Solid lubrication with MoS2-Ti-C films for high-vacuum applications in a nuclear fusion experimental device

2018 ◽  
Vol 70 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Shanshuang Shi ◽  
Huapeng Wu ◽  
Yuntao Song ◽  
Heikki Handroos
Keyword(s):  
High Vacuum ◽  
Ultra High Vacuum ◽  
Experimental Device ◽  
Solid Lubrication ◽  
Hybrid Coatings ◽  
Vacuum Vessel ◽  
Coating Films ◽  
Content Type ◽  
Sputtering Deposition ◽  
Inner Vessel

Purpose This paper aims to present a study on composite coating films for solid lubrication applied on the surface of bearings and gears, which are exposed to the vacuum vessel of a tokamak fusion experimental device running under ultra-high vacuum conditions. Experimental advanced superconducting tokamak is a tokamak fusion experimental device running under ultra-high vacuum conditions. To avoid polluting the inner vessel environment, solid lubrication has been applied on the surface of bearings and gears, which are exposed to the vacuum. Design/methodology/approach Anti-friction MoS2 coatings integrated with Titanium and Carbon have been developed using the multi-target magnetron sputtering deposition technique. This paper presents the comparative testing of tribological properties for three kinds of MoS2-based coating layers. Findings Based on the test results, MoS2-Ti-C coating films are supposed to be the final selection because of the better performance of friction coefficient and lubrication longevity. Originality/value Finally, the detailed information has been characterized for the hybrid coatings, which can provide some references for applications of solid lubrications under similar conditions of high vacuum and temperature.

Influences of Gases on the Tribological Properties of Pure Iron

2011 ◽  
Author(s):  
Kanao Fukuda ◽  
Joichi Sugimura
Keyword(s):  
Tribological Properties ◽  
Dry Friction ◽  
Pure Iron ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
The Other ◽  
Vacuum Vessel ◽  
Friction Coefficients ◽  
Wear Rates ◽  
Pin On Disk

In this study, trace oxygen and water as impurities in experimental gas environments were reduced to less than 10 ppb to eliminate their influences on the tribological properties. A pin-on-disk apparatus in an ultra-high vacuum vessel equipped with a gas filtering system enabled pure experimental gas environments. Dry friction tests clarified that the tribological properties of pure iron in ultra-high vacuum and argon were similar to each other. On the other hand, friction coefficients obtained in hydrogen and nitrogen were considerably lower than those obtained in ultra-high vacuum and argon. Specific wear rates of pin and disk were close to each other in ultra-high vacuum, argon and hydrogen while those took very different values in nitrogen. Hydrogen influenced the tribological properties of pure iron to some extent but the influences were not as much as that of nitrogen.

Pt/Ir/C, a new, powerful coating material for High-Resolution SEM

1990 ◽  
Vol 48 (3) ◽  
pp. 6-7
Author(s):  
Roger Wepf ◽  
Heinz Gross
Keyword(s):  
Freeze Drying ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Type I ◽  
Atmospheric Conditions ◽  
Coating Films ◽  
Hydration Shells ◽  
Probe Size ◽  
Structural Preservation ◽  
The Right

In-lens field emission SEM allows to image specimen surfaces with subnanometer resolution by collecting type I secondary electrons, with an incident electron probe size of abut 0.5 nm in diameter. To achieve such high topographic resolution on biological specimens adequate structural preservation and high resolving thin continuous coating films are necessary.Careful freeze-drying (“maintaining hydration shells”) followed by heavy metal shadowing at -250°C under ultra high vacuum conditions (UHV) allows to extract surface features ≤2 nm with TEM. TEM-shadowing films (Pt/C, Ta/W) are stabilized with a C-backing layer. Such a C-coat would blurr fine details when investigated with the SEM.At the right composition (C-content 25-40%, metal content 75-60%) only about 1.5 nm thick Pt/Ir/C-films remain three-dimensionally stable when transferred to atmospheric conditions after freeze-drying samples with macromolecular dimensions. Pt/Ir/C is made by evaporating a Pt/Ir cylinder (diameter 1.5 mm, 70% Ir) inserted into a graphite rod (diameter 2 mm).

Control of frictional force on coating films of boron nitride–copper complex in ultra high vacuum

2002 ◽  
Vol 405 (1-2) ◽  
pp. 300-303 ◽  
Author(s):  
Masahiro Goto ◽  
Akira Kasahara ◽  
Masahiro Tosa ◽  
Kazuhiro Yoshihara
Keyword(s):  
Boron Nitride ◽  
Copper Complex ◽  
Frictional Force ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Coating Films

Ge Optical Interconnects on a GaAs Surface

1994 ◽  
Vol 340 ◽  
Author(s):  
M. Dubey ◽  
G.F. McLane ◽  
K.A. Jones ◽  
R.T. Lareau ◽  
D.W. Eckart ◽  
...  
Keyword(s):  
Optical Interconnects ◽  
High Vacuum ◽  
Amorphous Film ◽  
Ultra High Vacuum ◽  
Free Carrier Absorption ◽  
Sputtering Deposition ◽  
A Value ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Carrier Absorption

