Deuterium Permeation of Alumina Coating on 316L Prepared by Magnetron Sputtering

Theresearch and development of the structure materials that can resist the permeation of hydrogen and its isotopes is one of the important topics in the fusionreactor blanket.This paper describes the reduction of the effective deuterium permeation rate of 316L stainless steel obtained by the

Mechanochemistry and hydrogen storage properties of 2Li_(3)N+Mg mixture

The Li-Mg-N-H hydrogen storage system is a promising hydrogen storage material due to its moderate operation temperature,good reversibility,and relatively high capacity.In this work,the Li-Mg-N-H composite was directly synthesized by reactive ball milling(RBM) of Li3N and Mg powder mixture with a molar ratio of 2:1 under hydrogen pressure of 9 MPa.More than 8.8 wt%hydrogen was absorbed during the RBM process.The phases and structural evolution during the in situ hydrogenation process were analyzed by means of in situ solidgas absorption and ex situ X-ray diffraction(XRD) measurements.It is determined that the hydrogenation can be divided into two steps,leading to mainly the formation of a lithium magnesium imide phase and a poorly crystallized amide phase,respectively.The H-cycling properties of the as-milled composite were determined by temperature-programmed dehydrogenation(TPD) method in a closed system.The onset dehydrogenation temperature was detected at 125℃,and it can reversibly desorb 3.1 wt% hydrogen under a hydrogen back pressure of 0.2 MPa.The structural evolution during dehydrogenation was further investigated by in situ XRD measurement.It is found that Mg(NH_(2))_(2)phase disappears at about 200 ℃,and Li_(2)Mg_(2)N_(3)H_(3),LiNH_(2),and Li_(2)MgN_(2)H_(2)phases coexist at even 300 ℃,revealing that the dehydrogenation process is step-wised and only partial hydrogen can be desorbed.

Hydrogen storage properties of Li-Mg-N-B-H/ZrCoH_(3) composite with different ball-milling atmospheres

Li-Mg-N-B-H/ZrCoH_(3) composites were successfully synthesized by ball milling of the reactants under argon and hydrogen atmosphere,respectively.The composite synthesized by reactive ball milling(RBM)under hydrogen has the best hydrogen storage properties.It can desorb 3.71 wt%hydrogen in 60 min at 150℃under pressure of 0.1 MPa,and the dehydrogenation capacity reaches 4.59 wt%in 8 h.For the re-hydrogenation,5.27 wt%hydrogen was absorbed in only 10 min at 150℃under H_(2) pressure of 8 MPa.The phases of the as-milled and subsequently dehydrogenated and re-hydrogenated samples were determined by X-ray diffraction(XRD).The microstructures and elemental distributions were characterized by scanning electron microscope(SEM)and energy-dispersive spectrometer(EDS)measurements.It is shown that Mg is in situ hydrogenated and introduced homogeneous distribution of ZrCoH_(3) particles during the RBM process under hydrogen atmosphere.The activation energies for the composites were calculated by Kissinger method through differential scanning calorimetric(DSC)measurements for the dehydrogenation process with different heating rates.It is determined that the activation energy for the Li-Mg-N-B-H/ZrCoH_(3) composite synthesized by RBM under hydrogen is 79.9 kJ·mol^(-1),which is14 kJ·mol^(-1) lower than that for the sample without ZrCoH_(3) addition.The N-H bond energies were analyzed by infrared(IR)absorption spectrum,and the reasons for weakening of the N-H bond were further discussed.

Enhanced compactness and element distribution uniformity of Cu2ZnSnS4 thin film by increasing precursor S content

Cu2ZnSnS4 thin films were prepared by cosputtering with Cu(or Cu2S),ZnS and SnS2 targets in this study.S amount in the precursor of Cu2ZnSnS4 thin film was verified by using Cu or Cu2S target.The effect of S amount in the precursor on the microstructure and element distribution of Cu2ZnSnS4 thin film was discussed.It was found that S content is sufficient in the precursor thin film using Cu2 S instead of Cu target.The microstructure,composition homogeneity,and secondary phase formation of the Cu2ZnSnS4 thin film are seriously affected by S amount in the precursor thin film.Namely,sufficient S can improve the crystallization and orientation of the precursor thin film and enhance the compactness as well as composition homogeneity of the Cu2ZnSnS4 thin film after sulfurization.Moreover,the secondary phase formation in Cu2ZnSnS4 thin film can be greatly inhibited by increasing S content in the precursor thin film.

Preparation and characterisation of perovskite La0.8Sr0.2Ga0.83Mg0.17O2.815 electrolyte using a poly(vinyl alcohol)polymeric method

The perovskite La0.8Sr0.2Ga0.83Mg0.17O2.815 (LSGM) fuel cell electrolyte was prepared by a polymeric method using poly(vinyl alcohol) (PVA). The LSGM precursor powder was examined by thermogravimetric and differential thermal analysis (TG/DTA) and Fourier transform infrared (FTIR) spectroscopy. It was found that thermal decomposition of the LSGM precursor powder occurs in a number of different stages, and complete decomposition of the precursor is obtained at 1000 degrees C X-ray diffraction (XRD) showed that calcined powder contains three secondary phases, namely La4Ga2O9, LaSrGa3O7, and LaSrGaO4, even after calcination at 1100 degrees C Furthermore, the fraction of secondary phases decreases with increasing calcination temperature. Single phase perovskite LSGM pellets with a relative density of 97% were obtained after sintering at 1450 degrees C for 10 h. It was therefore shown that the powder prepared by the simple PVA method is fine, highly reactive, and sinterable. The electrical properties of LSGM pellets were characterised by impedance spectroscopy. The conductivity of the LSGM pellets sintered at 1450 degrees C for 10 h was 8.24x10(-2) S/cm at 800 degrees C.

Hydrogen storage properties of the CeH_2 doped Li-Mg-N-H/NaAlH_4 system

The mutual destabilization between complex hydrides and lithium amide has been comprehensively reported. In this paper, CeH2 doped Li-Mg-N-H/NaAlH4 composite was successfully synthesized by ball milling Li-Mg-N-H mixture and NaAlH4 in a molar ratio of 1：2. It was found that a total of 5 wt.% of hydrogen could be desorbed from the newly synthesized composite with a three-step reaction. Temperature-programmed-desorption （TPD） measurements showed that the composite ball milled for 10 min began to desorb hydrogen below 100 °C, which was about 75 °C lower than the pristine materials. XRD analysis revealed that NaAlH4 firstly reacted with LiH to yield Na2LiAlH6 and Al below 150 °C, then the newly developed Na2LiAlH6 reacted with Mg（NH2）2 to form NaH, Al, and Li2MgN2H2 in the temperature range of 180–250 °C. From 200 to 300 °C, the newly formed Al and Li2MgN2H2 reacted further to form Li2NH and some stable phase （AlN and Mg3N2）. The H-cycling properties of the composite were further investigated by a standard Sievert’s type apparatus at 150, 200 and 250 °C, respectively. Finally, the reversibility of the newly synthesized composite was discussed.