Correlation between surface tension, density, and sound velocity of liquid metals

Blairs, S.

doi:10.1016/j.jcis.2006.06.025

Cited by 60 publications

(29 citation statements)

References 15 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The parameter γ compares well with the experimental values of the surface tension of bulk Fe at the melting point ∼ 1.85 J/m 242 and ∼1.90 43 . For a detailed explanation of the "size-pressure approximation" see Ref.…”

supporting

confidence: 76%

Influence of Mo on the Fe:Mo:C nanocatalyst thermodynamics for single-walled carbon nanotube growth

et al. 2008

View full text Add to dashboard Cite

We explore the role of Mo in Fe:Mo nanocatalyst thermodynamics for low-temperature chemical vapor deposition growth of single walled carbon nanotubes (SWCNTs). By using the size-pressure approximation and ab initio modeling, we prove that for both Fe-rich (∼ 80% Fe or more) and Mo-rich (∼ 50% Mo or more) Fe:Mo clusters, the presence of carbon in the cluster causes nucleation of Mo2C. This enhances the activity of the particle since it releases Fe, which is initially bound in a stable Fe:Mo phase, so that it can catalyze SWCNT growth. Furthermore, the presence of small concentrations of Mo reduce the lower size limit of low-temperature steady-state growth from ∼0.58nmf orpureF eparticlesto ∼ 0.52nm. Our ab initio-thermodynamic modeling explains experimental results and establishes a new direction to search for better catalysts.Critical factors for the efficient growth of single walled carbon nanotubes (SWCNTs) via catalytic chemical vapor deposition (CCVD) 1,2,3 are the compositions of the interacting species (feedstock, catalyst, support 4,5,6,7,8,9,10 ), the preparation of the catalysts, and the synthesis conditions 11,12,13,14,15,16,17,18 . Efficient catalysts must have long active lifetimes (with respect to feedstock dissociation and nanotube growth), high selectivity and be less prone to contamination 19,20,21,22,23 . Common factors that lead to reduction in catalytic activity are deactivation (i.e. chemical poisoning or coating with carbon), thermal sintering (e.g. caused by highly exothermic reactions on the clusters surface 13,14,24 with insufficient heat transfer 25,26 ) and solid-state reactions (nucleation of inactive phases in the cluster 22,23,25 ).Metal alloy catalysts, such as Fe:Co, Co:Mo and Fe:Mo, improve the growth of CNTs 4,10,20,27,28,29,30,31 , because the presence of more than one metal species can significantly enhance the activity of a catalyst 20,32,33,34 , and can prevent catalyst particle aggregation 20,31,32,33 . In the case of Fe:Mo nanoparticles supported on Al 2 O 3 substrates, the enhanced catalyst activity has been shown to be larger than the linear combination of the individual Fe/Al 2 O 3 and Mo/Al 2 O 3 activities 20,27,28 . This is explained in terms of substantial inter-metallic interaction between Mo, Fe and C 20,35,36 which is congruent with previously observed solid-state reactions between these elements. In fact, the addition of Mo in mechanical alloying of powder Fe and C mixtures 38 promotes solid state reactions even at low Mo concentrations by forming ternary phases, such as the (Fe,Mo) 23 C 6 type carbides 38 .The way in which carbon interacts with transition metals depends on the metal species. Fe and Co belong to the "carbon dissolution-precipitation mechanism" group, where relatively large fractions of carbon dissolve into the cluster before stable carbides are formed, while Mo belongs to the "carbide formation-decomposition" group where carbide formation occurs rapidly at low carbon concentrations 39 . These mechanisms are governed by the interplay between solub...

show abstract

supporting

confidence: 76%

Influence of Mo on the Fe:Mo:C nanocatalyst thermodynamics for single-walled carbon nanotube growth

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The last mentioned was calculated taking into account thermal expansion, p  , and the constant pressure specific heat, p C , data [37,55], respectively. The ratio between the isobaric and isochoric heat capacities is the coefficient of proportionality that relates the adiabatic compressibility to the isothermal compressibility of pure components [56].…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Thermodynamic, surface and structural properties of liquid Co-Si alloys

Novaković

Giuranno

Caccia

et al. 2016

Journal of Molecular Liquids

View full text Add to dashboard Cite

The knowledge of thermophysical properties of liquid Co-Si alloys is a key requirement for manufacturing of composite materials by infiltration method. Despite this need, the experimental and predicted property data of the Co-Si system are scarce and often inconsistent between the various sources. In the present work the mixing behaviour of Co-Si melts has been analyzed through the study of the concentration dependence of various thermodynamic, surface (surface tension and surface composition) and structural properties (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter) in the framework of the Compound Formation Model (CFM) and Quasi Chemical Approximation for regular solutions (QCA). In addition, the surface tension of the Co 22.5 Si 77.5 (in at %) eutectic alloy, that is proposed to be used as the infiltrant, has been measured by the pendant drop method at temperatures ranging from 1593 to 1773 K. The results obtained were discussed with respect to both, temperature and concentration, and subsequently compared with the model predictions and literature data.

show abstract

“…This anisotropy could be also related to the anomalous electronic-topological transition observed at high pressure [20] and it makes liquid zinc a good candidate for displaying a complex dynamics. From the experimental point of view, Zn is an almost coherent neutron scatterer with a melting temperature Tm = 693 K. In the hydrodynamic limit, the longitudinal sound velocity at the melting point is v°L = 2850 m /s [21], This fairly high value is well within the range of the time-of-flight neutron Brillouin spectrometer BRISP [22][23][24], installed at the Institut Laue Langevin research reactor (Grenoble, France) and properly designed to perform INS experiments at small momentum transfer Q. Experimental results reveal a com plex dynamics, showing the existence of two distinct modes.…”

mentioning

confidence: 99%

Collective Ion Dynamics in Liquid Zinc: Evidence for Complex Dynamics in a Non-Free-Electron Liquid Metal

et al. 2015

View full text Add to dashboard Cite

A detailed inelastic neutron scattering investigation of the THz dynamics of liquid zinc is presented. The observed Q dependence clearly reveals the existence of a complex dynamics made up of two distinct excitations. The highest energy mode is the prolongation of the longitudinal acoustic density fluctuations whereas the comparison with the phonon dynamics of crystalline hcp zinc suggests a transverse acousticlike nature for the second one. This mode seems related to peculiar anisotropic interactions, possibly connected to the behavior of the crystalline phase.

show abstract

Correlation between surface tension, density, and sound velocity of liquid metals

Cited by 60 publications

References 15 publications

Influence of Mo on the Fe:Mo:C nanocatalyst thermodynamics for single-walled carbon nanotube growth

Influence of Mo on the Fe:Mo:C nanocatalyst thermodynamics for single-walled carbon nanotube growth

Thermodynamic, surface and structural properties of liquid Co-Si alloys

Collective Ion Dynamics in Liquid Zinc: Evidence for Complex Dynamics in a Non-Free-Electron Liquid Metal

Contact Info

Product

Resources

About