scholarly journals Hydrogen Sorption Properties, Thermal Stability and Kinetics of Hydrogen Desorption From the Hydride Phase of The MgH2 of a Mechanical Alloys of Magnesium with Ti, Ni and Y

2020 ◽  
Vol 21 (1) ◽  
pp. 167-175
Author(s):  
O. G. Ershova ◽  
V. D. Dobrovolsky ◽  
Yu. M. Solonin
Keyword(s):  
Thermal Stability ◽  
Thermodynamic Stability ◽  
Hydrogen Desorption ◽  
Sorption Properties ◽  
Hydrogen Sorption ◽  
Hydride Phase ◽  
Phase Content ◽  
Stability Kinetics ◽  
Kinetics Of

The mechanical alloys-composite MАs (Mg +10 % wt.Ti + 5 % wt.Y and Mg +10 % wt.Ni + 5 % wt.Y) were synthesized. The phase content, microstructure, the thermal stability, kinetics of hydrogen desorption from the MgH2 hydride phase of the obtained MAs were studiedby using XRD, SEM, TDS methods. It has been established that the addition of Ti + Y and Ni + Y to magnesium leads to significant improvement in the kinetics of hydrogen desorption from the  MgH2 hydride phase, which is evidenced by a significant reduction (in 6 and 15 times)in the time of release of all hydrogen from MA1 and MA2, respectively. Due to, Ti, Ni,Y alloying, the decrease in the thermodynamic stability of MgH2 is not found.

scholarly journals The Influence of Complex Doping on Kinetics of Decomposition and Thermal Stability of Mg-Based Mechanical Alloys

2019 ◽  
Vol 20 (4) ◽  
pp. 406-415
Author(s):  
O.G. Ershova ◽  
V.D. Dobrovolsky ◽  
Yu.M. Solonin
Keyword(s):  
Thermal Stability ◽  
Thermal Desorption Spectroscopy ◽  
Hydrogen Desorption ◽  
Hydride Phase ◽  
Hydrogen Storage Alloys ◽  
Reactive Grinding ◽  
Kinetics Of ◽  
Reactive Mechanical Alloying ◽  
Thermal Stability Of ◽  
Complex Doping

Mechanical alloys (MАs) were synthesized by the method of reactive mechanical alloying. At a hydrogen pressure of 0.1 MPa, with the use of thermal desorption spectroscopy, the thermal stability, the kinetics of hydrogen desorption from the hydride phase MgH2 of the obtained MAs were studied. It has been established that the complex doping by of Fe, Si, Ti, leads to a significant improvement in the of hydrogen desorption from the hydride phase MgH2 of MA synthesized by the RMA. Hydrogen capacity CH of MА after reactive grinding for 20 h. was found to be equal to 5.7 % wt. Due to this alloying, the decrease in the thermodynamic stability of MgH2 is not established. The tested materials showed a high potential as hydrogen storage alloys especially for stationary application.

The Study of Hydrogen Sorption Properties of Mg17Al12La0.45

2011 ◽  
Vol 311-313 ◽  
pp. 1351-1356
Author(s):  
Li Juan Pang ◽  
Yun Gui Chen ◽  
Chao Ling Wu ◽  
Xue Feng Zhang ◽  
Gang Deng
Keyword(s):  
Ball Milling ◽  
Hydrogen Desorption ◽  
High Energy ◽  
Milling Process ◽  
High Energy Ball Milling ◽  
Sorption Properties ◽  
Hydrogen Sorption ◽  
Ball Milling Process ◽  
Energy Ball ◽  
Ball Milling Technique

Mg17Al12and rare earth improved Mg17Al12La0.45alloys were prepared by resistance melting method. The hydrogen sorption properties of the alloys with and without ball-milling process were investigated with the help of PCT measurements. The phase compositions of the experimental alloys were determined through powder X-Ray diffraction. It is found that the introduction of La and the high energy ball-milling technique could remarkably improve the hydrogen sorption capability of Mg17Al12. For Mg17Al12La0.45alloy, the hydrogen absorption starts at 473K and the hydridying rate increases at each temperature (573K, 523K, 473K) after high energy ball-milling process. The hydrogen desorption capacity of this alloy is 4wt% at 573K. XRD shows that there are two phases Mg17Al12and Al2La0.15Mg0.85after melting and Al2La0.15Mg0.85phase always exists during hydrogen sorption cycles of Mg17Al12La0.45.

scholarly journals The Effect of Hydride Phase on the Hydrogen Sorption Properties of the Non-Evaporable Ti0.3Zr0.2V0.5Getter Alloy

