Mechanochmical Synthesis of a Mg-Al-H Complex Hydrides

2012 ◽  
Vol 248 ◽  
pp. 274-279
Author(s):  
Xiao Dong Luo ◽  
Jing Zhang ◽  
Hao Liu
Keyword(s):  
Energy Density ◽  
Thermodynamic Calculation ◽  
Xrd Analysis ◽  
Magnesium Hydride ◽  
Reaction Process ◽  
Mill Time ◽  
Complex Hydrides ◽  
Al Powder

Magnesium hydride is considered as one of the most interesting alternatives for the reversible storage of hydrogen. In this study,The feasibility and reaction process of different materials（Mg and pretreated Al powders(mainly composed of Al and Ni)）were discussed and investigated by thermodynamic calculation. The effects of material proportioning, mill time, mill energy density were also investigated by XRD analysis and TG-DSC technique, and analyzed the essence mechanism. The results show that nano-sized MgH2 and Mg(AlH4)2 could be directly synthesized by pure Mg and pretreated Al powder, The product composite hydrides release 2.7wt% H2 through multi-step decompositions, of which the starting endothermic peaks are as low as 265°C.

Neue Synthesen mit Magnesiumhydrid Teil 2: Wege zu neuen komplexen Hydriden und zum Aluminiumwasserstoff / New Syntheses with M agnesium Hydride Part 2: Pathways to New Complex Hydrides and A luminium Hydride

1997 ◽  
Vol 52 (5) ◽  
pp. 629-634 ◽  
Author(s):  
Wilfried Knott
Keyword(s):  
Reducing Agents ◽  
Magnesium Hydride ◽  
New Class ◽  
Complex Hydrides

Abstract The reaction between autocatalytically prepared magnesium hydride (Tego® Magnan) and aluminium halides in ethers generates a new class of reducing agents, i.e. magnesium aluminium hydridohalides. By choosing dioxane-1,4 as solvent a route to an aluminium hydride dioxane complex is opened. The new reducing agents show outstanding selectivity especially in the field of organosilico-nes, combined with a maximum of safety in their application.

Reaction Process of Al-TiO2-C-Ti-Fe Multiphase System during Combustion Synthesis

2007 ◽  
Vol 336-338 ◽  
pp. 2340-2343 ◽  
Author(s):  
Song He Meng ◽  
Xing Hong Zhang ◽  
Wei Feng Zhang
Keyword(s):  
Intermetallic Compounds ◽  
Xrd Analysis ◽  
Reaction Process ◽  
Multiphase System ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Reaction Characteristics ◽  
Lower Temperature ◽  
Kinetics Of

The reaction process and kinetics of Al-TiO2-C-Ti-Fe system were investigated by differential scanning calorimetry (DSC) analysis, X-ray diffraction (XRD) analysis and scanning electron microscope (SEM). In order to obtain the information of reaction process for complicated system, the reaction characteristics of Al-TiO2, Al-TiO2-C and Al-TiO2-C-Ti systems are explored firstly. The results show that the reaction process varies with temperature in Al-TiO2-C-Ti-Fe system. At the lower temperature, the dominating reaction in Al-TiO2-C-Ti-Fe system is that between Al and Ti, Al and Fe, and so TiAlx, FeAlx, and Ti2Fe intermetallic compounds form. With the temperature increasing, the intermetallic compounds are decomposed. Then the decomposed Ti and Al react with C and TiO2 respectively and the stable TiC, Al2O3 and Fe three phases form in the final product.

scholarly journals Single Particle Combustion of Pre-Stressed Aluminum

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1737 ◽  
Author(s):  
Kevin J. Hill ◽  
Michelle L. Pantoya ◽  
Ephraim Washburn ◽  
Joseph Kalman
Keyword(s):  
Ignition Delay ◽  
Laser Heating ◽  
Xrd Analysis ◽  
Fuel Particle ◽  
X Ray Diffraction ◽  
Particle Combustion ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Order Of Magnitude ◽  
Al Powder

