Probing the frictional properties of sulfur-doped diamond-like carbon films under high vacuum by first-principles calculations

2019 ◽  
Vol 481 ◽  
pp. 1483-1489 ◽  
Author(s):  
Renhui Zhang ◽  
Jibin Pu ◽  
Yingchang Yang ◽  
Lei Guo ◽  
Junjun Wang
Keyword(s):  
First Principles ◽  
High Vacuum ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
First Principles Calculations ◽  
Frictional Properties

Large Area Surface Treatment by Ion Beam Technology

1996 ◽  
Vol 438 ◽  
Author(s):  
R. L. C. Wu ◽  
W. Lanter
Keyword(s):  
Ion Beam ◽  
High Vacuum ◽  
Polycrystalline Diamond ◽  
Carbon Films ◽  
Ultra High Vacuum ◽  
Diamond Like Carbon ◽  
Chemical Compositions ◽  
Rf Power ◽  
Large Area ◽  
Ion Energy

AbstractAn ultra high vacuum ion beam system, consisting of a 20 cm diameter Rf excilted (13.56 MHz) ion gun and a four-axis substrate scanner, has been used to modify large surfaces (up to 1000 cm2) of various materials, including; infrared windows, silicon nitride, polycrystalline diamond, 304 and 316 stainless steels, 440C and M50 steels, aluminum alloys, and polycarbonates; by depositing different chemical compositions of diamond-like carbon films. The influences of ion energy, Rf power, gas composition (H2/CH4 , Ar/CH4 and O2/CH4/H2), on the diamond-like carbon characteristics has been studied. Particular attention was focused on adhesion, environmental effects, IR(3–12 μm) transmission, coefficient of friction, and wear factors under spacelike environments of diamond-like carbon films on various substrates. A quadrupole mass spectrometer was utilized to monitor the ion beam composition for quality control and process optimization.

Mechanical Properties of Laser Processed Diamond-Like Carbon Films

1995 ◽  
Vol 397 ◽  
Author(s):  
Ashok Kumar ◽  
R. B. Inturi ◽  
Y. Vohra ◽  
U. Ekanayake ◽  
N. Shu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Pyrolytic Graphite ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Chemical Properties ◽  
High Hardness ◽  
Deposition Process ◽  
Carbon Films ◽  
Diamond Like Carbon

ABSTRACTDiamond-like carbon (DLC) films have a unique combination of physical and chemical properties such as high hardness, optical transparency, low coefficient of friction and chemical inertness. A pulsed laser (248 nm) has been used to ablate a pyrolytic graphite target to deposit DLC films on Si (100) and 7059 Corning glass substrates. The deposition was carried out in high vacuum (≤ 10−6 Torr) at different temperatures ranging from room temperature to 400°C. The films were characterized by x-ray diffraction, scanning electron microscope, and Raman spectroscopie techniques. The mechanical properties (hardness and Young's modulus) of these films were characterized by nanoindentation. We have found that the films deposited at room temperature and 100°C show the characteristic features of DLC films and have the better hardness and modulus properties compared to the films fabricated at higher temperatures, which transform into amorphous carbon. Correlations of pulsed laser deposition process parameters with the properties of deposited DLC films will be discussed in this paper.

In situ Monitoring of the Effects of Gas Mixtures on Ion Beam Depositions of Diamond-Like Carbon Films

1997 ◽  
Vol 502 ◽  
Author(s):  
R. L. C. Wu ◽  
W. Lanter ◽  
R. Monreal ◽  
P. B. Kosel ◽  
K. Miyoshi
Keyword(s):  
Oxygen Concentration ◽  
Mass Spectrometer ◽  
High Vacuum ◽  
Gas Mixtures ◽  
Carbon Films ◽  
Ion Source ◽  
Ultra High Vacuum ◽  
In Situ Monitoring ◽  
Diamond Like Carbon ◽  
Measuring Device

ABSTRACTA quadrupole mass spectrometer and a total ion-current measuring device have been utilized to monitor the ion compositions of gas mixtures of CH4/H2 and CH4/H2/O2 during the deposition for quality control and process optimization. An ultra high vacuum system using a 20 cm diameter RF excited (13.56 MIfz) ion gun and a four-axis substrate scanner has been developed for deposition of diamond-like carbon films for electrical, optical, and tribological applications. At a constant RF power of 179W, the mass spectra of gas mixture CH4/H2 (1:2.5) showed the most abundant ion is CH3+. Addition of O2 to the ion source has been found to affect the adhesion, deposition rate, and physical and chemical properties of the DLC films. By use of a mass spectrometer with and without the electron beam, the degree of ionization of CH4 was calculated to be about 10%. As the concentration of O2 was increased, all hydrocarbon ions decreased and H3O+ increased, resulting in a decrease in the film growth rate and an increase in etching of Si and glass substrates. In general, the optical bandgap, adsorption coefficients and refractive index decreased as oxygen concentration increased. Raman spectra showed the G-peak position shifted toward the graphitic peak with narrow peak width as oxygen concentration increased. At ultra high vacuum, the coefficient of friction increased with increased adhesion on substrates as oxygen was increased.

Transitory Metastable Phases in Refractory Metals-Based Systems Solidified by Drop-Tube Processing: A First-Principles Approach

1999 ◽  
Vol 580 ◽  
Author(s):  
C. Berne ◽  
A. Pasturel ◽  
M. Sluiter ◽  
B. Vinet
Keyword(s):  
Structural Stability ◽  
First Principles ◽  
High Vacuum ◽  
Refractory Metals ◽  
Solidification Path ◽  
Metastable Phases ◽  
Ultra High Vacuum ◽  
Drop Tube ◽  
First Principles Calculations ◽  
Σ Phase

AbstractThe solidification path of highly undercooled refractory metals and their alloys solidified in a ultra high vacuum drop-tube is shown to involve transitory metastable phases. First-principles calculations of structural stability are used to determine the possibility of obtaining metastable phases in these systems, with a view to relate this metastability with the site occupation in the σ phase in the case of the ReTa system.

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