2005 ◽  
Vol 15 (5) ◽  
pp. 306-312
Author(s):  
Dongjin Lee ◽  
Jeshin Park ◽  
Changyoul Suh ◽  
Jaechun Lee ◽  
Wonbaek Kim
Keyword(s):  
Sorption Properties ◽  
Hydrogen Sorption ◽  
Hydride Phase

scholarly journals Effect of Al, Fe Addition on Thermodynamic Stability and Hydrogen Desorption KInetics from MgH2 Phase OF Mechanical Alloy

2015 ◽  
Vol 16 (3) ◽  
pp. 576-585 ◽  
Author(s):  
О.G. Еrshova ◽  
A.Yu. Koval ◽  
Yu.М. Solonin ◽  
V.D. Dobrovolsky
Keyword(s):  
Mechanical Alloy ◽  
Mechanochemical Synthesis ◽  
Thermodynamic Stability ◽  
Thermal Desorption Spectroscopy ◽  
Hydrogen Desorption ◽  
Hydrogen Atmosphere ◽  
Desorption Kinetics ◽  
Reactive Milling ◽  
Kinetics Of ◽  
Complex Doping

With the aim of lowering the temperature, improve the kinetics of the decomposition of stoichiometric hydride MgH2 was investigated the possibility of its complex doping Al, Fe using mechanochemical synthesis (RMS). The MA1 sample was derived by reactive milling  Mg + 10 wt% Al + 10 wt. % Fe powder mixture in the hydrogen atmosphere at pressure of 1.2 MPa in a reactor for 10 h. The formation (in conditions of mechanochemical synthesis) of hydride of solid solution of Al and Fe in magnesium Mg(Al,Fe)H2 was experimentally checked. Found that adding to magnesium Al & Fe leads to lower of thermodynamic stability and, consequently, to lower the temperature of the beginning of desorption of hydrogen to 250 0C at 0,1MPa H2 (compared to MgH2 without Al and Fe). After the first cycles of hydrogenation-dehydrogenation from gas phase MA, established by isobaric thermal desorption spectroscopy, the effect of lowering the temperature of the beginning desorbtion 315 0C (for non-alloy phase MgH2) to 250 0C was observed. Adding to magnesium aluminum with Fe significantly improves the kinetics of desorption of hydrogen from the hydride phase MgH2 mechanical alloy produced by RMS.

scholarly journals Thermal Stability Kinetics and Shelf Life Estimation of the Redox-Active Therapeutic and Mimic of Superoxide Dismutase Enzyme, Mn(III) meso-Tetrakis(N-ethylpyridinium-2-yl)porphyrin Chloride (MnTE-2-PyPCl5, BMX-010)

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Clarissa G. C. Maia ◽  
Bárbara C. R. de Araujo ◽  
Maria B. de Freitas-Marques ◽  
Israel F. da Costa ◽  
Maria Irene Yoshida ◽  
...  
Keyword(s):  
Neural Network ◽  
Thermal Stability ◽  
Artificial Neural Network ◽  
Superoxide Dismutase ◽  
Solid State ◽  
Shelf Life ◽  
Expiration Date ◽  
Redox Active ◽  
Stability Kinetics ◽  
Kinetics Of

Mn(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin chloride (MnTE-2-PyPCl5, BMX-010, and AEOL10113) is among the most studied superoxide dismutase (SOD) mimics and redox-active therapeutics, being currently tested as a drug candidate in a phase II clinical trial on atopic dermatitis and itch. The thermal stability of active pharmaceutical ingredients (API) is useful for estimating the expiration date and shelf life of pharmaceutical products under various storage and handling conditions. The thermal decomposition and kinetic parameters of MnTE-2-PyPCl5 were determined by thermogravimetry (TG) under nonisothermal and isothermal conditions. The first thermal degradation pathway affecting Mn-porphyrin structural integrity and, thus, activity and bioavailability was associated with loss of ethyl chloride via N-dealkylation reaction. The thermal stability kinetics of the N-dealkylation process leading to MnTE-2-PyPCl5 decomposition was investigated by using isoconversional models and artificial neural network. The new multilayer perceptron (MLP) artificial neural network approach allowed the simultaneous study of ten solid-state kinetic models and showed that MnTE-2-PyPCl5 degradation is better explained by a combination of various mechanisms, with major contributions from the contraction models R1 and R2. The calculated activation energy values from isothermal and nonisothermal data were about 90 kJ mol–1 on average and agreed with one another. According to the R1 modelling of the isothermal decomposition data, the estimated shelf life value for 10% decomposition ( t 90 % ) of MnTE-2-PyPCl5 at 25°C was approximately 17 years, which is consistent with the high solid-state stability of the compound. These results represent the first study on the solid-state decomposition kinetics of Mn(III) 2-N-alkylpyridylporphyrins, contributing to the development of this class of redox-active therapeutics and SOD mimics and providing supporting data to protocols on purification, handling, storage, formulation, expiration date, and general use of these compounds.

