Effects of Length-to-Width Ratio on Magnetic and Microstructural Properties of Die-Upset Nd-Fe-B Magnets.

In this study, the effects of the length-to-width ratio on the magnetic and microstructural properties of die-upset Nd-Fe-B magnets were examined. A die-upset magnet with a uniform shape and no significant cracking was successfully developed. During the die-upset process, the applied pressure was not uniform across the magnet and varied depending on its shape and position.

Synergistic Effects in LaNiO Perovskites between Nickel and Iron Heterostructures for Improving Durability in Oxygen Evolution Reaction for AEMWE.

Perovskite materials that aren't stable during the oxygen evolution reaction (OER) are unsuitable for anion-exchange membrane water electrolyzers (AEMWE). But through manipulating their electronic structures, their performance can further increase. Among the first-row transition metals, nickel and iron are widely recognized as prominent electrocatalysts; thus, the researchers are looking into how combining them can improve the OER.

Antimicrobial Activity of Morphology-Controlled CuO Nanoparticles: Oxidation Stability under Humid and Thermal Conditions.

Metal oxides can be used as antimicrobial agents, especially since they can be fabricated into various forms such as films, masks, and filters. In particular, the durability of antimicrobial agents and the duration of their antimicrobial activity are important factors that determine their suitability for a specific purpose. These factors are related to the morphology and size of particles.

Effect of Various Acid Solutions on the CO Dissolution Rate, Morphology, and Particle Size of Precipitated Calcium Carbonate Synthesized Using Seashells.

In this study, the influence of acid solutions on the production of precipitated calcium carbonate (PCC) using seashells was investigated. In terms of the Ca dissolution efficiency and atmosphere for dissolving CO, the results indicate that HCl, HNO, CHCOOH, and HCOOH at 1.0 M were the most ideal among the acid solutions.

Design of High-Remanence Nd-Fe-B Hot-Pressed Magnets by Manipulating Coercivity of Hydrogenation-Disproportionation-Desorption-Recombination Treated Anisotropic Precursors.

We propose a method of manipulating the coercivity of anisotropic hydrogenation-disproportionation-desorption-recombination (HDDR) powders to fabricate high-remanence and fine-grained Nd-Fe-B magnets using only hot-pressing without a subsequent hot-deformation process. By reducing the Nd content of anisotropic HDDR precursors such that their coercivity (H) is lowered, the c-axis of each HDDR particle is well-aligned parallel to the direction of the applied magnetic field during the magnetic alignment step. This is because the magnetic repulsive force between adjacent particles, determined by their remanent magnetization, decreases as a result of the low coercivity of each particle.

Promoting electrocatalytic overall water splitting by sulfur incorporation into CoFe-(oxy)hydroxide.

The design and fabrication of highly cost-effective electrocatalysts with high activity, and stability to enhance the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been considered to be one of the most promising approaches toward overall water splitting. In this study, sulfur-incorporated cobalt-iron (oxy)hydroxide (S-(Co,Fe)OOH) nanosheets were directly grown on commercial iron foam galvanic corrosion and hydrothermal methods. The incorporation of sulfur into (Co,Fe)OOH results in superior catalytic performance and high stability in both the HER and OER conducted in 1 M KOH.

Electrocatalytic Properties of Pulse-Reverse Electrodeposited Nickel Phosphide for Hydrogen Evolution Reaction.

Nickel phosphide (Ni-P) films as a catalytic cathode for the hydrogen evolution reaction (HER) of a water splitting were fabricated by a pulse-reverse electrodeposition technique. The electrochemical behaviors for the electrodeposition of Ni-P were investigated by the characterization of peaks in a cyclic voltammogram. The composition of the electrodeposited Ni-P alloys was controlled by adjusting duty cycles of the pulse-reverse electrodeposition.

Cobalt-Iron-Phosphate Hydrogen Evolution Reaction Electrocatalyst for Solar-Driven Alkaline Seawater Electrolyzer.

Seawater splitting represents an inexpensive and attractive route for producing hydrogen, which does not require a desalination process. Highly active and durable electrocatalysts are required to sustain seawater splitting. Herein we report the phosphidation-based synthesis of a cobalt-iron-phosphate ((Co,Fe)PO) electrocatalyst for hydrogen evolution reaction (HER) toward alkaline seawater splitting.

Effect of Cathode Microstructure on Electrochemical Properties of Sodium Nickel-Iron Chloride Batteries.

Sodium metal chloride batteries have become a substantial focus area in the research on prospective alternatives for battery energy storage systems (BESSs) since they are more stable than lithium ion batteries. This study demonstrates the effects of the cathode microstructure on the electrochemical properties of sodium metal chloride cells. The cathode powder is manufactured in the form of granules composed of a metal active material and NaCl, and the ionic conductivity is attained by filling the interiors of the granules with a second electrolyte (NaAlCl).

