Li-D films co-deposited from deuterium plasma were investigated. It was found that the D concentration has the dependence on the deposition temperature with a maximum of similar to 30 at. % at 350-500 K. Lithium mass deposited on the substrate decreases rapidly at deposition temperatures above 570 K. In the narrow range of 520-570 K lithium collection is still efficient and deuterium accumulation is already low, so the temperatures in the range are optimal for lithium collectors in fusion devices. Deuterium in the films is mainly in the form of lithium deuteride with small amounts of D is solution and in lithium hydroxide and lithium hydronitrides.

A setup for investigation of thermal desorption spectra of gases accumulated in thin films deposited by plasma sputtering of solid targets is described. Deposition and thermal desorption spectroscopy (TDS) are performed in two different vacuum chambers separated by a gate valve with the sample transferred between the chambers in-vacuo. The temperature of the substrate for deposited films can be varied in the range of 300-800 K; and the deposition rate is controlled by a quartz microbalance. Thermal desorption of co-deposited gases is analyzed by a quadrupole mass spectrometer. Sputtering rate and evaporation of the film during TDS are measured by quartz microbalances. Three experiments are described 1) trapping of deuterium by the growing chemically active Li film with subsequent decomposition and evaporation of the film, 2) temperature dependent deuterium trapping in the growing W film resulting in trapping with several binding energies, and 3) chemical interaction of D-Li layer with water vapor leading to isotopic H-D exchange and chemical transformation of the deposited film.

Deuterium release from Li-D films co-deposited on a Mo substrate at room temperature in magnetron discharge was investigated by means of thermal desorption spectroscopy. The deuterium concentration in the films was estimated to be D/Li = (14 +/- 4)%. TDS from Li-D films just after co-deposition had a sharp peak at 670-710K. Exposure of deposited Li-D films in the air at room temperature led to deuterium release. Comparison of release in air, water vapor, nitrogen, and oxygen demonstrated that water plays a major role in deuterium release in the air at low temperatures. (C) 2016 Elsevier B.V. All rights reserved.

Liquid metal plasma facing components (LMPFC) have shown a potential to supplant solid plasma facing components materials in the high heat flux regions of magnetic confinement fusion reactors due to the reduction or elimination of concerns over melting, wall damage, and erosion. To design a workable LMPFC, one must understand how liquid metal interacts with solid underlying structures. Wetting is an important factor in such interaction, several designs of LMPFC require liquid metal to wet the underlying solid structures. The wetting of lithium compounds (lithium nitride, oxide, and carbonate) by 200 degrees C liquid lithium at various surface temperature from 230 to 330 degrees C was studied by means of contact angle measurements. Wetting temperatures, defined as the temperature above which the contact angle is less than 90 degrees, were measured. The wetting temperature was 257 degrees C for nitride, 259 degrees C for oxide, and 323 degrees C for carbonate. Surface tensions of solid lithium compounds were calculated from the contact angle measurements. (C) 2016 Elsevier B.V. All rights reserved.

In continuation of a previous study of Li-D films' interactions with atmospheric gases, dynamics of Li-D codeposit interaction with water vapor was studied. Li-D codeposits very actively react with water vapor, leading to formation of LiOH and release of major part of deuterium. The dynamics of the film mass (thickness of the reacted layer) was well described using a diffusion-based model at the early stage of the reaction and using a combined nucleation-diffusion based model in whole period of time. The most of D remaining in the film after exposure to water vapor is released during a heatup below 550 K, that is attributed to LiOH decomposition and occurs at lower temperatures than in the case of initial Li-D film. (C) 2017 Elsevier B.V. All rights reserved.

The interaction between Li–D films obtained via deposition in magnetron discharge with nitrogen and oxygen is investigated. It is shown that exposure to these gases at a pressure of 4000 Pa does not lead to a significant decrease in the amount of deuterium in the film unlike the case of water vapor. The release of deuterium from Li–D films during thermal-desorption analysis occurs mainly in a narrow temperature range at 650–700 K in the case of as-deposited films and after gas exposure. The amplitude of the low-temperature region in the TDS spectrum increases after oxygen exposure.

In this work we investigated co-deposition of lithium-deuterium (Li-D) films in magnetron discharge and interaction of deposited films with water vapor. It was demonstrated that even at room temperature interaction with water vapor led to release of a large portion of deuterium from the deposited layers. After 30 minutes exposure at the pressure about 10 Pa the main part of deuterium released from the sample and a characteristic peak for deuterium desorption from lithium films completely disappeared. © 2015 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) .

In this work we investigated co-deposition of lithium-deuterium (Li-D) films in magnetron discharge and interaction of deposited films with water vapor. It was demonstrated that even at room temperature interaction with water vapor led to release of a large portion of deuterium from the deposited layers. After 30minutes exposure at the pressure about 10−1 Pa the main part of deuterium released from the sample and a characteristic peak for deuterium desorption from lithium films completely disappeared.

A set-up for co-deposition of lithium deuterium mixed films and in situ thermal desorption spectroscopy is described. The set-up consists of a HV chamber with a magnetron discharge for Li-D co-deposition, UHV chamber for thermal desorption measurements and a sample transfer system between the chambers. It was found that a large amount of deuterium was accumulated in the lithium films. Deuterium thermal desorption spectra had two sharp peaks with maxima around 710 K and 850 K. Li D films kept in air at room temperature lost deuterium; no deuterium was detected in the films after three days in air. (C) 2014 Elsevier Ltd. All rights reserved.