Oxygen reduction reaction activity and structure of La-based perovskite oxides

1706 files in 35 folders, containing 388MB. Comprises plots, figures, and manuscripts. The data contains x-ray diffraction patterns and electrochemical data of lanthanum based perovskite oxides (e.g. 9 different perovskite compositions e.g. LaNiO₃, LaCoO₃, LaFeO₃, LaMnO₃, LaCrO₃, LaNi_0.5Co_0.5O₃ and LaNi_0.5Fe_0.5O₃, LaNi_0.5Mn_0.5O₃ and LaNi_0.5Cr_0.5O₃) characterized using rotating ring disk electrodes.

Dynamic strain-induced ferrite transformation during hot compression of low carbon Si-Mn steels

The dynamic strain-induced transformation (DSIT) of austenite to ferrite was investigated under different undercooling conditions using three low carbon Si-Mn steels. The undercooling of austenite (ΔT) was controlled by varying the cooling rate between austenitization and deformation temperatures. Uniform DSIT ferrite grains (∼2.3 μm) were produced at a relatively high deformation temperature above 840°C using a low carbon high Si steel (0.077C-0.97Mn-1.35Si, mass%) in connection with a larger ΔT. The critical conditions for DSIT were determined based on the flow stress-strain curves measured during hot compression tests. Influence of deformation temperature on DSIT of low carbon Si-added steel was also discussed.

Crystallographic features during martensitic transformation in Ni-Mn-Ga ferromagnetic shape memory alloys

The martensitic transformation crystallography in two Ni ₅₃Mn₂₅Ga₂₂ (at. %) ferromagnetic shape memory alloys (FSMAs) was investigated by means of misorientation calculation and pole figure analysis based on the orientation of the martensitic lamellae obtained from electron backscattered diffraction (EBSD) measurements. In the alloy that was first annealed at 1073K for 4h, and then cooled to 473K at ~4K/min and held for 30min, followed by cooling to room temperature at ~10K/min, there are only two kinds of differently orientated martensitic lamellae with a misorientation angle of ~82° distributed alternatively in each initial austenite grain. There is a compound twinning orientation relationship between the two lamellae. The prevalent orientation relationship between austenite and martensite is Kurdjumov-Sachs (K-S) relationship with (111)_A//(10I)_M, [1-10]_a//[11-1]_m. In the alloy that was annealed at 1173K for 4h followed by furnace cooling, nanoscale twins inside the martensitic lamellae were observed and the orientation relationships both between the nanotwins within one lamella and between the nanotwins in two neighboring lamellae were determined. The results presented in this paper will enrich the crystallographic data of the FSMAs and offer useful information for the development of novel FSMAs with optimal performances.

Preparation of size-selective Mn3O4 hexagonal nanoplates with superior electrochemical properties for pseudocapacitors

Porous Mn3O4 hexagonal nanoplates were synthesized through annealing the hydrohausmannite precursor obtained by a one-pot hydrothermal process and by precisely controlling the concentrations of potassium hydroxide and glucose. The effect of potassium hydroxide and glucose on the growth of hexagonal nanoplates was investigated, and a growth mechanism was also proposed. Due to its abundant pores, the pure Mn3O4-based electrode exhibits excellent cycling stability with 100% capacity retention after 5000 cycles. The asymmetric supercapacitor exhibited high performance with an energy density of 17.276 W h kg^-1 at a power density of 207.3 W kg^-1 in a wide potential window of 1.5 V.