Silane-treated BaTiO ceramic powders for multilayer ceramic capacitor with enhanced dielectric properties.

Silane/ceramic combination provides the composites with several advantages from the advancements of new ceramic composite materials with good thermal conductivity, high mechanical and dielectric properties have wide significant applications in electrical and electronic industries. In this study, to enhance the dispersibility of dielectric barium titanate (BaTiO) ceramic powder and additives for the fabrication of multilayer ceramic capacitors (MLCCs), surface treatment of the precursor of ceramic powder was performed using silane coupling agents. Dielectric ceramic sheets fabricated from ceramic powders that had been surface-treated with different amounts of N-[3-(trimethoxysilyl)propyl]aniline (TMSPA) which increased the surface gloss.

Effects of particle size and polymorph type of TiO on the properties of BaTiO nanopowder prepared by solid-state reaction.

Barium titanate (BaTiO) has attracted considerable attention as a perovskite ferroelectric ceramic material for electronic multilayer ceramic capacitors (MLCCs). Fine BaTiO nanopowders with a considerably high tetragonality directly influence the typical properties of nanopowders; however, their synthesis has remained challenging. In this study, we analyzed the effect of two different TiO powders with anatase and rutile phases in a solid-state reaction with barium carbonate (BaCO).

Effect of Copper Cobalt Oxide Composition on Oxygen Evolution Electrocatalysts for Anion Exchange Membrane Water Electrolysis.

Copper cobalt oxide nanoparticles (CCO NPs) were synthesized as an oxygen evolution electrocatalyst a simple co-precipitation method, with the composition being controlled by altering the precursor ratio to 1:1, 1:2, and 1:3 (Cu:Co) to investigate the effects of composition changes. The effect of the ratio of Cu/Co and the degree of oxidation during the co-precipitation and annealing steps on the crystal structure, morphology, and electrocatalytic properties of the produced CCO NPs were studied. The CCO electrode exhibited an outstanding performance and high stability owing to the suitable electrochemical kinetics, which was provided by the presence of sufficient Co as active sites for oxygen evolution and the uniform sizes of the NPs in the half cell.

Fabrication of TiB-Al1050 Composites with Improved Microstructural and Mechanical Properties by a Liquid Pressing Infiltration Process.

This study was conducted on titanium diboride (TiB) reinforced Al metal matrix composites (MMCs) with improved properties using a TiB and aluminum (Al) 1050 alloy. Al composites reinforced with fine TiB at volume ratios of more than 60% were successfully fabricated via the liquid pressing infiltration (LPI) process, which can be used to apply gas pressure at a high temperature. The microstructure of the TiB-Al composite fabricated at 1000 °C with pressurization of 10 bar for 1 h showed that molten Al effectively infiltrated into the high volume-fraction TiB preform due to the improved wettability and external gas pressurization.

Microstructural Evolution and Strengthening Mechanism of SiC/Al Composites Fabricated by a Liquid-Pressing Process and Heat Treatment.

Aluminum alloy (Al7075) composites reinforced with a high volume fraction of silicon carbide (SiC) were produced by a liquid-pressing process. The characterization of their microstructure showed that SiC particles corresponding to a volume fraction greater than 60% were uniformly distributed in the composite, and MgSi precipitates were present at the interface between the matrix and the reinforcement. A superior compressive strength (1130 MPa) was obtained by an effective load transfer to the hard ceramic particles.

Microstructure and Mechanical Properties of Functional Graded Ti-Al-Si-N-O Nanocomposite Films Deposited by Filtered Arc Ion Plating Technique.

Functional graded Ti-Al-Si-N-O nanocomposite films were deposited onto WC-Co substrate by a filtered arc ion plating system using TiAl and TiSi composite targets under N₂/Ar atmosphere. XRD and XPS analyses revealed that the synthesized Ti-Al-Si-N-O films were nanocomposite consisting of nanosized (Ti, Al, Si)N crystallites embedded in an amorphous Si₃N₄/SiO₂ matrix. The hardness of the Ti-Al-Si-N-O films exhibited the maximum hardness values of ~47 GPa at a Si content of ~5.

Carbon Nano Tube Supported Pd Catalyst: Effect of Support Textual Properties with Pre-Treatment Method of Pd Particle.

The aim of this work is to be compared the effect of supports textural properties with pre-treatment method on dispersion of Pd particle. The CNTs were functionalized by different concentration of acid in order to obtain materials with different chemical and physical properties. The characteristics of functionalized CNTs were investigated by FT-IR and Rama spectropy.

