and environment (oxyacetylene flame) exposure. The synthesis of high-quality multilayer refractory coating in a fast, efficient, easy, and clean manner may answer the need for industrial applications that develop cheap and reliable extreme environment protection barriers.

Comparison of Energetic Carbon Deposition Processes for Use As Ultra-Thin Disk Overcoats

2001 ◽  
Author(s):  
Richard L. White ◽  
Bing K. Yen ◽  
Jan-Ulrich Thiele ◽  
Hans-Herman Schneider ◽  
James H. Rogers ◽  
...  
Keyword(s):  
Carbon Deposition ◽  
Ion Beam ◽  
Scratch Resistance ◽  
Carbon Films ◽  
Maximum Hardness ◽  
Scratch Testing ◽  
Deposition Processes ◽  
Cathodic Arc ◽  
Nitrogen Additions ◽  
Deposition Conditions

Abstract Three different processes, Plasma Enhanced CVD (PECVD), Ion Beam (IB), and Cathodic Arc (CA) have been used to deposit highly energetic carbon films in the 2–10 nm thickness range in commercial, high throughput disk manufacturing tools. The deposition conditions used are typical of those required for disk manufacturing. Raman spectroscopy, I-V measurements, nanoindentation, and AFM based scratch testing have been used to characterize the structural, electrical, and mechanical properties of the films. The measured maximum hardness for the PECVD and IBD films are 28 and 25 GPa, respectively, and found to be influenced by the hardness of the softer substrates for the 70–120nm films available for measurement. The scratch resistance of the CAC films is ∼2× the scratch resistance of the IBD films and 25% greater than the PECVD films. Addition of nitrogen to the films produced by both the PECVD and IB techniques reduces the hardness of the films. Both the Raman and I-V data suggest increasing concentrations of sp2 bonding result from these nitrogen additions.

Preparation of conductive carbon films from polyacrylonitrile/graphene oxide composite films by thermal treatment

2018 ◽  
Vol 58 ◽  
pp. 87-91 ◽  
Author(s):  
Ga Young Baek ◽  
Hwa Su Lee ◽  
Jin-Mook Jung ◽  
In-Tae Hwang ◽  
Junhwa Shin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Thermal Treatment ◽  
Composite Films ◽  
Carbon Films ◽  
Oxide Composite
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