Nanohole Coat/Fill with Pt via Chemical Deposition in Supercritical Fluids

2014 ◽  
Vol 617 ◽  
pp. 184-186
Author(s):  
Eiichi Kondoh ◽  
Toshiaki Goto ◽  
Mitsuhiro Watanabe
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluid ◽  
Supercritical Fluids ◽  
Incubation Time ◽  
Seed Layer ◽  
Noble Metals ◽  
Hydrogen Reduction ◽  
Chemical Deposition ◽  
Nanostructure Formation

This paper demonstrates nanostructure formation performed by supercritical fluid chemical deposition. Pt was deposited through hydrogen reduction of a Pt chelate being dissolved in supercritical carbon dioxide. Pt was deposited conformally inside nanotrences, however Pt did not grow thick due to a very long incubation time for the nucleation. Interestingly, SFCD Pt grew thick on already-existing noble metals. A two-step SFCD process was employed, where a Pt seed layer was deposited first and Pt was grown thicker in the subsequent run. This enabled to fill Pt in nanotrenches and nanoholes.

Generation and Propagation of Thermally Induced Acoustic Waves in Supercritical Fluids: Numerical and Experimental Results

2010 ◽  
Author(s):  
Bakhtier Farouk ◽  
Zhieheng Lei
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluid ◽  
Supercritical Fluids ◽  
Acoustic Waves ◽  
Rapid Heating ◽  
Time Dependent ◽  
Cylindrical Chamber ◽  
Thermally Induced ◽  
Supercritical Carbon

The behavior of thermally induced acoustic waves generated by the rapid heating of a bounding solid wall in a closed cylindrical chamber filled with supercritical carbon dioxide is investigated numerically and experimentally. A time-dependent one-dimensional problem is considered for the numerical simulations where the supercritical fluid is contained between two parallel plates. The NIST Reference Database 12 is used to obtain the property relations for supercritical carbon dioxide. The thermally induced pressure (acoustic) waves undergo repeated reflections at the two confining walls and gradually dissipate. The numerically predicted temperature of the bulk supercritical fluid is found to increase homogeneously (the so called piston effect) within the domain. The details of generation, propagation and dissipation of thermally induced acoustic waves in supercritical fluids are presented under different heating rates. In the experiments, a resistance-capacitance circuit is used to generate a rapid temperature increase in a thin metal foil located at one end of a closed cylindrical chamber. The time-dependent pressure variation in the chamber and the temperature history at the foil are recorded by a fast response measurement system. Both the experimental and numerical studies predict similar pressure wave shapes and profiles due to rapid heating of a wall.

Dynamic solubility measurement of substances in supercritical fluids

2019 ◽  
Vol 60 (12) ◽  
pp. 96-103
Author(s):  
Lenar Yu. Yarullin ◽  
◽  
Farizan R. Gabitov ◽  
Insaf I. Zamaliev ◽  
Lyudmila Y. Sabirova ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Phase Equilibria ◽  
Supercritical Fluid ◽  
Supercritical Fluids ◽  
Raw Materials ◽  
Plant Materials ◽  
Fluid Media ◽  
Tea Leaf ◽  
Supercritical Carbon

The study of currently known methods and devices for processing plant materials has shown that during the study period, the greatest interest (about 31%) of patent holders is manifested in increasing the yield of extractive substances. If we take as an example a tea leaf, then indeed, the formation of conditions for a more complete release of the target components into the aqueous phase during brewing can provide a more profitable and economical consumption of tea raw materials. The study of the thermodynamic principles of the use of supercritical fluid media and carbon dioxide, in particular, in the processing of plant materials and the processing of tea raw materials, as well as the development of methods for intensifying mass transfer to the aqueous phase when “brewing” tea leaves, are uniquely relevant tasks. An important section of thermodynamics is the concept of phase equilibria in systems of different composition. And one of the key characteristics of phase equilibria is such a thing as the solubility of a substance, including in supercritical fluid media. Since solutions of substances in supercritical fluids are diluted, the dependence of the solubility of substances on temperature, pressure, and density of a pure solvent near its critical point is of practical interest. The results of experimental studies of measuring the solubility of tannin in supercritical carbon dioxide by the dynamic method at a temperature of 308 and 333 K, in the pressure range from 8 to 26 MPa, are presented. The data obtained, firstly, indicate a low solubility of tannin in supercritical carbon dioxide, which is a positive moment for the implementation of the tea leaf pretreatment process in order to improve its biological potential, and secondly, a clear suppression of isolines is observed, which in turn indicates the presence of crossover behavior on solubility isotherms. Based on the results of the obtained experimental data on the solubility of tannin in supercritical carbon dioxide, a mathematical description of the solubility of tannin was carried out by the Peng-Robinson equation of state.