An approach for optimizing fuel particle reactivity involves the metallurgical process of pre-stressing. This study examined the effects of pre-stressing on aluminum (Al) particle ignition delay and burn times upon thermal ignition by laser heating. Pre-stressing was by annealing Al powder at 573 K and quenching ranged from slow (i.e., 200 K/min) identified as pre-stressed (PS) Al to fast (i.e., 900 K/min) identified as super quenched (SQ) Al. Synchrotron X-ray Diffraction (XRD) analysis quantified an order of magnitude which increased dilatational strain that resulted from PS Al and SQ Al compared to untreated (UN) Al powder. The results show PS Al particles exhibit reduced ignition delay times resulting from elevated strain that relaxes upon laser heating. SQ Al particles exhibit faster burn times resulting from delamination at the particle core-shell interface that reduces dilatational strain and promotes accelerated diffusion reactions. These results link the mechanical property of strain to reaction mechanisms associated with shell mechanics that explain ignition and burning behavior, and show pre-stressing has the potential to improve particle reactivity.

Effect of Calcination Temperature on the Breakdown Strength and Energy Density of CaCu3Ti4O12 Ceramic

2017 ◽  
Vol 888 ◽  
pp. 23-27 ◽  
Author(s):  
Mohd Fariz Ab Rahman ◽  
Mohamad Johari Abu ◽  
Rosyaini Afindi Zaman ◽  
Julie Juliewatty Mohamed ◽  
Mohd Fadzil Ain ◽  
...  
Keyword(s):  
Grain Size ◽  
Energy Density ◽  
Calcination Temperature ◽  
Single Phase ◽  
Breakdown Strength ◽  
Raw Materials ◽  
Sintered Sample ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Secondary Phases

The effect of calcination temperature on the breakdown strength and energy density of CaCu3Ti4O12 (CCTO) ceramics was studied. CCTO ceramics were prepared via solid state reaction method. The raw materials of CCTO were wet mixed for 24 hours and then dried overnight in oven. CCTO mixtures were calcined at three different temperature which is at 900°C, 930°C and 950°C for 12 hours. The calcined powders were compacted at 250 MPa and then were sintered at 1040°C for 10 hours. X-Ray Diffractometer (XRD) analysis showed the formation of CCTO phase and secondary phases of CuO and CaTiO3 for C900 calcined powders but single phase of CCTO was obtained by C930 and C950 calcined powders. Single phase of CCTO also were seen for all sintered samples. Observation on Scanning Electron Microscopy (SEM) micrographs showed large grain size was seen in C900 sintered sample and finer grain size was observed for C930 and C950 sintered samples. C900 sintered sample obtained highest dielectric constant (8617), highest breakdown strength (7.92 kV/cm), highest energy density (2.392 J/cm3).

Properties of AlN Powder Synthesized by Self-Propagating High Temperature Synthesis Process

2010 ◽  
Vol 434-435 ◽  
pp. 834-837 ◽  
Author(s):  
Jae Hwan Pee ◽  
Jong Chul Park ◽  
Kwang Taek Hwang ◽  
Soo Ryong Kim ◽  
Woo Seok Cho
Keyword(s):  
High Temperature ◽  
Xrd Analysis ◽  
Nitrogen Atmosphere ◽  
Synthesis Process ◽  
Microstructure Development ◽  
Temperature Synthesis ◽  
Powder Mixtures ◽  
Residual Oxygen ◽  
High Temperature Synthesis ◽  
Al Powder

The synthesis of AlN via self-propagating high-temperature synthesis (SHS) was attempted, using various ratio of Al powder mixed with AlN powder as diluents. Al and AlN powder mixtures with various weight ratios were ignited a nitrogen atmosphere with various amounts of carbon as additives. High crystalline AlN by SHS were successfully synthesized. The microstructure development during the reaction and the influence of these additives were determined by SEM and XRD analysis. A mechanism for the formation of high purity AlN with a very low content of residual oxygen (<0.8wt %) was proposed.

