Surface composition variation and high-vacuum performance of DLC/ILs solid–liquid lubricating coatings: Influence of space irradiation

2012 ◽  
Vol 258 (20) ◽  
pp. 8289-8297 ◽  
Author(s):  
Xiufang Liu ◽  
Liping Wang ◽  
Jibin Pu ◽  
Qunji Xue
Keyword(s):  
Surface Composition ◽  
High Vacuum ◽  
Composition Variation ◽  
Solid Liquid

Novel Morphology of Voids in Single-Quasicrystalline Icosahedral Al70.5Pd21.0Mn8.5

1998 ◽  
Vol 53 (8) ◽  
pp. 679-683 ◽  
Author(s):  
Y. Waseda ◽  
S. Suzuki ◽  
K. Urbanb
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Surface Composition ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Chemical Surface ◽  
Habit Planes ◽  
Scanning Electron

Abstract This paper deals with the morphology and surface chemistry of faceted voids existing in singlequasicrystalline icosahedral Al70.5Pd21.0Mn8.5. By observation with a scanning electron microscope of surfaces obtained by cleavage of the quasicrystal, the habit planes of the dodecahedral voids were identified. The chemical surface composition of the void surface was determined by Auger electron spectroscopy after cleavage in ultra-high vacuum.

A Comparison of the Surface Composition of Solid and Liquid Alloys

1986 ◽  
Vol 83 ◽  
Author(s):  
J. A. Barnard ◽  
P. Wynblatt ◽  
William C. Johnson ◽  
W.W. Mullins
Keyword(s):  
Liquidus Temperature ◽  
Surface Composition ◽  
Solute Segregation ◽  
Two Phase ◽  
Free Surfaces ◽  
Scanning Auger Microprobe ◽  
Liquid States ◽  
Solid Liquid ◽  
Solid And Liquid States

ABSTRACTThe surface compositions of three In-Pb alloys (1.42a/o Pb, 3.07a/o Pb, and 5.86a/o Pb) have been obtained as a function of temperature in both solid and liquid states using a scanning Auger microprobe. All data were obtained at temperature, from equilibrated samples in a region of about fifty degrees on either side of the liquidus temperature. Lead was found to be the segregating component in all cases. From these measurements, the heat of segregation has been calculated for all alloys in both states. In each alloy the magnitude of the heat of segregation declines significantly on melting although the absolute surface compositions are found to be continuous across the two phase solid-liquid field. These results are interpreted in the light of current segregation theories. Particular attention is paid to the role of elastic effects on solute segregation to free surfaces.

The Influence of Implantation Conditions and Target Orientation in High Dose Implantation of Al+ into Si

1983 ◽  
Vol 27 ◽  
Author(s):  
F. Nam-Avar ◽  
J. I. Budnick ◽  
A. Fasihuddin ◽  
H. C. Hayden ◽  
D. A. Pease ◽  
...  
Keyword(s):  
Dose Rate ◽  
Surface Composition ◽  
High Vacuum ◽  
High Dose Rate ◽  
Ultra High Vacuum ◽  
High Dose ◽  
Polycrystalline Structure ◽  
Rutherford Back Scattering ◽  
Near Surface ◽  
Projected Range

ABSTRACTWe report the preliminary results of a study to determine the dependence of the near surface composition and structure on total dose, dose rate, vacuum condition and substrate orientation for Al implantation into Si (111) and Si (100) with doses up to 2 × 10l8 ions/cm2. Our studies include the results of Rutherford Back Scattering (RBS), Auger Electron Spectroscopy (AES) and x-ray diffraction measurements on samples implanted with a 100 keV energy in a diffusion pumped vacuum (DPV) system (10−6 Torr) with and without a LN2 trap and in an ultra high vacuum (UHV) system (2–4) x 10−8 Torr.Results of high dose rate (50 μA/cm2 ) implantation into Si (111) in an untrapped DPV system indicate that Al segregates with a preferred (111) orientation. For a dose of 1 × 1018 ions/cm2 the surface is Al-rich to a depth of 2500Å while for lower doses the surface is silicon-rich. A carbon build-yp occurred for samples prepared by low dose rate (5 μA/cm2 ) implantation. However, no Al segregation could be observed for doses of less than 1018 ions/cm2 . A similar behavior has been observed for Si (100) except that Al segregation occurs with a polycrystalline structure. Moreover, the segregated Al is present at depths greater than the projected range.When implantation was carried out in a DPV system with a LN2 trap, no carbon peaks could be observed by RBS regardless of the dose rate. For these conditions, as well as for the implantation of Al in an UHV system, we find Al segregation with a polycrystalline structure independent of the dose rates and target orientations we used. Al is observed at a depth greater by a factor of two than the expected value from the Rpcalculations. The Al depth penetration increases with the dose of implantation.

