Effect of powder granulation on hydrogen transport rate and hydrogen solubility in LaNi5-paraffin composite material

2012 ◽  
Vol 57 (3) ◽  
pp. 727-731 ◽  
Author(s):  
I. Kukuła ◽  
H. Bala
Keyword(s):  
Hydrogen Diffusion ◽  
Diffusion Rate ◽  
Solid Phase ◽  
Hydrogen Transport ◽  
Composite Electrodes ◽  
Apparent Diffusion ◽  
Deaerated Solution ◽  
Powder Particles ◽  
Discharge Method ◽  
Spherical Diffusion

On the basis of potentiostatic discharge method, the diffusion rate of atomic hydrogen as well as its solubility in LaNi5 crystal lattice have been evaluated for three LaNi5 powder - paraffin composite electrodes, with different LaNi5 powder particle diameters: 0 - 20 μm, 20 - 50 μm and 50 - 100 μm. The chronoamperommetric tests have been carried out in strong alkaline (6 M KOH), deaerated solution, at 25°C. Apparent hydrogen diffusion coefficients have been determined using Crank’s spherical diffusion model. It has been shown, that increase of particle size is prone to increase of hydrogen apparent diffusion coefficient and to decrease of hydrogen concentration in the solid phase. To explain the granulation effect on hydrogenation ability parameters, the inhibition of hydrogen transport by surfacial corrosion products present on powder particles has been assumed.

Some Notes on Hydrogen Blistering ★—A Technical Note

CORROSION ◽  
1954 ◽  
Vol 10 (3) ◽  
pp. 101-102 ◽  
Keyword(s):  
Electric Furnace ◽  
Atomic Hydrogen ◽  
Hydrogen Diffusion ◽  
Diffusion Rate ◽  
Technical Note ◽  
Acidic Solutions ◽  
Grade Steel

Abstract Data were obtained on the diffusion of atomic hydrogen through several kinds of steel in acidic solutions. Where diffusion occurred, the presence of sulfide increased the diffusion rate. In an electric furnace grade steel, diffusion did not take place unless sulfide was present. Observations were made on the permanene of the sulfide surface associated with rapid atomic hydrogen diffusion.

Diffusion and Solubility of Hydrogen in Amorphous and Microcrystalline Si:H Films

2001 ◽  
Vol 664 ◽  
Author(s):  
Wolfhard Beyer
Keyword(s):  
Hydrogen Diffusion ◽  
Silicon Films ◽  
Hydrogen Solubility ◽  
Hydrogen Transport ◽  
Microcrystalline Silicon ◽  
Hydrogen Incorporation ◽  
Hydrogenated Amorphous

ABSTRACTHydrogen diffusion and solubility effects in hydrogenated amorphous and microcrystalline silicon films are reviewed. Various diffusion-related effects have been observed which need to be considered in models of hydrogen diffusion. Hydrogen solubility is found to affect hydrogen incorporation and hydrogen transport.

Facile Synthesis of Cobalt Oxide Uniformly Coated on Multi-Wall Carbon Nanotubes for Supercapacitors

2011 ◽  
Vol 306-307 ◽  
pp. 1148-1152 ◽  
Author(s):  
Liang Yu Gong ◽  
Ling Hao Su
Keyword(s):  
Carbon Nanotubes ◽  
Cobalt Oxide ◽  
Solid Phase ◽  
Synthesis Method ◽  
Electrochemical Performances ◽  
Composite Electrodes ◽  
Phase Synthesis ◽  
Multi Wall Carbon Nanotubes ◽  
Electrochemical Tests ◽  
Transmission Electron

The composite electrodes of cobalt oxide and multi-wall carbon nanotubes (MWCNTs) are prepared by a simple low-temperature solid-phase synthesis method with the assistance of polyethylene glycol and their pseudocapacitive performances are investigated in alkaline solution by cyclic voltammetry and galvanostatic charge/discharge tests, respectively. Transmission electron microscope images show that cobalt oxide is uniformly coated on multi-wall carbon nanotubes and the homogeneous hybrid nanostructure are considered to be responsible for their preferable electrochemical performances. The electrochemical tests further reveal that the composite can deliver a maximum specific capacitance of 217 F/g with a biggest utilization of Co element when the content of MWCNTs increases to 50 wt.%.

Hydrogen Transport in Phosphorus and Boron Dopedpolycrystalline Silicon

1999 ◽  
Vol 557 ◽  
Author(s):  
N. H. Nickel ◽  
I. Kaiser
Keyword(s):  
Polycrystalline Silicon ◽  
Hydrogen Diffusion ◽  
Effective Diffusion ◽  
Single Crystal Silicon ◽  
Hydrogen Transport ◽  
Crystal Silicon ◽  
Thermally Activated ◽  
Boron Doped ◽  
Similar Dependence ◽  
Formation Energies

AbstractHydrogen diffusion in phosphorus and boron doped polycrystalline silicon was investigated by deuterium diffusion experiments. The presence of dopants enhances hydrogen diffusion. The effective diffusion coefficient Deff is thermally activated and the activation energy varies between 0.1 and 0.4 eV. This is accompanied by a variation of the diffusion prefactor by 12 orders of magnitude. Using the theoretical diffusion prefactor the actual energy EA was calculated from Deff.EA also depends strongly on the Fermi energy and exhibits a similar dependence as the formation energies of H+ and H- in single crystal silicon.

scholarly journals Molecular Dynamics and Monte Carlo simulations resolve apparent diffusion rate differences for proteins confined in nanochannels

2015 ◽  
Vol 457 ◽  
pp. 19-27 ◽  
Author(s):  
J.W. Tringe ◽  
N. Ileri ◽  
H.W. Levie ◽  
P. Stroeve ◽  
V. Ustach ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Diffusion Rate ◽  
Apparent Diffusion

Comparison of Decoupled and Coupled Analyses for Hydrogen Transport in Fracture Specimens

2007 ◽  
Author(s):  
Y. Kim ◽  
Y. J. Chao ◽  
M. J. Morgan ◽  
P.-S. Lam
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Concentration ◽  
Hydrogen Diffusion ◽  
Constitutive Models ◽  
Coupled Model ◽  
Hydrogen Transport ◽  
Blunt Crack ◽  
The Difference ◽  
Point Bend ◽  
Fracture Specimens

Hydrogen embrittlement is an important issue in many industries. Fracture resistance of metals is often weakened by the presence of hydrogen. In this paper, two diffusion models are compared for hydrogen transport analysis. One is the coupled model where the concentration of hydrogen in the lattice is integrated with mechanical properties. The other is the decoupled model in which the hydrogen diffusion is independent of the mechanical properties; but depends on the stress state. Finite element analyses are performed for a boundary layer specimen with a blunting crack and a four-point bend specimen with rounded notch. Hydrogen concentration profiles around the blunt crack (or notch) are compared under different boundary conditions and material properties. It is observed that, in spite of the difference in constitutive models, there is a similarity between hydrogen concentration in normal interstitial sites by the two models. In case that large plastic strain is present (such as those in low to moderate strength steels) there is a substantial difference in hydrogen concentration between the two models.

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