The Influence of Temperature and Concentration on Copper Deposition Kinetics in Supercritical Carbon Dioxide

2004 ◽  
Vol 812 ◽  
Author(s):  
Yinfeng Zong ◽  
James J. Watkins
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluids ◽  
Zero Order ◽  
Copper Deposition ◽  
Deposition Kinetics ◽  
Zero Order Kinetics ◽  
Concentration Interval ◽  
Kinetics Of ◽  
Supercritical Carbon

AbstractThe kinetics of copper deposition by the hydrogen-assisted reduction of bis(2,2,7- trimethyloctane-3,5-dionato)copper in supercritical carbon dioxide was studied as a function of temperature and precursor concentration. The growth rate was found to be as high as 31.5 nm/min. Experiments between 220 °C and 270 °C indicated an apparent activation energy of 51.9 kJ/mol. The deposition kinetics were zero order with respect to precursor at 250 °C and 134 bar and precursor concentrations between 0.016 and 0.38 wt.% in CO2. Zero order kinetics over this large concentration interval likely contributes to the exceptional step coverage obtained from Cu depositions from supercritical fluids.

scholarly journals SPATIAL NONUNIFORM DISTRIBUTION OF 235U ISOTOPE AT SUPERCRITICAL FLUID EXTRACTION WITH CARBON DIOXIDE IN A GRADIENT TEMPERATURE FIELD

2021 ◽  
pp. 98-103
Author(s):  
B.V. Borts ◽  
S.F. Skoromnaya ◽  
Yu. G. Kazarinov ◽  
I.M. Neklyudov ◽  
V.I. Tkachenko
Keyword(s):  
Carbon Dioxide ◽  
Temperature Field ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluid ◽  
Separation Factor ◽  
Natural Uranium ◽  
Nonuniform Distribution ◽  
Spatial Redistribution ◽  
Granite Samples ◽  
Supercritical Carbon

The spatial redistribution of the 235U isotope of natural uranium in a gradient temperature field along the height of the reactor in supercritical carbon dioxide has been experimentally investigated. The scheme of the reactor is given and the principle of operation of the reactor is described. The method of preparation of initial samples from granite samples containing natural uranium and the procedure of extraction are described. The conclusion about the spatial redistribution of 235U isotopes in supercritical carbon dioxide is based on the analysis of gamma spectra of extracts. It is shown that the concentration of the 235U isotope in a supercritical fluid is maximal near the lower heated flange of the reactor, and decreases with approaching the upper, cooled flange. It was concluded that the separation factor of the 235U isotope in supercritical carbon dioxide can be about 1.2 ± 0.12.

Design Principles of Surfactants for Polymerization in Supercritical CO2

2016 ◽  
Vol 852 ◽  
pp. 766-769
Author(s):  
Shi Ping Zhan ◽  
Qing Chun Qi ◽  
Qi Cheng Zhao ◽  
Shu Hua Chen ◽  
Wei Min Hou ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluids ◽  
Design Principle ◽  
Design Principles ◽  
Supercritical Carbon

In recent years, supercritical carbon dioxide, as a green chemical solvent, is widely used. The surfactants for polymerization in supercritical fluids have become one of the important issues. This paper mainly discusses the mechanism and influence of the surfactants in supercritical carbon dioxide system. The choice and design principle of surfactants and the recent development of surfactants were introduced in detail.

