scholarly journals Dealloying of Cu-Mg-Ca Alloys

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 919 ◽  
Author(s):  
Wael Ben Mbarek ◽  
Eloi Pineda ◽  
Lluïsa Escoda ◽  
Joan Suñol ◽  
Mohamed Khitouni
Keyword(s):  
Alloy Composition ◽  
Pure Water ◽  
Nanoporous Structure ◽  
H2so4 Solution ◽  
Ideal Candidate ◽  
Nanoporous Copper ◽  
Alloy State ◽  
Quenching Process ◽  
Precursor Alloy ◽  
Fast Dissolution

The chemical dealloying of Cu-Mg-Ca alloys in free corrosion conditions was investigated for different alloy compositions and different leaching solutions. For some of the precursor alloys, a continuous, pure fcc copper with nanoporous structure can be obtained by dealloying in 0.04 M H2SO4 solution. Superficial nanoporous copper structures with extremely fine porous size were also obtained by dealloying in pure water and 0.1 M NaOH solutions. The dealloying of both amorphous and partially crystalline alloys was investigated obtaining bi-phase nanoporous/crystal composites with microstructures depending on the precursor alloy state. The fast dissolution of Mg and Ca makes the Cu-Mg-Ca system an ideal candidate for obtaining nanoporous copper structures with different properties as a function of different factors such as the alloy composition, the quenching process, and leaching conditions.

Surface Modification for Polystyrene Colloidal Particles with Controlled Charge Densities

2007 ◽  
Vol 7 (11) ◽  
pp. 3995-3999
Author(s):  
Jongman Lee ◽  
Oh-Sun Kwon ◽  
Kwanwoo Shin ◽  
Ju-Myung Song ◽  
Joon-Seop Kim ◽  
...  
Keyword(s):  
Surface Modification ◽  
Acrylic Acid ◽  
Surface Charge Density ◽  
Colloidal Particles ◽  
Mixed Solvent ◽  
Pure Water ◽  
Random Copolymer ◽  
Aqueous Dispersions ◽  
Charge Densities ◽  
Quenching Process

A significant amount of polystyrene sulfonated acid (PSSA) and poly(styrene-ran-acrylic acid) (PSAA) random copolymer can be adsorbed by dispersion of PS particles via a swelling-quenching process. A THF-water mixed solvent was used in the swelling process and a large amount of pure water was used, to give a low concentration of THF% in quenching process. Our results showed that functional PSSA groups were randomly and tightly adsorbed to the PS particles. When the mol.% of charged segments was increased, the progressive adsorption of PSSA chains to the PS particles leads to an increase in the electrophoretic mobility and zeta-potential of aqueous dispersions. Thus, we were able to obtain well-distributed surface charge density on the PS particles.

scholarly journals Формирование нанопористых пленок силицидов меди

2019 ◽  
Vol 53 (3) ◽  
pp. 418
Author(s):  
Э.Ю. Бучин ◽  
В.В. Наумов ◽  
С.В. Васильев
Keyword(s):  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Three Dimensional ◽  
Nanoporous Structure ◽  
Copper Silicide ◽  
Phase Synthesis ◽  
Cu Content ◽  
Inorganic Acids ◽  
Nanoporous Copper ◽  
Kirkendall Voids

AbstractThe possibility of forming nanoporous copper-silicide films with different phase compositions is experimentally demonstrated. For this purpose, the parameters of the initial a -Si/Cu structure and the conditions of its annealing are chosen so that the process of solid-phase synthesis comes to a halt at the stage of formation of a branched silicide cluster. Then the films are subjected to liquid etching in a mixture of diluted inorganic acids. In this case, the metastable Cu_ x Si phase with a low Cu content is selectively removed, and a three-dimensional silicide cluster is released. At the same time, surface Kirkendall voids present in the films open. As a result of these two processes in combination, a nanoporous structure is formed.

Influence of alloy composition on nanoporous structure by dealloying Mn-Cu ribbons

Rare Metals ◽  
2011 ◽  
Vol 30 (S1) ◽  
pp. 370-374 ◽  
Author(s):  
Jiwei Zheng ◽  
Shichao Zhang ◽  
Wenbo Liu ◽  
Yalan Xing
Keyword(s):  
Alloy Composition ◽  
Nanoporous Structure

A Preparation Method of Patterned Nanoporous Copper

2013 ◽  
Vol 663 ◽  
pp. 322-325 ◽  
Author(s):  
Heng Yue ◽  
Cong Chun Zhang ◽  
Zhuo Qing Yang ◽  
Hong Wang ◽  
Gui Fu Ding ◽  
...  
Keyword(s):  
Thin Film ◽  
Preparation Method ◽  
Alloy Thin Film ◽  
Fabrication Technique ◽  
Micro Fabrication ◽  
Electro Deposition ◽  
Nanoporous Copper ◽  
Plating Solution ◽  
Alloy Plating ◽  
Precursor Alloy

