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

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.

Reactive Grinding Synthesis of LaBO3 (B: Mn, Fe) Perovskite; Properties for Toluene Total Oxidation

LaBO3 (B: Mn, Fe) perovskites were synthesized using a three-step reactive grinding process followed by a calcination at 400 °C for 3 h. The three successive steps are: (i) solid state synthesis (SSR); (ii) high-energy ball milling (HEBM); (iii) low-energy ball milling (LEBM) in wet conditions. The impact of each step of the synthesis on the material characteristics was deeply investigated using physico-chemical techniques (X-ray diffraction (XRD), N2-physisorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS)) and the catalytic performances of the synthesized materials were evaluated for the toluene total oxidation reaction. Starting from single oxides, microcrystalline perovskite phase, exhibiting negligible surface areas, is obtained after the SSR step. The HEBM step leads to a drastic reduction of the mean crystal size down to ~20 nm, along with formation of dense aggregates. Due to this strong aggregation, surface area remains low, typically below 4 m2·g−1. In contrast, the second grinding step, namely LEBM, allows particle deagglomeration resulting in increasing the surface area up to 18.8 m2·g−1 for LaFeO3. Regardless of the perovskite composition, the performance toward toluene oxidation reaction increases at each step of the process: SSR < HEBM < LEBM.

MgH2–TiH2 mixture as an anode for lithium-ion batteries: synergic enhancement of the conversion electrode electrochemical performance

A 0.7MgH2 + 0.3TiH2 mixture was prepared by reactive grinding of Mg and Ti powders under hydrogen and tested as a conversion electrode for lithium-ion batteries.

Rheology of High Volume Sidoarjo Mud Mortar

Previous studies on Sidoarjo volcanic mud have been largely focusing on its use as low-volume cement replacement pozzolanic material and not as a high-volume cement replacement material. This study is intended to study the behaviour of fresh mortar incorporating Sidoarjo volcanic mud as cement replacement in high-volume i.e. 50%, 55% and 60%; and compares the results with the ones of high-volume fly ash mortar. Calcination and grinding were applied as pre-treatment for the mud to make it more reactive. Grinding time was varied into three different grinding time periods from two to eight hours, to vary the particle sizes of the calcined mud. The results show that the finer the particle size of the Sidoarjo volcanic mud, the bigger the flow of the fresh mortar. The flow of fresh mortar containing the Sidoarjo mud is lower compared to those of the ones with fly ash.