scholarly journals Epitaxial Growth of Ru and Pt on Pt(111) and Ru(0001), Respectively: A Combined AES and RHEED Study

2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
M. S. Zei
Keyword(s):  
Epitaxial Growth ◽  
Room Temperature ◽  
Lattice Mismatch ◽  
High Energy ◽  
Twin Plane ◽  
Surface Strain ◽  
High Energy Electron ◽  
Direction Parallel ◽  
Plane Normal ◽  
First Time

The epitaxial growth of Pt and Ru deposits by spontaneous, as well as by dynamic, electrodeposition onto Ru(0001) and Pt(111), respectively, have been studied by reflection high energy electron diffraction (RHEED) and Auger electron spectroscopy (AES). For the Pt deposit on Ru(0001), at submonolayer range, it preferably grows compressed commensurate bilayer thick islands on Ru(0001). This is the first time that RHEED observation of the onset of Pt twinning occurs in ca. 2-3 layer thick islands on Ru at room temperature, at which the surface strain due to the 2.5% lattice mismatch of Pt and Ru remains intact. For multilayer thick islands (>6 ML) ordered reflection twins (diameter of 3 nm) develop and are embedded in a (111) matrix with an incoherent (11-2) twin plane normal to Ru(0001) and aligned with their [−110] direction parallel to the [11-20] Ru(0001) substrate direction. For the Ru deposit on Pt(111), at 0.2 ML a strained () monoatomic layer is formed due to the 2.5% lattice mismatch of Ru and Pt. Increasing the coverage up to 0.64, the second Ru layer is found to relieve the strain in the first layer, giving rise to dislocations and Ru relaxes to its bulk lattice constant. Multilayers of Ru (>1 ML) result in (0001) nanocluster formation aligned with its [11-20] direction parallel to the [−110] Pt(111) substrate direction.

scholarly journals Mechanochemical Synthesis and Nitrogenation of the Nd1.1Fe10CoTi Alloy for Permanent Magnet

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3854
Author(s):  
Hugo Martínez Sánchez ◽  
George Hadjipanayis ◽  
Germán Antonio Pérez Alcázar ◽  
Ligia Edith Zamora Alfonso ◽  
Juan Sebastián Trujillo Hernández
Keyword(s):  
Mechanochemical Synthesis ◽  
Applied Field ◽  
Volume Fraction ◽  
Synthesis Method ◽  
High Energy ◽  
Direction Parallel ◽  
Best Value ◽  
Heat Treated ◽  
Bcc Phase ◽  
First Time

In this work, the mechanochemical synthesis method was used for the first time to produce powders of the nanocrystalline Nd1.1Fe10CoTi compound from Nd2O3, Fe2O3, Co and TiO2. High-energy-milled powders were heat treated at 1000 °C for 10 min to obtain the ThMn12-type structure. Volume fraction of the 1:12 phase was found to be as high as 95.7% with 4.3% of a bcc phase also present. The nitrogenation process of the sample was carried out at 350 °C during 3, 6, 9 and 12 h using a static pressure of 80 kPa of N2. The magnetic properties Mr, µ0Hc, and (BH)max were enhanced after nitrogenation, despite finding some residual nitrogen-free 1:12 phase. The magnetic values of a nitrogenated sample after 3 h were Mr = 75 Am2 kg–1, µ0Hc = 0.500 T and (BH)max = 58 kJ·m–3. Samples were aligned under an applied field of 2 T after washing and were measured in a direction parallel to the applied field. The best value of (BH)max~114 kJ·m–3 was obtained for 3 h and the highest µ0Hc = 0.518 T for 6 h nitrogenation. SEM characterization revealed that the particles have a mean particle size around 360 nm and a rounded shape.

scholarly journals A High Capacity, Room Temperature, Hybrid Flow Battery Consisting of Liquid Na-Cs Anode and Aqueous NaI Catholyte

Batteries ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 60 ◽  
Author(s):  
Caihong Liu ◽  
Leon Shaw
Keyword(s):  
Room Temperature ◽  
Electrochemical Impedance ◽  
Coulombic Efficiency ◽  
High Capacity ◽  
High Energy ◽  
Flow Battery ◽  
Membrane Interfaces ◽  
Number Of Cycles ◽  
Novel Concept ◽  
First Time

In this study, we have proposed a novel concept of hybrid flow batteries consisting of a molten Na-Cs anode and an aqueous NaI catholyte separated by a NaSICON membrane. A number of carbonaceous electrodes are studied using cyclic voltammetry (CV) for their potentials as the positive electrode of the aqueous NaI catholyte. The charge transfer impedance, interfacial impedance and NaSICON membrane impedance of the Na-Cs ‖ NaI hybrid flow battery are analyzed using electrochemical impedance spectroscopy. The performance of the Na-Cs ‖ NaI hybrid flow battery is evaluated through galvanostatic charge/discharge cycles. This study demonstrates, for the first time, the feasibility of the Na-Cs ‖ NaI hybrid flow battery and shows that the Na-Cs ‖ NaI hybrid flow battery has the potential to achieve the following properties simultaneously: (i) An aqueous NaI catholyte with good cycle stability, (ii) a durable and low impedance NaSICON membrane for a large number of cycles, (iii) stable interfaces at both anode/membrane and cathode/membrane interfaces, (iv) a molten Na-Cs anode capable of repeated Na plating and stripping, and (v) a flow battery with high Coulombic efficiency, high voltaic efficiency, and high energy efficiency.

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