scholarly journals Development of Experimental Chamber for Testing High-Temperature Hydrogen Permeation through Metal Foils

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1314
Author(s):  
Viktor Kudiiarov ◽  
Ivan Sakvin ◽  
Georgy Garanin ◽  
Andrey Lider
Keyword(s):  
Diffusion Coefficient ◽  
High Temperature ◽  
Hydrogen Pressure ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Diffusion Chamber ◽  
Experimental Chamber ◽  
Metal Foils ◽  
Diffusion Curve ◽  
Fick Equation

This paper describes the methodology for conducting experiments to study hydrogen diffusion through metal membranes using a specially designed diffusion chamber of an automated gas reaction controller complex. This complex allows experiments to study hydrogen diffusion with the following parameters: the inlet hydrogen pressure is up to 50 atmospheres, and the temperature in the chamber is from 30 °C to 1000 °C. The size of the samples is limited to a diameter of 10 mm and a thickness of 100 μm. The method for calculating the diffusion coefficient based on the Fick equation is also described. When studying hydrogen diffusion through a sample of Zr–1Nb alloy with nickel film deposited at the temperature of 550 °C, it was noted that phase transformations can be observed on the diffusion curve.

Hydrogen Diffusion Coefficient during Hydrogen Permeation through Nb-Based Hydrogen Permeable Membranes

2009 ◽  
Vol 283-286 ◽  
pp. 225-230 ◽  
Author(s):  
Hiroshi Yukawa ◽  
G.X. Zhang ◽  
N. Watanabe ◽  
Masahiko Morinaga ◽  
T. Nambu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffusion Coefficient ◽  
High Temperature ◽  
Solid Solutions ◽  
Diffusion Coefficients ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Pure Niobium ◽  
Hydrogen Diffusion Coefficient

The hydrogen diffusion coefficients are investigated during the hydrogen permeation through Nb-based hydrogen permeable membranes at high temperature. It is found that the hydrogen diffusion coefficient for pure niobium under practical conditions is much lower than the reported values measured for dilute hydrogen solid solutions. Surprisingly, the hydrogen diffusion is found to be faster in Pd-Ag alloy with fcc crystal structure than in pure niobium with bcc crystal structure at 773K during the hydrogen permeation. It is also found that the addition of Ru or W into niobium increases the hydrogen diffusion coefficient under the practical conditions.

Hydrogen Diffusivity and Solubility in Internally Oxidized Pd0.97Zr0.03 and Pd0.97Nb0.03 Alloys

2010 ◽  
Vol 297-301 ◽  
pp. 715-721
Author(s):  
E.R. Lagreca ◽  
Viviane M. Azambuja ◽  
Dílson S. dos Santos
Keyword(s):  
Diffusion Coefficient ◽  
Grain Boundaries ◽  
Hydrogen Pressure ◽  
Hydrogen Diffusion ◽  
Gas Permeation ◽  
Hydrogen Diffusivity ◽  
Sem Images ◽  
Conventional Furnace ◽  
Hydrogen Diffusion Coefficient ◽  
Preferential Segregation

Internally oxidized (I.O.) Pd0.97Zr0.03 and Pd0.97Nb0.03 alloys were submitted to gas permeation tests with temperatures in the range of 473-873 K. The internal oxidation was kept in a conventional furnace at 1073 K for 24 hours in air contact. The formation of nano-oxides, ZrO2 and Nb2O5, dispersed in the Pd matrix was observed. SEM images showed a preferential segregation of these oxides in the grain boundaries. It was observed that the diffusion coefficient in the sample containing Nb oxide was smaller than that in the Pd-Zr oxide. The effect of hydrogen pressure was investigated in the Pd-Nb samples. It was observed that the hydrogen diffusion coefficient increases with increasing the pressure. The hydrogen solubility is bigger for the Pd-Zr internally oxidized. This effect is attributed to the Zr nanoxides, which are smaller than Pd-Nb precipitates and then offer more interface for trapping the hydrogen.

scholarly journals Hydrogen Diffusivity in Different Microstructures of 42CrMo4 Steel

Hydrogen ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 414-427
Author(s):  
Atif Imdad ◽  
Alfredo Zafra ◽  
Victor Arniella ◽  
Javier Belzunce
Keyword(s):  
Diffusion Coefficient ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Ferritic Steels ◽  
Hydrogen Diffusivity ◽  
Hydrogen Atoms ◽  
Hydrogen Diffusion Coefficient ◽  
Microstructural Defects ◽  
42Crmo4 Steel

It is well known that the presence of hydrogen decreases the mechanical properties of ferritic steels, giving rise to the phenomenon known as hydrogen embrittlement (HE). The sensitivity to HE increases with the strength of the steel due to the increase of its microstructural defects (hydrogen traps), which eventually increase hydrogen solubility and decrease hydrogen diffusivity in the steel. The aim of this work is to study hydrogen diffusivity in a 42CrMo4 steel submitted to different heat treatments—annealing, normalizing and quench and tempering—to obtain different microstructures, with a broad range of hardness levels. Electrochemical hydrogen permeation tests were performed in a modified Devanathan and Stachursky double-cell. The build-up transient methodology allowed the determination of the apparent hydrogen diffusion coefficient, Dapp, and assessment of its evolution during the progressive filling of the microstructural hydrogen traps. Consequently, the lattice hydrogen diffusion coefficient, DL, was determined. Optical and scanning electron microscopy (SEM) were employed to examine the steel microstructures in order to understand their interaction with hydrogen atoms. In general, the results show that the permeation parameters are strongly related to the steel hardness, being less affected by the type of microstructure.