Synthesis of Glycerol Carbonate by Transesterification of Glycerol with Urea Over Zn/Al Mixed Oxide.

Reactions of glycerol carbonate using glycerol and urea have been carried out previously using ZnSO4 and ZnO catalysts, and high yields have been reported using ZnSO4 as catalyst. However, this salt is soluble in glycerol, and recycling of catalyst is difficult after the reaction. In this study, we prepared a mixed metal oxide catalyst using Zn and Al, and this catalyst consisted of a mixture of ZnO and ZnAl2O4.

Effective load transfer by a chromium carbide nanostructure in a multi-walled carbon nanotube/copper matrix composite.

Multi-walled carbon nanotube (MWCNT) reinforced copper (Cu) matrix composites, which exhibit chromium (Cr) carbide nanostructures at the MWCNT/Cu interface, were prepared through a carbide formation using CuCr alloy powder. The fully densified and oriented MWCNTs dispersed throughout the composites were prepared using spark plasma sintering (SPS) followed by hot extrusion. The tensile strengths of the MWCNT/CuCr composites increased with increasing MWCNTs content, while the tensile strength of MWCNT/Cu composite decreased from that of monolithic Cu.

Microfabrication and optical properties of highly ordered silver nanostructures.

Using thermal evaporation, we fabricated five uniform and regular arrays of Ag nanostructures with different shapes that were based on an anodized aluminum oxide template and analyzed their optical properties. Round-top-shaped structures are obtained readily, whereas to obtain needle-on-round-top-shaped and needle-shaped structures, control of the directionality of evaporation, pore size, length, temperature of the substrate, etc., was required.

Crystallization behavior of silicon quantum dots in a silicon nitride matrix.

Silicon quantum dot superlattice was fabricated by alternating deposition of silicon rich nitride (SRN) and Si3N4 layers using RF magnetron co-sputtering. Samples were then annealed at temperatures between 800 and 1,100 degrees C and characterized by grazing incident X-ray diffraction (GIXRD), transmission electron microscopy (TEM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). GIXRD and Raman analyses show that the formation of silicon quantum dots occurs with annealing above 1,100 degrees C for at least 60 minutes.

Investigation of bonding characteristics between Si quantum dots and a SiO2 matrix.

In order to understand and control the properties of Si quantum dot (QD) superlattice structures (SLS), it is necessary to investigate the bonding between the dots and their matrix and also the structures' crystallinities. In this study, a SiOx matrix system was investigated and analyzed for potential use as an all-silicon multi-junction solar cell. Si QD SLS were prepared by alternating deposition of Si rich SiOx (x = 0.

Advantages of using Ti-mesh type electrodes for flexible dye-sensitized solar cells.

We used Ti meshes for both the photoanodes and counter electrodes of dye-sensitized solar cells (DSSCs) to improve the flexibility and conductivity of the electrodes. These mesh type electrodes showed good transparency and high bendability when subjected to an external force. We demonstrated the advantages of cells using such electrodes compared to traditional transparent conducting oxide based electrodes and back side illuminated DSSCs, such as low sheet resistance, elevated photo-induced current and enhanced sunlight utilization.

Characterization of attractive interaction-driven carbon nanotube composites with Cd-based nanoparticles.

Multiwalled carbon nanotube (MWNT) composites with cadmium telluride (CdTe) or cadmium selenide (CdSe) nanoparticles were prepared via electrostatic interaction. The MWNTs were modified with carboxylic acid groups. Both the CdTe and CdSe nanoparticles were stabilized with 2-(dimethylamino) ethanethiol hydrochloride to develop positive charges on their surfaces in water.

Membrane growth of nanoporous silicates via the self-assembly monolayer.

The self-assembly monolayer (SAM) method was used for membrane fabrication, in which Si wafers were treated separately with N-trimethoxysilylpropyl-n,n,n-tri-n-butylammonium bromide (TMSP-TBA) and N-trimethoxysilylpropyl-n,n,n-trimethylammonium chloride (TMSP-TMA) to form monolayers on the Si surfaces. To grow silicate membranes on the organosilyl-treated Si wafers, a series of silicate sols were prepared with composites of tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as silicate sources, and tetrapropylammonium bromide (TPABr) was used as an organic template. Their microstructures were investigated in detail by comparing them using SEM and XRD.

The fabrication of TiO2 mesoporous thick films by employing a pre-embedded ZnO nanorods support.

TiO2 mesoporous films with a thickness more than 2 microm were synthesized through the evaporation-induced self-assembly approach. In order to prevent the formation of cracks due to the strain during the calcination, we employed the ZnO nanorod arrays as a pre-embedded support, which were obtained from an aqueous solution method. The spaces between ZnO nanorods were filled with TiO2 sol-gel by a dip-coater.