New Preparation Method For Liquid Alloy Surfaces and Their Characterization by Electron Spectroscopy

1986 ◽  
Vol 83 ◽  
Author(s):  
G. Indlekofer ◽  
P. Oelhafen ◽  
H.- J. Güntherodt
Keyword(s):  
Photoelectron Spectroscopy ◽  
Liquid State ◽  
Electron Spectroscopy ◽  
Surface Composition ◽  
Liquid Metals ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Valence Electron Structure ◽  
Composition Segregation ◽  
Liquid Surfaces

ABSTRACTSurface investigations of liquid metals in ultra-high vacuum are scarce as compared with solid state studies, mainly because of experimental difficulties of preparing atomically clean liquid surfaces. A new technique has been developed in order to prepare clean liquid metal surfaces. According to the characterization with electron spectroscopy it proved to be an effective way to obtain high purity liquid surfaces and hence offers the possibility to study a variety of metals and alloys in the liquid state.Information about the surface composition, segregation properties and its purity in the liquid state and the valence electron structure has been obtained by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS, respectively). Exciting new insights in the electronic structure of various liquid alloys such as Au-Si, Cu-Sn, Ga-Sn and TI-Bi have been obtained from these measurements.

Surface Chemical Analysis of Nanoparticles for Commercial Products and Devices

2013 ◽  
Vol 1533 ◽  
Author(s):  
Marie-Isabelle Baraton
Keyword(s):  
Chemical Composition ◽  
Surface Chemistry ◽  
Surface Analysis ◽  
Surface Composition ◽  
High Vacuum ◽  
Surface Reactivity ◽  
Ultra High Vacuum ◽  
Ambient Atmosphere ◽  
Surface Chemical ◽  
Surface Chemical Composition

ABSTRACTAmongst the list of the measurands specific to nanoparticles, size and shape definitely matter but surface chemistry is also often cited. While it is now largely recognized that surface composition, structure and reactivity are perhaps the dominant parameters controlling properties of nanoparticles, surface chemistry is one of the key characteristics of nanoparticles which is seldom or inappropriately evaluated, as it has been identified by international organizations (such as ISO, BIPM or CEN). The usual techniques for surface analysis of materials often require ultra-high vacuum (UHV) conditions and are hardly applicable to nanoparticles. Moreover, because the surface chemical composition and reactivity are dependent on the environmental conditions, the results obtained under UHV cannot be extrapolated to nanoparticles in ambient atmosphere or dispersed in liquids.After an analysis of the stakes and challenges in the surface characterization of nanoparticles and a very brief overview of the usual techniques for surface studies, this paper presents the performance of Fourier transform infrared (FTIR) spectroscopy to investigate surface chemical composition, surface reactivity and surface functionalization of nanoparticles. As illustrating examples, the results of the FTIR surface analysis of different kinds of ceramic nanoparticles are discussed with regard to several fields of applications.

