Mechanical and physical characterization of copper foam

El-Hadek, Medhat A.; Kaytbay, Saleh

doi:10.1007/s10999-008-9058-2

Cited by 57 publications

(33 citation statements)

References 12 publications

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“…[4] Aluminum has dominated the metal foam industry due to its low melting temperature and relative stability in air. [3,[6][7][8][9][10][11] The solid state foaming of metals by gas entrapment [12,13] typically uses a two-step process: (i) entrap gas within the interparticle voids during powder consolidation and (ii) heat to expand the entrapped gas such that the internal pressure exceeds the yield strength and enables plasticity or creep to increase porosity. [3,[6][7][8][9][10][11] The solid state foaming of metals by gas entrapment [12,13] typically uses a two-step process: (i) entrap gas within the interparticle voids during powder consolidation and (ii) heat to expand the entrapped gas such that the internal pressure exceeds the yield strength and enables plasticity or creep to increase porosity.…”

mentioning

confidence: 99%

Towards Reaching the Theoretical Limit of Porosity in Solid State Metal Foams: Intraparticle Expansion as A Primary and Additive Means to Create Porosity

2014

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Metallic foams and porous metal structures are valuable for their unique characteristics such as high specific strength, energy absorption at constant crushing load, efficient heat transfer and acoustic properties, all of which can be tailored by controlling the porosity. [1][2][3] Many techniques for generating metal foams exist, but the vast majority of metal foam production is through liquid state processes such as the melt processing of aluminum by gas injection or decomposition of a dispersed foaming agent. [4] Aluminum has dominated the metal foam industry due to its low melting temperature and relative stability in air. [5] Reactive metals and those with higher melting temperatures require special processing, usually through solid state techniques. [3,[6][7][8][9][10][11] The solid state foaming of metals by gas entrapment [12,13] typically uses a two-step process: (i) entrap gas within the interparticle voids during powder consolidation and (ii) heat to expand the entrapped gas such that the internal pressure exceeds the yield strength and enables plasticity or creep to increase porosity. [14] While some powder metallurgy (PM) processes can exceed 85% porosity (e.g. using a polymer foam as a fugitive template [7] ), it is more common for PM processes to produce porosity levels between 20 and 40%. [5,14] In fact, Elzey and Wadley [14] calculated that the limit of the solid state foaming process by gas entrapment is %65% porosity, even under ideal, superplastic conditions. Experimentally, this method has produced foams with porosity only as high as 53%, [15] but porosity has typically been limited to %40%. These relatively low porosity levels (compared to liquid state processes) constrain the applications of metal foams produced via solid state foaming. To extend the capabilities of solid state foaming, we have developed an additive means of creating porosity by intraparticle expansion.The current limitation of solid-state expansion by gas entrapment is dictated by voids formed between solid particles during consolidation. In this model, the initial gas pressure and foaming temperature determine the resulting porosity. However, if the expanding gas is not limited to just that which is trapped between particles, but is also located within particles, solid state foaming may assume a character more akin to expandable polymers which foam from the constituent pellets. This concept is a paradigm shift in terms of the solid state foaming process and the achievable levels of porosity. On the basis of this simple, powder feedstock expansion, there is universal application to powder metallurgy methods for foaming. In this work, we examine the microstructure and morphology of a Cu-Sb alloy that expands to porosities of close to 40% within individual particles, resulting in absolute porosity of 69% in sintered samples.The Cu-Sb alloy powder was formed by mechanically alloying Cu and Sb (Alfa Aesar, 99.9 and 99.5%, respectively) at cryogenic temperature (À196°C) for 4 h using a modified SPEX 8000M Mixer/Mill. The elemen...

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Towards Reaching the Theoretical Limit of Porosity in Solid State Metal Foams: Intraparticle Expansion as A Primary and Additive Means to Create Porosity

2014

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“…During powder processing with space holder particles, porosity can be introduced by adding an additional phase (space holder particles) to the metal powder to retain spaces in the material, which can be removed afterwards by chemical or thermal (during sintering) means [17,18,19,20,21]. The shape of the space holder particles controls the pore morphology of the pore structure.…”

Section: Introductionmentioning

confidence: 99%

Application of Aluminium Flakes in Fabrication of Open-Cell Aluminium Foams by Space Holder Method

et al. 2018

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In the current study, a first attempt at using aluminum flakes for the manufacture of open-cell aluminum foams with the space holder method is presented. The method involves powder mixing, compaction, leaching, and sintering processes. Saccharose particles were used as space holders, and multiple parameters were investigated to optimize the manufacturing processing route in order to produce high-quality open-cell aluminum foams with a simple, economic, and environmentally friendly method. The implementation of aluminum flakes leads to foams with 80 vol.% porosity, an excellent internal open-cell porous structure, low green compaction pressures, and does not require the use of binding additives.

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“…Current collectors are usually made from stainless steel, nickel, copper, carbon or aluminum foils. [27][28][29] Copper current collectors are also well known for their chemical compatibility with battery electrolytes and ability to improve the cycle performance of LIBs. The "atness" (in the context of this study this term indicates the lack of specic meso-and microscale protrusions on the surface of the electrode) of traditional current collectors reduces the contact area available for (1) electron transfer with and (2) adhesion of anode/cathode materials to the electrodes.…”

Section: Introductionmentioning

confidence: 99%

Low-current field-assisted assembly of copper nanoparticles for current collectors

et al. 2015

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Current collectors are essential features of batteries and many other electronic devices being responsible for efficient charge transport to active electrode materials. Three-dimensional (3D), high surface area current collectors considerably improve the performance of cathodes and anodes in batteries, but their technological implementation is impeded by the complexity of their preparation, which needs to be simple, fast, and energy efficient. Here we demonstrate that field-stimulated assembly of ∼3 nm copper nanoparticles (NPs) enables the preparation of porous Cu NP films. The use of NP dispersions enables 30× reduction of the deposition current for making functional 3D coatings. In addition to high surface area, lattice-to-lattice connectivity in the self-assembly of NPs in 3D structures enables fast charge transport. The mesoscale dimensions of out-of-plane features and the spacing between them in Cu films made by field-stimulated self-assembly of NPs provides promising morphology for current collection in lithium ion batteries (LIBs). Half-cell electrochemical models based on self-assembled films show improved specific capacity, total capacity, and cycling performance compared to traditional flat and other 3D current collectors. While integration of active electrode material into the 3D topography of the current collector needs to be improved, this study indicates that self-assembled NP films represent a viable manufacturing approach for 3D electrodes.

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Mechanical and physical characterization of copper foam

Cited by 57 publications

References 12 publications

Towards Reaching the Theoretical Limit of Porosity in Solid State Metal Foams: Intraparticle Expansion as A Primary and Additive Means to Create Porosity

Towards Reaching the Theoretical Limit of Porosity in Solid State Metal Foams: Intraparticle Expansion as A Primary and Additive Means to Create Porosity

Application of Aluminium Flakes in Fabrication of Open-Cell Aluminium Foams by Space Holder Method

Low-current field-assisted assembly of copper nanoparticles for current collectors

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