Using Ball Milling for Modification of the Hydrogenation/Dehydrogenation Process in Magnesium-Based Hydrogen Storage Materials: An Overview

Magnesium-based hydrogen storage materials are considered to be one of the most promising solid-state hydrogen storage materials due to their large hydrogen storage capacity and low cost. However, slow hydrogen absorption/desorption rate and excessive hydrogen absorption/desorption temperature limit the application of magnesium-based hydrogen storage materials. The present paper reviews recent progress in improving the hydrogen storage properties by element substitution and additives. Ball milling is the promising technology for preparing magnesium-based hydrogen storage materials. The research and development of approaches for modifying magnesium-based hydrogen storage materials prepared by ball milling is systematically expounded. It is concluded that ball milling can significantly improve the kinetic and electrochemical properties of magnesium-based hydrogen storage materials and increase the hydrogen storage capacity. In the future, the research of magnesium-based hydrogen storage materials should be developed in terms of hydrogen storage mechanism, computer design of materials and development of a more optimized catalytic system

Pressure and Temperature Effect on Hydrogen Sorption of Carbon Material

The paper presents the experimental results of saturation of the carbon material containing nanotubes with hydrogen from the gas. The dependences of hydrogen concentration from pressure (from 0 to 8 atmospheres), at the same temperature for adsorption (-30 degrees Celsius) and different temperatures for desorption were obtained. The temperature has an influence on sorption-desorption process and sorption properties of carbon material. The amount of residual hydrogen depends on saturation parameters

Control of changes in the defect structure of titanium saturated with hydrogen

The hydrogenated samples of technical titanium were investigated using the EPA method and the measurements of the thermal electromotive force for these samples saturated with a different amount of hydrogen. The structure of the hydrogenated samples was studied by the X-ray diffraction method. The results have shown that the hydrogenated titanium structure starts changing at the same time, depending on the amount of added hydrogen. The intensity of the annihilation process increases with the increase in the hydrogen concentration in a-titanium up to the values of 4% wt and does not change up to the values of 5% wt ([alpha]+[beta]) - titanium. At the same time, the value of the thermal electromotive force decreases in this range of values. The annihilation intensity is stabilized for the values of 5% wt, and the value of the thermal electromotive force is increased. The inflection point for the thermal electromotive force versus the hydrogen concentration corresponds to the formation of [delta] - hydrides. The increase in the positron lifetime starts in the concentration range of 6-8% and moves to the stable level up to the concentrations of 21-22%. In this range, there is a transition from the wt ([alpha]+[beta]) to the wt ([alpha]+[delta) phase. The lifetime of positrons and the number of defects are increased, the value of the thermal electromotive force is reduced (up to the concentration of 24%), then there is a stabilization mode for all these parameters up to the values 32% wt

Compulsory Checking of Nuclear Power Engineering Materials by Direct and Eddy Current

The testing technology of copper parts designed for dry storage of spent nuclear fuel with application of direct and eddy current has been developed. Measurements results of flaw quantity caused hydrogenation and oxidation processes are presented. Evolution of copper M 001 flaw structure during hydrogenation from gaseous medium is analyzed. It has been demonstrated that the dependence of copper p electrical resistance on number of flaws in its structure has dome shaped character and changes with eddy current frequency change. Number of flaws formed by hydrogen depends on direction (100) or (200) of the crystal structure of copper lattice

Thermo-Electromotive Force and Electrical Resistivity of Hydrogenated VT1-0 Titanium Alloy

The method for measuring the structure transition of hydrogenated titanium from one state to another is suggested. The method is based on the comparison of thermo-electromotive force (thermo-emf), DC electrical resistance and the results of X-ray diffraction analysis. X-ray diffraction analysis is applied for identifying the quantity of defects in titanium structure. The authors have also identified the identical dependence of thermo-electromotive force and electrical resistivity on hydrogen concentration in titanium. The effect can be used for hydrogenated titanium structure control

The Classification of Weld Seam Defects for Quantitative Analysis by means of Ultrasonic Testing

The paper describes effective quality assessment of spent nuclear fuel storage cask. The ultrasonic testing method is considered. The classification of possible defects with corresponding dimensions limits is proposed. The database of defects of the spent nuclear fuel storage cask was created in compliance with the nuclear energy industry regulatory documents

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

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 accumulation and distribution during the saturation of a VT1-0 titanium alloy by an electrolytic method and from a gas atmosphere

The accumulation, distribution, and thermally stimulated release of hydrogen in a VT1-0 titanium alloy during electrolytic saturation and gas-phase saturation are studied. After electrolytic saturation, a 0.4-μm-thick surface layer consisting of δ hydrides with a binding energy of 108 kJ/mol forms in the alloy. The hydride dissociation after electrolytic saturation in heating occurs in the temperature range 320-370°C. After saturation from a gas atmosphere, δ hydrides with a binding energy of 102 kJ/mol form throughout the alloy volume. The dissociation of the hydrides formed during gas-phase saturation in heating occurs in the temperature range 520-530°C. A further increase in the temperature is accompanied by the transformation of titanium from the α into the β modification. At 690-720°C, the phase transformation is completed, and another hydrogen desorption peak appears in a thermally stimulated hydrogen desorption spectrum

Application of Automated Complex Gas Reaction Controller for Hydrogen Storage Materials Investigation

Automated complex Gas Reaction Controller and its application for hydrogen storage materials investigation are described in this article. Pressure-composition isotherms (PCI) and kinetics measurements of LaNi5 have been obtained for validation of the apparatus. Measurements of both absorption and desorption PCI curves and kinetics measurements at different conditions have been obtained for carbon nanotubes to estimate its hydrogen storage properties

Digitally focused array ultrasonic testing technique for carbon fiber composite structures

Composite fiber reinforced polymers are highly promising structures. At present, they are widely used in different areas such as aeronautics and nuclear industries. There is a great number of advantages of composite structures such as design flexibility, low cost per cubic inch, resistance to corrosion, lower material costs, lighter weight and improved productivity. However, composites degradation may be caused by different mechanisms such as overload, impact, overheating, creep and fatigue. Comparing to inspection of other materials some unique consideration is required for testing and analysis. Ultrasound testing is the most common method for inspection of composite structures. Digitally Focused Array Technology is considered as novel approach which enables fast and effective quantitative automatic testing. In this study new methodology of quality assurance of composite structure components based on DFA is performed