Hydrogen Permeation Performance and Chemical Stability of Ni-La1.95Ca0.05Ce2O7-δ in an H2S-Containing Atmosphere

2009 ◽  
Vol 79-82 ◽  
pp. 1695-1698 ◽  
Author(s):  
Li Tao Yao ◽  
Shu Min Fang ◽  
Wei Liu
Keyword(s):  
Phase Composition ◽  
Chemical Stability ◽  
Thermodynamic Calculation ◽  
Hydrogen Permeation ◽  
Xrd Analysis ◽  
Permeation Flux

In this paper, the hydrogen permeation performance of Ni-La1.95Ca0.05Ce2O7-δ (Ni-LDC) was measured in an H2S-containing atmosphere at 1073K. In 75, 150 and 300 ppm H2S, the hydrogen permeation flux decreased by about 5%, 15%, 30% respectively. XRD analysis revealed that sample showed a little formation of Ni3S2, La2O3, LDC, Ni, Ce2O2S. Based on the analysis of the microstructure and phase composition, and results of thermodynamic calculation, we suggested that the reaction between H2S and CeO2 is main cause of hydrogen permeation performance of the Ni-La1.95Ca0.05Ce2O7-δ cermet lossing.

scholarly journals Effect of CeO2 on Microstructure and Synthesis Mechanism of Al-Ti-C Alloy

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2508 ◽  
Author(s):  
Wanwu Ding ◽  
Taili Chen ◽  
Xiaoyan Zhao ◽  
Chen Xu ◽  
Xingchang Tang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Kinetic Model ◽  
Thermodynamic Calculation ◽  
Raw Materials ◽  
Graphite Powder ◽  
Microstructure Analysis ◽  
Synthesis Mechanism ◽  
Experiment Method ◽  
Al Powder ◽  
Ti Powder

The effects of CeO2 on the microstructure and synthesis mechanism of Al-Ti-C alloy were investigated by quenching experiment method, while using Al powder, Ti powder, graphite powder, and CeO2 powder as main raw materials. The results showed that the addition of CeO2 was favorable for promoting the formation of TiC particles in Al-Ti-C systems. With CeO2 contents increasing, the distribution of TiC particles were more homogeneous, and the rare earth phase Ti2Al20Ce was formed. CeO2 had little effect on the synthesis of Al3Ti particles in Al-Ti-C systems, but had a significant effect on the synthesis of TiC particles. In the Al-Ti-C system, TiC is mainly formed by the reaction of dissolved [Ti] and solid C in the melt. While in the Al-Ti-C-Ce system, CeO2 reacts with C and O2 to form CeC2 firstly, and then CeC2 reacts with dissolved [Ti] to form TiC. Based on thermodynamic calculation and microstructure analysis in the process of reaction, a macroscopic kinetic model of Al-Ti-C-Ce system reactions was proposed in this paper.

scholarly journals Effect of Laser Energy Density, Internal Porosity and Heat Treatment on Mechanical Behavior of Biomedical Ti6Al4V Alloy Obtained with DMLS Technology

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2331 ◽  
Author(s):  
Żaneta Anna Mierzejewska
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Energy Density ◽  
Laser Energy ◽  
Xrd Analysis ◽  
Laser Energy Density ◽  
Simultaneous Increase ◽  
Direct Metal Laser Sintering ◽  
X Ray Diffraction ◽  
Elongation At Break

The purpose of this paper was to determine the influence of selected parameters of Direct Metal Laser Sintering and various heat treatment temperatures on the mechanical properties of Ti6Al4V samples oriented vertically (V, ZX) and horizontally (H, XZ). The performed micro-CT scans of as-build samples revealed that the change in laser energy density significantly influences the change in porosity of the material, which the parameters (130–210 W; 300–1300 mm/s), from 9.31% (130 W, 1300 mm/s) to 0.16% (190 W, 500 mm/s) are given. The mechanical properties, ultimate tensile strength (UTS, Rm) and yield strength (YS, Re) of the DMLS as-build samples, were higher than the ASTM F 1472 standard suggestion (UTS = 1100.13 ± 126.17 MPa, YS = 1065.46 ± 127.91 MPa), and simultaneously, the elongation at break was lower than required for biomedical implants (A = 4.23 ± 1.24%). The low ductility and high UTS were caused by a specific microstructure made of α’ martensite and columnar prior β grains. X-Ray Diffraction (XRD) analysis revealed that heat treatment at 850 °C for 2 h caused the change of the microstructure intothe α + β combination, affecting the change of strength parameters—a reduction of UTS and YS with the simultaneous increase in elongation (A). Thus, properties similar to those indicated by the standard were obtained (UTS = 908.63 ± 119.49 MPa, YS = 795.9 ± 159.32 MPa, A = 8.72 ± 2.51%), while the porosity remained almost unchanged. Moreover, the heat treatment at 850 °C resulted in the disappearance of anisotropic material properties caused by the layered structure (UTSZX = 908.36 ± 122.79 MPa, UTSXZ = 908.97 ± 118.198 MPa, YSZX = 807.83 ± 124.05 MPa, YSXZ = 810.56 ± 124.05 MPa, AZX = 8.75 ± 2.65%, and AXZ = 8.68 ± 2.41%).

