Theoretical analysis of deuterium retention in tungsten plasma-facing components induced by various traps via thermal desorption spectroscopy

Hydrogen is nowadays in focus as an energy carrier that is locally emission free. Especially in combination with fuel-cells, hydrogen offers the possibility of a CO2 neutral mobility, provided that the hydrogen is produced with renewable energy. Structural parts of automotive components are often made of steel, but unfortunately they may show degradation of the mechanical properties when in contact with hydrogen. Under certain service conditions, hydrogen uptake into the applied material can occur. To ensure a safe operation of automotive components, it is therefore necessary to investigate the time, temperature and pressure dependent hydrogen uptake of certain steels, e.g., to deduct suitable testing concepts that also consider a long term service application. To investigate the material dependent hydrogen uptake, a tubular autoclave was set-up. The underlying paper describes the set-up of this autoclave that can be pressurised up to 20 MPa at room temperature and can be heated up to a temperature of 250 °C, due to an externally applied heating sleeve. The second focus of the paper is the investigation of the pressure dependent hydrogen solubility of the martensitic stainless steel 1.4418. The autoclave offers a very fast insertion and exertion of samples and therefore has significant advantages compared to commonly larger autoclaves. Results of hydrogen charging experiments are presented, that were conducted on the Nickel-martensitic stainless steel 1.4418. Cylindrical samples 3 mm in diameter and 10 mm in length were hydrogen charged within the autoclave and subsequently measured using thermal desorption spectroscopy (TDS). The results show how hydrogen sorption curves can be effectively collected to investigate its dependence on time, temperature and hydrogen pressure, thus enabling, e.g., the deduction of hydrogen diffusion coefficients and hydrogen pre-charging concepts for material testing.

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Fluence Dependence of Surface Morphology and Deuterium Retention in W Bulks and Nanocrystalline W Films Exposed to Deuterium Plasma

Applied Sciences ◽

10.3390/app11041619 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1619

Author(s):

Jing Yan ◽

Xia Li ◽

Kaigui Zhu

Keyword(s):

Surface Morphology ◽

Thermal Desorption Spectroscopy ◽

Low Energy ◽

High Flux ◽

Deuterium Plasma ◽

Vacancy Clusters ◽

Plasma Irradiation ◽

Deuterium Retention ◽

Fluence Dependence ◽

Scanning Electron

The surface morphology of pure W bulks and nanocrystalline tungsten films was investigated after exposure to a low-energy (100 eV/D), high-flux (1.8 × 1021 D·m−2s−1) deuterium plasma. Nanocrystalline tungsten films of 6 μm thickness were deposited on tungsten bulks and exposed to deuterium plasma at various fluences ranging from 1.30 × 1025 to 5.18 × 1025 D·m−2. Changes in surface morphology from before to after irradiation were studied with scanning electron microscopy (SEM). The W bulk exposed to low-fluence plasma (1.30 × 1025 D·m−2) shows blisters. The blisters on the W bulk irradiated to higher-fluence plasma are much larger (~2 µm). The blisters on the surface of W films are smaller in size and lower in density than those of the W bulks. In addition, the modifications exhibit the appearance of cracks below the surface after deuterium plasma irradiation. It is suggested that the blisters are caused by the diffusion and aggregation of the deuterium-vacancy clusters. The deuterium retention of the W bulks and nanocrystalline tungsten films was studied using thermal desorption spectroscopy (TDS). The retention of deuterium in W bulks and W films increases with increasing deuterium plasma fluence when irradiated at 500 K.

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The Role of Cr in H Desorption Kinetics in Rapidly Solidified Al

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.264 ◽

2014 ◽

Vol 783-786 ◽

pp. 264-269 ◽

Cited By ~ 3

Author(s):

Iya I. Tashlykova-Bushkevich ◽

Keitaro Horikawa ◽

Goroh Itoh

Keyword(s):

High Temperature ◽

Thermal Desorption ◽

High Purity ◽

Thermal Desorption Spectroscopy ◽

Secondary Phase ◽

Hydrogen Desorption ◽

Oxide Surface ◽

Desorption Kinetics ◽

Hydrogen Trapping ◽

Rapidly Solidified

Hydrogen desorption kinetics for rapidly solidified high purity Al and Al-Cr alloy foils containing 1.0, 1.5 and 3.0 at % Cr were investigated by means of thermal desorption analysis (TDA) at a heating rate of 3.3°C/min. For the first time, it was found that oxide inclusions of Al2O3 are dominant high-temperature hydrogen traps compared with pores and secondary phase precipitates resulted in rapid solidification of Al and its alloys. The correspondent high-temperature evolution rate peak was identified to be positioned at 600°C for high purity Al and shifted to 630°C for Al-Cr alloys. Amount of hydrogen trapped by dislocations increases in the alloys depending on Cr content. Microstructural hydrogen trapping behaviour in low-and intermediate temperature regions observed here was in coincidence with previous data obtained for RS materials using thermal desorption spectroscopy (TDS). The present results on hydrogen thermal desorption evolution indicate that the effect of oxide surface layers becomes remarkable in TDA measurements and show advantages in combinations of both desorption analysis methods to investigate hydrogen desorption kinetics in materials.

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