Combination of Universal Chemical Deposition and Unique Liquid Etching for the Design of Superhydrophobic Aramid Paper with Bioinspired Multiscale Hierarchical Dendritic Structure

Author(s):  
Jianbin Tang ◽  
Ruiqing Zou ◽  
Xin Zhang ◽  
Yun Zhong ◽  
Mengyao Li ◽  
...  
2003 ◽  
Vol 762 ◽  
Author(s):  
H. Águas ◽  
L. Pereira ◽  
A. Goullet ◽  
R. Silva ◽  
E. Fortunato ◽  
...  

AbstractIn this work we present results of a study performed on MIS diodes with the following structure: substrate (glass) / Cr (2000Å) / a-Si:H n+ (400Å) / a-Si:H i (5500Å) / oxide (0-40Å) / Au (100Å) to determine the influence of the oxide passivation layer grown by different techniques on the electrical performance of MIS devices. The results achieved show that the diodes with oxides grown using hydrogen peroxide present higher rectification factor (2×106)and signal to noise (S/N) ratio (1×107 at -1V) than the diodes with oxides obtained by the evaporation of SiO2, or by the chemical deposition of SiO2 by plasma of HMDSO (hexamethyldisiloxane), but in the case of deposited oxides, the breakdown voltage is higher, 30V instead of 3-10 V for grown oxides. The ideal oxide thickness, determined by spectroscopic ellipsometry, is dependent on the method used to grow the oxide layer and is in the range between 6 and 20 Å. The reason for this variation is related to the degree of compactation of the oxide produced, which is not relevant for applications of the diodes in the range of ± 1V, but is relevant when high breakdown voltages are required.


2020 ◽  
pp. 179-181
Author(s):  
A.A. Abrashov A.A. ◽  
E.G. Vinokurov ◽  
M.A. Egupova ◽  
V.D. Skopintsev

The technological (deposition rate, coating composition) and functional (surface roughness, microhardness) characteristics of chemical composite coatings Ni—Cu—P—Cr2O3 obtained from weakly acidic and slightly alkaline solutions are compared. It is shown that coatings deposited from slightly alkaline solution contain slightly less phosphorus and chromium oxide than coatings deposited from weakly acid solution (2...3 % wt. phosphorus and up to 3.4 % wt. chromium oxide), formed at higher rate (24...25 microns per 1 hour of deposition at temperature of 80 °C), are characte rized by lower roughness and increased microhardness. The Vickers microhardness at 0.05 N load of composite coatings obtained from slightly alkaline solution and heat-treated at 400 °C for 1 hour is 13.5...15.2 GPa, which is higher than values for coatings deposited made of weakly acidic solution. The maximum microhardness of coatings is achieved at concentration 20 g/l of Cr2O3 particles. The technology of chemical deposition of Ni—Cu—P—Cr2O3 coatings formed in slightly alkaline solution is promising for obtaining of materials with increased hardness and wear resistance.