scholarly journals Electrical power generation with PEM FC using hydrogen supply through Mg-Ni reaction with water

Energetika ◽  
2016 ◽  
Vol 62 (1-2) ◽  
Author(s):  
Dalius Girdzevičius ◽  
Darius Milčius
Keyword(s):  
Power Generation ◽  
Fuel Cell ◽  
Hydrogen Production ◽  
Hydrogen Generation ◽  
Hydrogen Plasma ◽  
Electrical Power ◽  
Clean Energy ◽  
Xrd Analysis ◽  
Magnesium Hydride ◽  
Reaction With Water

Hydrogen is considered an energy vector of the future because of its potential use for clean energy generation. Portable electronic devices can be powered when hydrogen is supplied to fuel cells. In order to avoid massive equipment for hydrogen storage, direct hydrogen production can be achieved on-site during the reaction between metals/metal alloys/metal hydrides and water. Magnesium hydride offers great perspective for widespread applications as its weight yield of hydrogen reaches 6.4% according to the reaction with water and it can even increase to 15.2% if water produced in the fuel cell is used in the reaction again. In the  present work, Mg powder with the  content of Ni was synthesized under low temperature hydrogen plasma conditions changing the DC magnetron current from 0.5 to 1 A. As pure Mg powder was immersed into hydrogen plasma, the simultaneous hydrogenation process was ensured. Nickel was chosen as a catalyst capable to influence the growth of hydride. The process of electric power generation was investigated when reaction between modified Mg powder and water was applied to laboratory-built equipment consisting of a reactor for hydrogen production, gas dryer before H2 introduction to the  fuel cell, fuel cell, load and energy meter. Solutions of acetic acid and sodium chloride were used as promoters during powder-water reactions. The characterisation of predicted magnesium hydride powder was done using scanning electron microscopy, electron dispersive spectroscopy and X-ray diffraction. XRD analysis showed only Mg, MgO and Ni peaks indicating that hydrogen generation during powder-water reaction was evoked because of microgalvanic corrosion at Mg-Ni intersections.

Identification of acid-insoluble filter-plugging compounds and optimal acid-washing procedures for tubular backpulse pressure filters

TAPPI Journal ◽  
2011 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
KEVIN TAYLOR ◽  
RICH ADDERLY ◽  
GAVIN BAXTER
Keyword(s):  
Calcium Sulfate ◽  
Membrane Filter ◽  
Sulfamic Acid ◽  
Xrd Analysis ◽  
Metal Sulfides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gypsum Formation ◽  
Acid Washing ◽  
Hydrolysis Of

Over time, performance of tubular backpulse pressure filters in kraft mills deteriorates, even with regular acid washing. Unscheduled filter replacement due to filter plugging results in significant costs and may result in mill downtime. We identified acid-insoluble filter-plugging materials by scanning electron microscope/energy-dispersion X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis in both polypropylene and Gore-Tex™ membrane filter socks. The major filter-plugging components were calcium sulfate (gypsum), calcium phosphate (hydroxylapatite), aluminosilicate clays, metal sulfides, and carbon. We carried out detailed sample analysis of both the standard acid-washing procedure and a modified procedure. Filter plugging by gypsum and metal sulfides appeared to occur because of the acid-washing procedure. Gypsum formation on the filter resulted from significant hydrolysis of sulfamic acid solution at temperatures greater than 130°F. Modification of the acid-washing procedure greatly reduced the amount of gypsum and addition of a surfactant to the acid reduced wash time and mobilized some of the carbon from the filter. With surfactant, acid washing was 95% complete after 40 min.

Sign in / Sign up

Export Citation Format

Share Document