Articles
Publication Date: 2025
Jom (15431851)
The Sendust alloy (Fe85Si9.6Al5.4) was prepared by mechanical alloying, and the effects of milling time, speed, and the empty volume of the milling vial on its phase formation were investigated. Stoichiometric ratios of the raw materials, silicon, aluminum, and iron, were milled in stainless steel vials with volumes of 300 and 140 mL at different times and with different empty spaces, using a planetary high-energy ball mill. Additionally, the effect of milling speed on the phase formation of Sendust was examined, using a smaller vial. Phase identification was carried out using powder X-ray diffraction (XRD). According to the results, at 350 rpm, the desired phase was obtained in minimum times of 10 and 20 h in the 300 and 140 mL vials, respectively. The desired alloy was formed in 10 h milling at 450 rpm in the smaller vial. Thus, empty space in a vial and milling time are strongly interdependent, so, as empty space decreases, a longer milling time is required. However, at higher milling speeds, minimum required times are reduced in smaller empty spaces. © The Minerals, Metals & Materials Society 2025.
Publication Date: 2025
Energy and Fuels (08870624)39(24)pp. 11782-11792
Plasma catalysis for CO2 utilization technology shows considerable promise for advancement, with enhancing the synergistic relationship between plasma and catalysts being a key area of research challenge. However, current research focuses on the design of efficient catalyst formulations, but studies on metal-organic framework (MOF) screening and cold plasma methods have received less attention. Therefore, in this study, the hydrogenation of CO2 at ambient temperature and pressure was investigated using single-metal and bimetallic ZIF-67 as a MOF catalyst with the assistance of a dielectric barrier discharge (DBD) plasma reactor. The Co ZIF-67 and Ni Co ZIF-67 were synthesized and characterized by different analytical techniques. The synergistic effects between DBD plasma and these mono- and bimetal MOFs were investigated for the transformation protocol of CO2 to methanol. The flow rate of gas and input voltage as main parameters were screened. In this procedure, monometallic and bimetallic ZIF-67 showed 69.6 and 90.3% conversion with 84.1 and 98.1% selectivity of CH3OH production and 2.7 and 4.8 (mmol/kJ) energy efficiency under optimized conditions (flow rate: 60 mL/min; input voltage: 10 kV). Besides, the specific input energy of the transformation as a kinetic parameter was measured and showed linear behavior. The two catalysts can be reused up to six times without significant loss of their catalytic activities. © 2025 American Chemical Society.
Publication Date: 2024
Scientific Reports (20452322)14(1)
In this study, entanglement of composition, additive and/or sintering conditions and their effects on magnetic properties of soft ferrites, nickel zinc spinel ferrites (Ni1−xZnxFe2O4, x = 0.65 and 0.70) which were prepared via conventional solid-state reaction method investigated. Also an equiponderant calcined mixture of Bi2O3, CaO, CeO2, SiO2, Al2O3, Y2O3 and nanotitania was mixed thoroughly and used as a multi-compound calcined additive (MCCA). Calcined ferrite powders were crushed, dry and wet milled, dried, mixed with different amounts of MCCA (0.0, 0.5, 1.0, 1.5 and 2.0 wt%), formed in toroidal shapes and finally sintered at different temperatures, from 1150 up to 1360 °C for 3 h. X-ray diffraction assessment confirmed formation of the single phase cubic spinel structures. Initial permeability and Q-factor spectra of the toroids were obtained from 0.1 to 1000 kHz, using an LCR meter. The results show that initial permeability of each sample has a maximum and addition of MCCA to the ferrites leads to a marvelous increase in permeabilities. Additionally, MCCA decreases the optimum sintering temperature too. The optimum amounts of additive were 1.0 and 0.5 wt% for the x = 0.65 (μ′ = 492, Ts = 1280 °C) and x = 0.70 (μ′ = 478, Ts = 1320 °C), respectively. Permeability spectra illustrate that utility zone of the Ni0.35Zn0.65Fe2O4 and Ni0.3Zn0.7Fe2O4 are both less than 100 and 10 kHz, respectively. The results represent that there is a strong entanglement between composition, additive and/or sintering conditions. It can be concluded the MCCA added Ni0.35Zn0.65Fe2O4, is suitable for application in the switching power supplies. © The Author(s) 2024.