Graphic nanoporous copper (NPC) was prepared by a new method. Cu68Zn32 and Cu36Zn64 (atomic percentages) precursor alloy thin film was deposited by electro-deposition in acidic alloy plating solution and then dealloyed in hydrochloric acid to fabricate nanoporous copper (NPC) with pore size from 30nm to 100nm. The results show that the microstructure of NPC can be controlled by changing alloy plating solution and dealloying process, this process also maintains compatibility with micro-fabrication technique.

scholarly journals Experimental Study on Quenching of a Small Metal Sphere in Nanofluids

2008 ◽  
Author(s):  
H. Kim ◽  
J. Buongiorno ◽  
L. W. Hu ◽  
T. McKrell ◽  
G. DeWitt
Keyword(s):  
Pure Water ◽  
Nucleate Boiling ◽  
Deionized Water ◽  
Vapor Film ◽  
Sphere Surface ◽  
Steel Sphere ◽  
Quenching Process ◽  
Higher Temperature ◽  
Low Volume ◽  
Subsequent Quenching

The objective of this research is to systematically investigate the quenching characteristics of a hot sphere in nanofluids. The experiments are carried out with a small (9.5 mm) stainless steel sphere with initial temperatures near 1000 °C. Alumina nanofluids and deionized water are tested at low volume concentrations (less than 0.1% by volume) and saturated conditions (100 °C). The results show that the quenching behavior in nanofluids is nearly identical to that in pure water. Moreover it is found that some nanoparticles accumulate on the sphere surface during the quenching process. Such accumulation of nanoparticles on the surface promotes the destabilization of the vapor film in subsequent quenching experiments, thus accelerating the return to nucleate boiling at higher temperature than that in the clean surface case.

scholarly journals Design and Preparation of Nanoporous Cu/Ag Multilayer Films

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1187
Author(s):  
Yufei Wang ◽  
Shuangle Zhang ◽  
Zefeng Wu ◽  
Yong Fan ◽  
Huaqiang Chen ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Composite Films ◽  
Single Layer ◽  
Multilayer Films ◽  
Nanoporous Structure ◽  
Multilayer Composite ◽  
H2so4 Solution ◽  
Nanoporous Films ◽  
Layer Structures ◽  
Morphology And Structure

Cu30Al70 and Ag30Al70 multilayer precursor films were prepared by magnetron sputtering, respectively. Then the nanoporous Cu/Ag multilayer composite films were successfully prepared by selecting the appropriate H2SO4 solution as the dealloying solution. It was found that the nanoporous structure was stable in the dealloying solution. The morphology and structure of nanoporous films are mainly related to the phase composition of precursors. The structure of nanoporous multilayers can be simply regarded as the superposition of single-layer structures. Our work shows that nanoporous multilayers can be well-prepared by magnetron sputtering combined with dealloying.

Nanoporous Copper Fabricated by Dealloying Mn–Cu Precursors with Minor Nickel Element Addition and Heat Treatment Coarsening

NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850058 ◽  
Author(s):  
Jinyi Wang ◽  
Sen Yang
Keyword(s):  
Heat Treatment ◽  
Pore Size ◽  
Three Dimensional ◽  
Nanoporous Structure ◽  
Surface Diffusivity ◽  
Nanoporous Copper ◽  
Element Addition ◽  
Microscopic Morphology ◽  
Morphology Characterization ◽  
Scanning Electron

Nanoporous copper (NPC) and nanoporous copper-nickel (NPC-Ni) can be prepared by free corrosion dealloying Mn[Formula: see text]Cu[Formula: see text]Nix ([Formula: see text], 1, 3[Formula: see text]at.% Ni) precursor alloys. Microscopic morphology characterization by scanning electron microscopy exhibited a three-dimensional bicontinuous porous structure with nanoscale ligaments and pores. NPC with a pore size of 48.7[Formula: see text]nm was obtained in 0.1[Formula: see text]M hydrochloric acid solution for 3.5[Formula: see text]h dealloyed at 25[Formula: see text]C. Under the same free corrosion dealloying condition, NPC-Ni1 and NPC-Ni3 were obtained with the pore size of 36.6[Formula: see text]nm and 28.1[Formula: see text]nm, respectively. The results indicate that minor Ni atoms addition to the precursor greatly refined the dealloyed nanoporous structure. This effect could be attributed to the lower Ni surface diffusivity than that of Cu and resulted in slow down of the diffusion and rearrangement of Cu atoms during dealloying process. Post-dealloying heat treatment at 300[Formula: see text]C, 450[Formula: see text]C and 600[Formula: see text]C made the ligaments coarsen in NPC and NPC-Ni.