scholarly journals TiVZrNb Multi-Principal-Element Alloy: Synthesis Optimization, Structural, and Hydrogen Sorption Properties

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2799 ◽  
Author(s):  
Jorge Montero ◽  
Claudia Zlotea ◽  
Gustav Ek ◽  
Jean-Claude Crivello ◽  
Lætitia Laversenne ◽  
...  
Keyword(s):  
Ball Milling ◽  
Reversible Capacity ◽  
Hydrogen Desorption ◽  
Sorption Properties ◽  
Hydrogen Sorption ◽  
Principal Element ◽  
First Principle Calculation ◽  
Arc Melting ◽  
Bcc Structure ◽  
Mechanical And Microstructural Properties

While the overwhelming number of papers on multi-principal-element alloys (MPEAs) focus on the mechanical and microstructural properties, there has been growing interest in these alloys as solid-state hydrogen stores. We report here the synthesis optimization, the physicochemical and the hydrogen sorption properties of Ti0.325V0.275Zr0.125Nb0.275. This alloy was prepared by two methods, high temperature arc melting and ball milling under Ar, and crystallizes into a single-phase bcc structure. This MPEA shows a single transition from the initial bcc phase to a final bct dihydride and a maximum uptake of 1.7 H/M (2.5 wt%). Interestingly, the bct dihydride phase can be directly obtained by reactive ball milling under hydrogen pressure. The hydrogen desorption properties of the hydrides obtained by hydrogenation of the alloy prepared by arc melting or ball milling and by reactive ball milling have been compared. The best hydrogen sorption properties are shown by the material prepared by reactive ball milling. Despite a fading of the capacity for the first cycles, the reversible capacity of the latter material stabilizes around 2 wt%. To complement the experimental approach, a theoretical investigation combining a random distribution technique and first principle calculation was done to estimate the stability of the hydride.

Hydrogen Sorption Properties of the Complex Hydride Mg2FeH6 Consolidated by HPT

2010 ◽  
Vol 667-669 ◽  
pp. 1053-1058 ◽  
Author(s):  
Gisele Ferreira De Lima ◽  
Daniel Rodrigo Leiva ◽  
Tomaz Toshimi Ishikawa ◽  
Claudemiro Bolfarini ◽  
Claudio Shyinti Kiminami ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Activation Barrier ◽  
Hydrogen Desorption ◽  
Hydrogen Atmosphere ◽  
Sorption Properties ◽  
Hydrogen Sorption ◽  
Powder Form ◽  
Reactive Milling ◽  
Bulk Nanocrystalline

In the present work, we have processed 2Mg-Fe mixtures by reactive milling (RM) under hydrogen atmosphere to synthesize Mg2FeH6 phase in the powder form which were then systematically processed by High Pressure Torsion (HPT) to produce bulk samples. The bulk samples were characterized in terms of microstructural and structural analyses and of hydrogen desorption properties. The hydrogen sorption properties after HPT processing was evaluated in comparison with the Mg2FeH6 powder obtained by RM and with commercial MgH2. HPT processing of Mg2FeH6 can produce bulks with a high density of defects that drastically lower the activation barrier for hydrogen desorption. Therefore, the bulk nanocrystalline Mg2FeH6 samples show endothermic hydrogen decomposition peak at a temperature around 320°C. In addition, when compared with the Mg2FeH6 and MgH2 powders, the Mg2FeH6 HPT disks showed the same results presented by the Mg2FeH6 powders and certainly decreases the onset transition temperature by as much as 160°C when compared with the MgH2 powders.

Salts of (+)-deoxycholic acid with amines: structure, thermal stability, kinetics of salt formation, decomposition and chiral resolution

CrystEngComm ◽  
2013 ◽  
Vol 15 (5) ◽  
pp. 931-939 ◽  
Author(s):  
Ayesha Jacobs ◽  
Nikoletta B. Báthori ◽  
Luigi R. Nassimbeni ◽  
Baganetsi K. Sebogisi
Keyword(s):  
Thermal Stability ◽  
Deoxycholic Acid ◽  
Chiral Resolution ◽  
Salt Formation ◽  
Stability Kinetics ◽  
Kinetics Of
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