Author(s):  
Д.Л. Байдаков

Методом химического нанесения из растворов халькогенидных стекол в н-бутиламине получены многокомпонентные халькогенидные пленки CuI-As2Se3, CuI-PbI2-As2Se3, CuI-SbI3-As2Se3, CuI-SbI3-PbI2-As2Se3. Синтез многокомпонентных медьсодержащих халькогенидных стекол, использовавшихся для нанесения пленок, проводили методом вакуумной плавки в кварцевых ампулах при температуре 400…950 °С и остаточном давлении не более 0,13 Па. Закалку стекол производили от 600 °С в воду со льдом с разливом расплава в ампуле. Навеску стекла размельчали в порошок и кипятили в н-бутиламине до полного растворения. Для предотвращения процессов окисления, нанесение и отжиг пленок проводили в атмосфере химически инертного азота. Подложку помещали на устройство для вращения, наносили на нее раствор и вращали подложку со скоростью несколько тысяч оборотов в минуту. Отжиг пленок проводили при температуре 100 °С в течение 1 ч. Измерение электропроводности полученных пленок проводили на постоянном и переменном токе в зависимости от значений электропроводности в температурном интервале 20…100 °С. Измерение коэффициентов диффузии проводили абсорбционным методом. Из диффузионных экспериментов определены значения коэффициентов диффузии катионов изотопа 110mAg в медьсодержащих халькогенидных пленках. Установлено, что значения коэффициентов диффузии ионов Ag+ в химически нанесенных пленках и исходных стеклах практически не различаются. Аналогию значений коэффициентов диффузии изотопа 110mAg в халькогенидных стеклах и пленках на их основе можно объяснить сохранением полимерной сетки связей халькогенидных стекол при их растворении в органических основаниях (аминах). В процессе нанесения и формирования пленок полимерная (макромолекулярная) структура раствора халькогенидных стекол сохраняется. The method of chemical deposition from solutions of chalcogenide glasses in n-butyl amine obtained multicomponent chalcogenide films CuI-As2Se3, CuI-PbI2-As2Se3, CuI-SbI3-As2Se3, CuI-SbI3-PbI2-As2Se3. Synthesis of copper multicomponent chalcogenide glasses, used for film deposition was carried out by vacuum melting in quartz ampoule at a temperature of 400…950 °C and a residual pressure of not more than 0.13 Pa. The temperature of glass produced from the 600 °C to the ice water spill of the melt in the ampoule. Weigh glass comminuted to a powder and heated in n-butylamine until complete dissolution. To prevent oxidation, deposition and annealing of the films was carried out in an atmosphere of nitrogen chemically inert. The substrate is placed on a device for rotating, it was applied to the solution and the substrate was rotated at a speed of several thousand revolutions per minute. Annealing of the films was carried out at 100 °C for 1 hour. Measurement of the electrical conductivity of the obtained films was conducted at a constant current and variable depending on the conductivity values ​​in the temperature range from 20 to 100 °C. Measurement of diffusion coefficients was performed according to the absorption method. From diffusion experiments, the values ​​of the diffusion coefficients 110mAg isotope cations in copper chalcogenide films. It was found that the values ​​of the diffusion coefficients of the ions Ag+ in a chemically deposited films and the original glasses are indistinguishable. The analogy of the diffusion coefficient values ​​110mAg isotope in chalcogenide glasses and films based on them can be attributed to the preservation of the polymer network connections chalcogenide glasses when dissolved in organic bases (amines). During application and film formation the polymer (macromolecular) structure of chalcogenide glasses of the solution is maintained.


2004 ◽  
Vol 126 (3) ◽  
pp. 619-626 ◽  
Author(s):  
Hakan Ertu¨rk ◽  
Ofodike A. Ezekoye ◽  
John R. Howell

The boundary condition design of a three-dimensional furnace that heats an object moving along a conveyor belt of an assembly line is considered. A furnace of this type can be used by the manufacturing industry for applications such as industrial baking, curing of paint, annealing or manufacturing through chemical deposition. The object that is to be heated moves along the furnace as it is heated following a specified temperature history. The spatial temperature distribution on the object is kept isothermal through the whole process. The temperature distribution of the heaters of the furnace should be changed as the object moves so that the specified temperature history can be satisfied. The design problem is transient where a series of inverse problems are solved. The process furnace considered is in the shape of a rectangular tunnel where the heaters are located on the top and the design object moves along the bottom. The inverse design approach is used for the solution, which is advantageous over a traditional trial-and-error solution where an iterative solution is required for every position as the object moves. The inverse formulation of the design problem is ill-posed and involves a set of Fredholm equations of the first kind. The use of advanced solvers that are able to regularize the resulting system is essential. These include the conjugate gradient method, the truncated singular value decomposition or Tikhonov regularization, rather than an ordinary solver, like Gauss-Seidel or Gauss elimination.