scholarly journals Effect of Dealloying Time and Post-Annealing on the Surface Morphology and Electrocatalytic Behavior of Nanoporous Copper Films for CO2 Reduction Reaction

2021 ◽  
Author(s):  
Wang-You Zeng ◽  
Jia-Hao Lai ◽  
I-Chung Cheng
Keyword(s):  
Surface Morphology ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Co2 Reduction ◽  
Annealing Treatment ◽  
Reduction Reaction ◽  
Nanoporous Structure ◽  
Post Annealing ◽  
Nanoporous Copper ◽  
Ligament Size

Abstract Electrocatalytic reduction reaction of CO2 (CO2RR) is one of the promising routes to mitigate global warming via transforming greenhouse gas into valuable chemical feedstocks. By adding proper electrocatalysts, such as nanoporous copper (NPC) with an average ligament size of 37 ± 6 nm, hydrocarbons could be produced at a relatively low overpotential. As the dealloying time increased to 156 hrs, the NPC was transformed into CuO nanosheet structure, which yielded larger electrochemical surface area (ECSA) and current density than the as-prepared NPC films. However, the Faraday efficiency (FE) of the major conversion product, formic acid (HCOOH), decreased from 29 to 8% when the nanosheet structure was used as electrocatalyst. On the other hand, the surface morphology of the NPC films remained similar while the average ligament size increased from 37 to 63 nm after a post-annealing treatment at 500 °C for 4 hrs. Both the current density and ECSA of this post-annealed NPC film were nearly 3 times higher than those of as-prepared NPC film, and the FE toward HCOOH increased from 29 to 45%. X-ray photoelectron spectroscopy and Raman spectroscopy revealed that Cu2O were present on the nanoporous structure, which enhanced the selectivity and FE toward HCOOH in CO2RR.

EFFECTIVE NANOPOROUS COPPER FOR ELECTROCATALYTIC REDUCTION OF CARBON DIOXIDE IN IONIC LIQUID

2010 ◽  
Vol 03 (03) ◽  
pp. 181-183 ◽  
Author(s):  
XUAN YUN WANG ◽  
SU QIN LIU ◽  
KE LONG HUANG ◽  
QIU JU FENG ◽  
BIN LIU ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ionic Liquid ◽  
High Surface ◽  
High Surface Area ◽  
Copper Film ◽  
Nanoporous Structure ◽  
Cyclic Voltammogram ◽  
Electrocatalytic Reduction ◽  
Nanoporous Copper ◽  
Catalysis Efficiency

Nanoporous copper as a robust and efficient electrocatalyst for the electrocatalytic reduction of CO2 in ionic liquid has been successfully developed due to its advantages of high surface area, open porosity and high catalysis efficiency. Nanoporous copper film was prepared by a simple dealloying method and can be directly fabricated on the surface of the electrode. The electrochemical property for electrocatalytic reduction of CO2 in ionic liquid was investigated by cyclic voltammogram (CV), showing enhanced electrocatalytic activity due to its nanoporous structure.

Nanoporous Copper Dealloyed from a Nanocrystallized Ticu Alloy

2013 ◽  
Vol 750 ◽  
pp. 72-75 ◽  
Author(s):  
Zhen Hua Dan ◽  
Feng Xiang Qin ◽  
Yu Sugawara ◽  
Izumi Muto ◽  
Nobuyoshi Hara
Keyword(s):  
Heat Treatment ◽  
Phase Separation ◽  
Pore Size ◽  
Intermetallic Phases ◽  
Nanoporous Structure ◽  
Selective Area ◽  
Nanoporous Copper ◽  
Immersion Condition ◽  
The Difference ◽  
Xrd Patterns

Nanoporous copper (NPC) was fabricated through dealloying nanocrystallized TiSubscript text50Cu50 ribbon alloy under a free immersion condition in HF solutioSubscript textns at 25 °C. Multimodal nanoporous structure was formed due to the presence of Ti3Cu4 phase, which was co-precipitated with Ti2Cu during the heat treatment at T = 400 °C (Italic textTSubscript textg Italic textT Subscript textx). The presence of multiphases in tItalic texthe starting material caused the different behavior in the evolution of nanoporosity. In 0.03 mol/L HF solution, the bimodal nanoporous copper with a pore size of 54 nm and 184 nm was obtained in different regions where the composition differed. The ligament scale lengths in two regions were confirmed to be 54 nm and 203 nm, respectively. In 0.13 mol/L HF solution, the difference in the pore size and phase separation became weak, accompanying with the evolution of larger pores and smaller ligaments. The residue after dealloying was confirmed to be fcc Cu, indicated by the presence of Cu (111), (200), (220) and (311) in XRD patterns and TEM selective area diffraction pattern. The microstructure of the starting materials for dealloying, such as intermetallic phases, played a key role in the formation of the final multimodal nanoporous structure.

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