Analysis of hydrogen diffusion coefficient during hydrogen permeation through niobium and its alloys

2009 ◽  
Vol 476 (1-2) ◽  
pp. 102-106 ◽  
Author(s):  
H. Yukawa ◽  
G.X. Zhang ◽  
N. Watanabe ◽  
M. Morinaga ◽  
T. Nambu ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Hydrogen Diffusion Coefficient

Development of Stand for Testing Electrochemical Permeation (STEP) of Hydrogen through Metal Foils

2015 ◽  
Vol 1085 ◽  
pp. 224-228
Author(s):  
Viktor N. Kudiiarov ◽  
Natalia S. Pushilina ◽  
S.Y. Harchenko
Keyword(s):  
Diffusion Coefficient ◽  
Electron Beam ◽  
Electron Beam Irradiation ◽  
Hydrogen Diffusion ◽  
Protective Oxide ◽  
Pulsed Electron Beam ◽  
Metal Foils ◽  
Experimental Stand ◽  
Hydrogen Diffusion Coefficient ◽  
Protective Oxide Film

Experimental Stand for Testing Electrochemical Permeation (STEP) of hydrogen through metal foils was constructed and described in this paper. Hydrogen diffusion coefficients in different metal foils at room temperature can be determined by using STEP. Influence of pulsed electron beam irradiation on hydrogen diffusion coefficient in zirconium alloy E110 was investigated. It was established that treatment by pulsed electron beam with the energy density of 18 J/cm2, by three impulses with duration 50 μs leads to a decrease in the diffusion coefficient of hydrogen on the order of one. This is due to the fact that structure with more branched crystals’ boundary formed after irradiation and such structure is effective trap for hydrogen. Also there is formation of protective oxide film after irradiation.

Alloying Effects on the Hydrogen Diffusivity during Hydrogen Permeation through Nb-Based Hydrogen Permeable Membranes

2010 ◽  
Vol 297-301 ◽  
pp. 1091-1096 ◽  
Author(s):  
Hiroshi Yukawa ◽  
G.X. Zhang ◽  
Masahiko Morinaga ◽  
T. Nambu ◽  
Yoshihisa Matsumoto
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Hydrogen Permeability ◽  
Hydrogen Diffusivity ◽  
Hydrogen Flux ◽  
Pure Niobium ◽  
Hydrogen Diffusion Coefficient ◽  
Alloying Effects

The hydrogen solubility and the hydrogen permeability have been measured for Nb-based alloys in order to investigate the alloying effects on the hydrogen diffusivity during hydrogen permeation. The hydrogen diffusion coefficient during hydrogen permeation is estimated from a linear relationship between the normalized hydrogen flux, , and the difference of hydrogen concentration, C, between the inlet and the outlet sides of the membrane. It is found that the hydrogen diffusion coefficient during the hydrogen permeation is increased by alloying ruthenium or tungsten into niobium. On the other hand, the activation energy for hydrogen diffusion in pure niobium under the practical permeation condition is much higher than the reported values measured for dilute hydrogen solid solutions. It is interesting that the activation energy for hydrogen diffusion decreases by the addition of ruthenium or tungsten into niobium.

Studies on Hydrogen Permeation of Weldments for Two Low-Alloyed Steels With Different Microstructures

2011 ◽  
Author(s):  
Jian Qun Tang ◽  
Jian Ming Gong
Keyword(s):  
Diffusion Coefficient ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Lath Martensite ◽  
Hydrogen Permeability ◽  
Diffusion Path ◽  
Permeation Rate ◽  
Liquefied Petroleum Gas ◽  
Boundary Area ◽  
And Diffusion

16MnR and SPV50Q low-alloyed steels, which have ferrite-pearlite and tempered martensite microstructures, respectively, are widely used to fabricate storage tanks for liquefied petroleum gas. However, during the process of operation, some cracks often occur on tanks made by these steels due to the presence of hydrogen, especially on weldments. The occurrence of this cracking is closely related to the diffusion and permeation of hydrogen in the steels. In order to explore the effect of different microstructures on hydrogen permeation and compare the hydrogen permeability of these two weldments, measurements were conducted on various metals (base metal-BM, heat-affected zone-HAZ, and welded metal-WM) cut from 16MnR and SPV50Q weldments by using electrochemical permeation tests. The results show that the microstructure has an important effect on hydrogen permeability. For 16MnR steel weldment, the diffusion coefficient of BM is the minimum due to the presence of the strong hydrogen traps in the interface between banded pearlite and matrix as well as the interface between inclusion and matrix. The microstructure of WM provides great grain boundary area as a hydrogen diffusion path and makes hydrogen easily diffuse, which results in the maximum permeation rate and diffusion coefficient. The fine-grained microstructure of normalized zone in HAZ acts as barriers for the hydrogen diffusion, which makes the permeation rate and diffusion coefficient of HAZ located between those of BM and WM. Similarly, for SPV50Q weldment, the permeation rate and diffusion coefficient increase in the order of BM, HAZ and WM. Those of BM are the minimum, which is correlated with the strong hydrogen trap due to the large quantities of dislocation within the lath martensite. Those of WM are the maximum for its strongly hydrogen diffusion path like WM of 16MnR weldment. As comparing the hydrogen permeability of 16MnR and SPV50Q weldment, the corresponding metals of the former always have greater permeation rate and diffusion coefficient than those of the latter, which is also due to its intrinsic microstructures.

Analysis of hydrogen diffusion coefficient during hydrogen permeation through pure niobium

2008 ◽  
Vol 33 (16) ◽  
pp. 4419-4423 ◽  
Author(s):  
G ZHANG ◽  
H YUKAWA ◽  
N WATANABE ◽  
Y SAITO ◽  
H FUKAYA ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Pure Niobium ◽  
Hydrogen Diffusion Coefficient
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