X-ray studies of nanoporous gold: Powder diffraction by large crystals with small holes

Graf, Matthias; Ngô, Bao-Nam Dinh; Weißmüller, J.; Markmann, Jürgen

doi:10.1103/physrevmaterials.1.076003

Cited by 18 publications

(29 citation statements)

References 89 publications

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“…The Cu45 and Cu40 spectra show the fcc-Cu peaks (indicated in the figure) together with small intensity reflections at lower angles. The large broadness of the fcc-Cu peaks is expected in nanoporous structures [40] and it is dependent on various factors such as the ligament size, the porous fraction, the microstrain of the lattice and the size of the copper crystallites forming the ligaments [41]. The contribution of additional phases increases in Cu35 and Cu30 in agreement with the SEM images above.…”

Section: Dealloying Of Series 2 In 004 M H 2 Sosupporting

confidence: 82%

Dealloying of Cu-Mg-Ca Alloys

Mbarek

Pineda

Escoda

et al. 2018

Metals

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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.

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Section: Dealloying Of Series 2 In 004 M H 2 Sosupporting

confidence: 82%

Dealloying of Cu-Mg-Ca Alloys

Mbarek

Pineda

Escoda

et al. 2018

Metals

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“…One such class is NP metals, typically synthesized by an (electro)chemical etching process known as dealloying, in which the sacrificial component of an alloy is selectively removed to form a bicontinuous network of struts (ligaments) and channels (pores), both with characteristic diameter in the nanoscale range. 87,[119][120][121][122][123][124][125][126][127] Advances in tomography techniques have enabled 3D reconstruction of several NP metals; these findings indicate that the ligament and pore structures are inverse of one another and are morphologically and topologically equivalent, and thus exhibit the so-called bicontinuous structure. [128][129][130] Computation of NP metal structures with Kinetic Monte Carlo, molecular dynamics, and phase field methods yield similar results.…”

Section: Models For Nanoporous Materials With a Strong Scattering Peakmentioning

confidence: 99%

Small-angle X-ray scattering of nanoporous materials

Welborn

Detsi

2020

Nanoscale Horiz.

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“…The more fundamental parameterL relates to an underlying wavelength and can therefore be determined from information in reciprocal space. Experiment provides such information in the form of peak positions in small-angle scattering [37,38,57] or in Fourier transforms of electron micrographs [23]. YetL is rarely reported in experimental studies.…”

Section: Kinetics Of Coarsening and Appropriate Size Parametermentioning

confidence: 99%

Topology evolution during coarsening of nanoscale metal network structures

Ngô

Markmann

et al. 2019

Phys. Rev. Materials

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Many experiments exploit curvature-driven, surface-diffusion-mediated coarsening for tuning the characteristic structure size of metal network structures made by dealloying, such as nanoporous gold. Here we study this process by kinetic Monte Carlo simulation. The initial microstructures are leveled Gaussian random fields, approximating spinodally decomposed mixtures, of different solid fraction ϕ. Earlier work establishes these structures as valid representations of the nanoporous gold microstructure. We find that the coarsening law for the characteristic spacing between the ligaments of the network is universal, whereas the time evolution of the characteristic ligament diameter is not. The expected time exponent 1/4 is confirmed by our simulation. Contrary to what may be expected based on continuum models, the degree of surface faceting or roughness has no apparent effect on the coarsening kinetics. In the time interval of our study, the network connectivity-as measured by a scaled density of topological genus-remains sensibly invariant for networks with ϕ 0.3, consistent with previous reports of a self-similar evolution of the microstructure during coarsening. Yet, networks with lesser ϕ lose their connectivity on coarsening and can even undergo a percolation-to-cluster transition. This process is slow for ϕ only little below 0.3 and it accelerates in networks with lesser ϕ. The dependency of the connectivity evolution on ϕ may explain controversial findings on the microstructure evolution of nanoporous gold in experimental studies.

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X-ray studies of nanoporous gold: Powder diffraction by large crystals with small holes

Cited by 18 publications

References 89 publications

Dealloying of Cu-Mg-Ca Alloys

Dealloying of Cu-Mg-Ca Alloys

Small-angle X-ray scattering of nanoporous materials

Topology evolution during coarsening of nanoscale metal network structures

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