ABSTRACTGermanium films were deposited on GaAs (100) substrates at temperatures between room temperature (RT) and 500°C using ultra high vacuum (UHV) E-beam and sputtering deposition methods. The Ge film deposited in UHV at 100°C was amorphous and had a flat absorbance curve over the range investigated, 4000 - 500 cm-1, with a value of 0.03 at 1000 cm1 (10μm). Films deposited by E-beam at RT and 50°C had comparably low absorbances, but they contained a peak at 830 cm-1, which was possibly due to absorption by a Ge-O bond. The amorphous film deposited at 150°C and the single crystal films deposited at 400 and 500°C by E-beam had larger absorbances caused by free carrier absorption. The amorphous Ge sputtered film deposited at RT had a relatively low absorbance, but it contained the absorption peak attributed to Ge-O. The absorbance increased dramatically when it was annealed at 400 or 500°C due to the rapid out diffusion of Ga and As through the relatively open structure.

Thin Pyrolytic Graphite Films for Electron Microscope Substrates

1971 ◽  
Vol 29 ◽  
pp. 226-227 ◽  
Author(s):  
George H. N. Riddle ◽  
Benjamin M. Siegel
Keyword(s):  
Vacuum Chamber ◽  
Pyrolytic Graphite ◽  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Graphite Substrate ◽  
Nickel Substrate ◽  
Routine Procedure ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A routine procedure for growing very thin graphite substrate films has been developed. The films are grown pyrolytically in an ultra-high vacuum chamber by exposing (111) epitaxial nickel films to carbon monoxide gas. The nickel serves as a catalyst for the disproportionation of CO through the reaction 2C0 → C + CO2. The nickel catalyst is prepared by evaporation onto artificial mica at 400°C and annealing for 1/2 hour at 600°C in vacuum. Exposure of the annealed nickel to 1 torr CO for 3 hours at 500°C results in the growth of very thin continuous graphite films. The graphite is stripped from its nickel substrate in acid and mounted on holey formvar support films for use as specimen substrates.The graphite films, self-supporting over formvar holes up to five microns in diameter, have been studied by bright and dark field electron microscopy, by electron diffraction, and have been shadowed to reveal their topography and thickness. The films consist of individual crystallites typically a micron across with their basal planes parallel to the surface but oriented in different, apparently random directions about the normal to the basal plane.

A High Voltage Electron Microscopy Study of Sub-Oxide Formation in Vanadium

1971 ◽  
Vol 29 ◽  
pp. 212-213
Author(s):  
R. H. Geiss ◽  
R. L. Ladd ◽  
K. R. Lawless
Keyword(s):  
High Vacuum ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Ultra High Vacuum ◽  
Pure Oxygen ◽  
Pressure Oxidation ◽  
High Voltage Electron Microscopy ◽  
Oxidation Study ◽  
Voltage Electron ◽  
Good Agreement

Detailed electron microscope and diffraction studies of the sub-oxides of vanadium have been reported by Cambini and co-workers, and an oxidation study, possibly complicated by carbon and/or nitrogen, has been published by Edington and Smallman. The results reported by these different authors are not in good agreement. For this study, high purity polycrystalline vanadium samples were electrochemically thinned in a dual jet polisher using a solution of 20% H2SO4, 80% CH3OH, and then oxidized in an ion-pumped ultra-high vacuum reactor system using spectroscopically pure oxygen. Samples were oxidized at 350°C and 100μ oxygen pressure for periods of 30,60,90 and 160 minutes. Since our primary interest is in the mechanism of the low pressure oxidation process, the oxidized samples were cooled rapidly and not homogenized. The specimens were then examined in the HVEM at voltages up to 500 kV, the higher voltages being necessary to examine thick sections for which the oxidation behavior was more characteristic of the bulk.

The High Resolution Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 316-317
Author(s):  
A. V. Crewe
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Resolving Power ◽  
Imaging Characteristics ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Moment

The high resolution STEM is now a fact of life. I think that we have, in the last few years, demonstrated that this instrument is capable of the same resolving power as a CEM but is sufficiently different in its imaging characteristics to offer some real advantages.It seems possible to prove in a quite general way that only a field emission source can give adequate intensity for the highest resolution^ and at the moment this means operating at ultra high vacuum levels. Our experience, however, is that neither the source nor the vacuum are difficult to manage and indeed are simpler than many other systems and substantially trouble-free.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

A Field Emission System For Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 298-299
Author(s):  
Michel Troyonal ◽  
Huei Pei Kuoal ◽  
Benjamin M. Siegelal
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Optical System ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Objective Lens ◽  
Electron Optical System ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Emission System

A field emission system for our experimental ultra high vacuum electron microscope has been designed, constructed and tested. The electron optical system is based on the prototype whose performance has already been reported. A cross-sectional schematic illustrating the field emission source, preaccelerator lens and accelerator is given in Fig. 1. This field emission system is designed to be used with an electron microscope operated at 100-150kV in the conventional transmission mode. The electron optical system used to control the imaging of the field emission beam on the specimen consists of a weak condenser lens and the pre-field of a strong objective lens. The pre-accelerator lens is an einzel lens and is operated together with the accelerator in the constant angular magnification mode (CAM).

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