2005 ◽  
Vol 475-479 ◽  
pp. 655-660 ◽  
Author(s):  
Q. Feng ◽  
L.J. Rowland ◽  
T.M. Pollock

Three unusual Ru-rich phases have been identified in a multicomponent Ni-base single crystal superalloy, including a L21 Ru2AlTa Heusler phase, a B2 RuAl phase and a hcp Re(Ru)-rich δ phase. These phases have their own preferential precipitation location within the dendritic structure. No conventional topologically-close-packed (TCP) phases have been observed with thermal exposure at 950oC for 1500 hours.


2020 ◽  
Author(s):  
L. A. Brusnitsina ◽  
E. I. Stepanovskih ◽  
T. A. Alekseeva
Keyword(s):  

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110294
Author(s):  
Khaled Abd El-Aziz ◽  
Emad M Ahmed ◽  
Abdulaziz H Alghtani ◽  
Bassem F Felemban ◽  
Hafiz T Ali ◽  
...  

Aluminum alloys are the most essential part of all shaped castings manufactured, mainly in the automotive, food industry, and structural applications. There is little consensus as to the precise relationship between grain size after grain refinement and corrosion resistance; conflicting conclusions have been published showing that reduced grain size can decrease or increase corrosion resistance. The effect of Al–5Ti–1B grain refiner (GR alloy) with different percentages on the mechanical properties and corrosion behavior of Aluminum-magnesium-silicon alloy (Al–Mg–Si) was studied. The average grain size is determined according to the E112ASTM standard. The compressive test specimens were made as per ASTM: E8/E8M-16 standard to get their compressive properties. The bulk hardness using Vickers hardness testing machine at a load of 50 g. Electrochemical corrosion tests were carried out in 3.5 % NaCl solution using Autolab Potentiostat/Galvanostat (PGSTAT 30).The grain size of the Al–Mg–Si alloy was reduced from 82 to 46 µm by the addition of GR alloy. The morphology of α-Al dendrites changes from coarse dendritic structure to fine equiaxed grains due to the addition of GR alloy and segregation of Ti, which controls the growth of primary α-Al. In addition, the mechanical properties of the Al–Mg–Si alloy were improved by GR alloy addition. GR alloy addition to Al–Mg–Si alloy produced fine-grained structure and better hardness and compressive strength. The addition of GR alloy did not reveal any marked improvements in the corrosion properties of Al–Mg–Si alloy.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 408
Author(s):  
Ewa Sjöqvist Persson ◽  
Sofia Brorson ◽  
Alec Mitchell ◽  
Pär G. Jönsson

This study focuses on the impact of solidification on the inclusion morphologies in different sizes of production-scale electro-slag remelting (ESR) and electro-slag remelting under a protected pressure-controlled atmosphere, (PESR), ingots, in a common martensitic stainless steel grade. The investigation has been carried out to increase the knowledge of the solidification and change in inclusion morphologies during ESR and PESR remelting. In order to optimize process routes for different steel grades, it is important to define the advantages of different processes. A comparison is made between an electrode, ESR, and PESR ingots with different production-scale ingot sizes, from 400 mm square to 1050 mm in diameter. The electrode and two of the smallest ingots are from the same electrode charge. The samples are taken from both the electrode, ingots, and rolled/forged material. The solidification structure, dendrite arm spacing, chemical analyzes, and inclusion number on ingots and/or forged/rolled material are studied. The results show that the larger the ingot and the further towards the center of the ingot, the larger inclusions are found. As long as an ingot solidifies with a columnar dendritic structure (DS), the increase in inclusion number and size with ingot diameter is approximately linear. However, at the ingot size (1050 mm in diameter in this study) when the center of the ingot converts to solidification in the equiaxial mode (EQ), the increase in number and size of the inclusions is much higher. The transition between a dendritic and an equiaxial solidification in the center of the ingots in this steel grade takes place in the region between the ingot diameters of 800 and 1050 mm.


ACS Nano ◽  
2021 ◽  
Vol 15 (3) ◽  
pp. 4617-4626
Author(s):  
Jianmin Huang ◽  
Yu Pan ◽  
Tao Wang ◽  
Shengsheng Cui ◽  
Lin Feng ◽  
...  

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