Nucleation of Tungsten on Titanium Nitride with Hydrogen Reduction of Tungsten Hexafluoride

1992 ◽  
Vol 282 ◽  
Author(s):  
D. Srinivas ◽  
R. Foster ◽  
S. Marcus ◽  
R. Arora ◽  
H. Rebenne
Keyword(s):  
Titanium Nitride ◽  
Nucleation Rate ◽  
Incubation Time ◽  
Seed Layer ◽  
Total Pressure ◽  
Hydrogen Reduction ◽  
Reduction Process ◽  
Tungsten Hexafluoride ◽  
Short Incubation Time ◽  
Competing Reactions

ABSTRACTIn this work, a hydrogen (H2) reduction process has been developed which gives tungsten (W) nucleation on titanium nitride (TiN) adhesion layers with a very short incubation time, eliminating the need for a silane (SiH4reduced seed layer. The nucleation was found to be strongly dependent on the following factors: temperature of the substrate, total pressure in chamber, and gas introduction sequence into the reactor. Theenhanced nucleation rate has been explained based on two competing reactions: dissociation of H2, and formation of titanium subfluorides on the TiN surface.

scholarly journals Creation of interfaces in composite/hybrid nanostructured materials using supercritical fluids

2015 ◽  
Vol 4 (6) ◽  
Author(s):  
Oana Pascu ◽  
Samuel Marre ◽  
Cyril Aymonier
Keyword(s):  
Surface Chemistry ◽  
Size Distribution ◽  
Nanostructured Materials ◽  
Supercritical Fluid ◽  
Supercritical Fluids ◽  
Chemical Deposition ◽  
Good Control ◽  
Present Review ◽  
Batch Mode ◽  
Distribution Composition

AbstractBy structuring matter at the nano level using highly versatile nanotechnology approaches and apparatus, multifunctionalities with manifestation of enhanced and/or novel useful properties could be attained. The challenges in nanoengineering are the ability to tune the nano-object characteristics (size, distribution, composition, and surface chemistry) and to have a good control on the possible synergy created at the interfaces, especially in the case of complex multifunctional materials. Surface nanoengineering goes hand in hand with the creation of interfaces between nano-objects – either inorganic or hybrid ones – and a closer look in this direction is essential. The present review aims at presenting the possibilities of surface nanoengineering by versatile approaches, namely supercritical fluids processes. Two main routes of nanostructuration, each containing three concepts, will be discussed: supercritical fluid chemical deposition performed in batch mode and continuous supercritical fluid synthesis. Both approaches can be used to access interesting materials with desired properties, with the choice of process depending on what the readers are pursuing.

Supercritical argon as a mobile phase for the flame photometric detection of sulfur

2003 ◽  
Vol 81 (10) ◽  
pp. 1051-1056 ◽  
Author(s):  
Kevin B Thurbide ◽  
Brad W Cooke
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Fluid ◽  
Supercritical Fluid Chromatography ◽  
Mobile Phase ◽  
Packed Column ◽  
Flow Rates ◽  
Photometric Detection ◽  
Flame Photometric Detection ◽  
Background Emission

The background emission properties of supercritical argon and supercritical carbon dioxide mobile phases in packed column supercritical fluid chromatography (pSFC) with flame photometric detection (FPD) were compared. As column flow rates were increased toward common values used in pSFC, the carbon dioxide background emission grew enormously. The resulting emission spectrum displayed dominant features at wavelengths between 325 and 525 nm, consisting of a complex series of overlapping molecular emission band systems partly attributed to CO* and CH*. By comparison, when using the same flow rates with a supercritical argon mobile phase, the background emission was identical to that of the FPD flame without column effluent. In terms of intensity, when using a column flow rate of 2 mL/min, supercritical carbon dioxide contributes a background emission in the FPD that is about 3 × 105 times larger than that produced by supercritical argon. This difference leads to an improvement of two orders of magnitude in the pSFC-FPD signal-to-noise ratio for sulfur when a supercritical argon mobile phase is used. Results indicate that supercritical argon could also be advantageous for the pSFC-FPD analysis of other elements.Key words: supercritical fluid chromatography, packed column, flame photometric detection, supercritical argon.

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