Water-based Si3N4 suspensions: Part I. Effect of processing routes on the surface chemistry and particle interactions

2000 ◽  
Vol 15 (1) ◽  
pp. 155-163 ◽  
Author(s):  
C. Galassi ◽  
F. Bertoni ◽  
S. Ardizzone ◽  
C. L. Bianchi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Particle Surface ◽  
Great Influence ◽  
Particle Interactions ◽  
Mixing Process ◽  
Mixing Processes ◽  
X Ray ◽  
Solid Liquid ◽  
Nitride Particle

Si3N4 powders manufactured by two different preparative routes were characterized for the solid–liquid interfacial reactivity and surface composition. Three mixing processes were tried to investigate the modifications of silicon nitride particle surface in aqueous suspensions. The surfaces of the starting powders and the dried mixed powders were investigated by x-ray photoelectron spectroscopy to determine the nature and ratios of surface groups. Electroacoustic measurements show that no change occurs in the isoelectric point for the mixed Si3N4 powders while the milling/mixing process has a great influence on the zeta potential magnitude and particle size distribution.

Structure-property Characterisation at Nanoscale using In-situ TEM and SEM

2016 ◽  
Vol 66 (4) ◽  
pp. 381 ◽  
Author(s):  
Rajdeep Sarkar ◽  
Chandan Mondal ◽  
Deepak Kumar ◽  
Sabyasachi Saha ◽  
Atul Kumar ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Atmospheric Pressure ◽  
Surface Composition ◽  
High Vacuum ◽  
Vacuum Condition ◽  
Ex Situ ◽  
Dissolution Behavior ◽  
High Vacuum Condition

<p>In-situ electron microscopy is an emerging technique for real time visualisation of micro-structural changes of a specimen under some applied constraints inside microscope. In this study, in-situ nanoindentation experimentation on a carbon nanocoil inside transmission electron microscope has been reported. The elastic modulus of the carbon nanocoil is found to be 177 GPa. Similar experiments are also carried out on carbon nanotubes, but force response of carbon nanotubes is beyond the limit of sensors presently available. The present study also reports the in-situ dissolution behavior of the secondary phases of a 7xxx series aluminum alloy under high vacuum condition in scanning electron microscope (SEM) in the temperature range of 350 °C to 400 °C. We report for the first time using in-situ SEM technique that dissolution of the MgZn2-base phase present as eutectic and divorced eutectic forms could start at a temperature as low as 300 °C, although the usual homogenisation temperature of such alloys is always &gt; 450 °C. Furthermore, the kinetics of dissolution of such phases, particularly when present in fine eutectic phase mixture, is significantly faster than what is observed under atmospheric pressure. It has been found that modification of surface composition under high vacuum condition plays a key role in the low temperature dissolution processes. It has further been found that the dissolution process does not start with the thinning of the IDC phase as proposed for Al-Zn-Mg-Cu alloys, rather it occurs by a combination of ‘spheroidisation’ and thinning process called ‘the thinning, discontinuation, and full dissolution’ (TDFD) mechanism. Results of the in-stu experiments under high vacuum are compared with the ex-situ dissolution experiments under normal atmospheric pressure.</p>

Nanowire Reconstruction on the 4H-SiC(1102) Surface

2007 ◽  
Vol 556-557 ◽  
pp. 529-532 ◽  
Author(s):  
M. Hetzel ◽  
Charíya Virojanadara ◽  
Wolfgang J. Choyke ◽  
Ulrich Starke
Keyword(s):  
Electron Spectroscopy ◽  
Auger Electron ◽  
Surface Composition ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Intrinsic Structure ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

Ordered reconstruction phases on the 4H-SiC(1102) surface have been investigated using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES) and scanning tunneling microscopy (STM). After initial hydrogen etching, the samples were prepared by Si deposition and annealing in ultra-high vacuum (UHV). Two distinct reconstruction phases develop upon annealing, first with a (2×1), and at higher temperatures with a c(2×2) LEED pattern. After further annealing the fractional order LEED spots vanish and a (1x1) pattern develops. For the (2×1) phase, STM micrographs show that adatom chains develop on large flat terraces, which in view of AES consist of additional Si. These highly linear and equidistant chains represent a self-assembled well-ordered pattern of nanowires developing due to the intrinsic structure of the 4H-SiC(1102) surface. For the c(2×2) phase AES indicates a surface composition close to the bulk stoichiometry. For the (1×1) phase a further Si depletion is observed.

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