Sustainable sonoprocess for synthesizing γ-GaO/InSn core-shell submicron particles via acoustic emulsification and oxidation of molten EGaInSn at room temperature.

This study investigated the sustainable room-temperature synthesis of InSn/γ-GaO core-shell particles via an acoustic route using molten eutectic Ga-In-Sn alloy (EGaInSn). Sonication was used for the emulsification and oxidation steps. During the emulsification step, the sonication of molten EGaInSn in ethanol (EtOH) at 45 kHz facilitated the formation of the smallest EGaInSn particles (average diameter, D = 782 nm).

Sonochemical decomposition effects of nickelocene aiming for low-temperature and dispersant-free synthesis of nickel fine particle.

Sonochemical decomposition effects of nickelocene, which sublimates easily were investigated to synthesize dispersant-free nickel fine particles at low temperature. In a hydrazine monohydrate and 2-propanol mixed solvent, the reduction of nickelocene was promoted by ultrasound irradiation, and nickel fine particles were synthesized while precluding the sublimation of nickelocene. Unlike the common hydrazine reduction of nickel salts, which requires multiple-step reactions, nickelocene was reduced directly without forming intermediates.

Facile room temperature synthesis of size-controlled spherical silica from silicon metal via simple sonochemical process.

The waterglass or St o¨ ber method is commonly used to synthesize spherical colloidal silica; however, these methods have some disadvantages, such as complicated processes for the removal of sodium ions and expensive and energy-consuming raw materials such as tetraethoxysilane (TEOS). In this study, size-controlled spherical colloidal silica was synthesized from silicon metal at room temperature using an ultrasound process with hydrazine monohydrate as the solvent. Silicon metal dissolves easily in hydrazine monohydrate under ultrasound irradiation, and spherical colloidal silica can be synthesized by adding alcohol to this precursor solution.

Sonochemical decomposition of noble metal oxides and sonochemical alloying of gold-silver systems.

Recently, environmental problems, such as global warming, have become more severe; thus, there is a requirement to implement sustainable development goals in materials processing. In this study, we investigated a low-cost and environmentally-friendly sonochemical process for the synthesis of metal nanoparticles with large specific surface areas and catalysis effects. AuO hydrate and AgO were reduced to Au and Ag, respectively, at room temperature in a short time when irradiated with ultrasound in ethanol.

Sonochemical synthesis of supersaturated Ga-Al liquid-alloy fine particles and Al-doped γ-GaO nanoparticles by direct oxidation at near room temperature.

In this study, we investigated the fabrication of supersaturated gallium (Ga)-aluminum (Al) liquid alloy and Al-doped γ-GaO nanoparticles (NPs) at near room temperature (60 °C) using sonochemical and sonophysical effects. Supersaturated Ga-Al liquid alloy microparticles (D = 1.72 µm) were formed and stabilized at 60 °C by the thermal nonequilibrium field provided by sonochemical hot spots.

Decrease in the Crystallite Diameter of Solid Crystalline Magnetite around the Curie Temperature by Microwave Magnetic Fields Irradiation.

A decrease in the crystallite diameter of ferrites irradiated with microwaves has been considered as a non-thermal effect of so-called de-crystallization; however, its mechanism has not been elucidated. We hypothesized that a decrease in the crystallite diameter is caused by interaction between the ordered spins of ferrite and the magnetic field of microwaves. To verify this, we focused on magnetite with a Curie temperature of 585 °C.

Sonochemical effect and pore structure tuning of silica xerogel by ultrasonic irradiation of semi-solid hydrogel.

Silica xerogels were prepared by the sol-gel method under ultrasonic irradiation, using tetraethylorthosilicate (TEOS) as the starting material. Hexamethyldisiloxane (HMDSO) was used as the hydrophobizing agent. When preparing silica xerogel, it is necessary to perform aging and hydrophobization to suppress shrinkage during ambient pressure drying, however, such treatments are time-consuming.

Controlling oxygen coordination and valence of network forming cations.

Understanding the structure-property relationship of glass material is still challenging due to a lack of periodicity in disordered materials. Here, we report the properties and atomic structure of vanadium phosphate glasses characterized by reverse Monte Carlo modelling based on neutron/synchrotron X-ray diffraction and EXAFS data, supplemented by Raman and NMR spectroscopy. In vanadium-rich glass, the water durability, thermal stability and hardness improve as the amount of PO increases, and the network former of the glass changes from VO polyhedra to the interplay between VO polyhedra and PO tetrahedra.

Microwave Irradiation Process for Al-Sc Alloy Production.

Scandium is being explored as an alloying element for aluminium alloys, which are gaining importance as high-performance lightweight structural alloys in the transportation industry. Sc-rich ScAlN thin films show strong piezoelectricity and can be fabricated on a hard substrate for use as wideband surface acoustic wave filters in next-generation wireless mobile communication systems. However, the use of ScAlN thin films in microelectromechanical system devices is limited by the high cost of metallic Sc, which is due to the difficulty in smelting of this material.

Enhancement of Fixed-bed Flow Reactions under Microwave Irradiation by Local Heating at the Vicinal Contact Points of Catalyst Particles.

The formation of local high temperature regions, or so-called "hot spots", in heterogeneous reaction systems has been suggested as a critical factor in the enhancement of chemical reactions using microwave heating. In this paper, we report the generation of local high temperature regions between catalyst particles under microwave heating. First, we demonstrated that reaction rate of the dehydrogenation of 2-propanol over a magnetite catalyst was enhanced 17- (250 °C) to 38- (200 °C) fold when heated with microwave irradiation rather than an electrical furnace.

Formation of particle of bismuth-indium alloys and particle diameter by ultrasonic cavitation.

The miniaturization of electronic equipment requires fine bonding. Therefore, it is necessary to miniaturize the solder particles used for bonding different materials. Ultrasonic cavitation is a technique that uses ultrasonic irradiation to synthesize such microparticles.

Effect of Aspect Ratio on the Permittivity of Graphite Fiber in Microwave Heating.

Microwave (MW) heating has received attention as a new heating source for various industrial processes. Some materials are expected to be a more effective absorber of MW, and graphite is observed as a possible candidate for high-temperature application. We investigated the dependence of the aspect ratio of graphite fibers on both their heating behavior and permittivity under a 2.

In situ analysis of reaction kinetics of reduction promotion of NiMnO under microwave H-field irradiation.

Reaction kinetics during microwave H-field heating and electric furnace heating were investigated to verify the effect of rapid heating and the non-thermal microwave effect. This work is focused on the ferromagnetic material NiMnO, and the reduction reaction under rapid heating is investigated using an in situ analysis device. The results showed that the activation energy varied with the heating rate under microwave H-field irradiation, and it was the same as that in an electric furnace when the heating rate was the same.

Control of Magnetic Properties of NiMn₂O₄ by a Microwave Magnetic Field under Air.

NiMn₂O₄ prepared by conventional heating was irradiated with a microwave H-field using a single-mode cavity under air and magnetic properties of the microwave-irradiated material were investigated. X-ray diffraction and transmission electron microscopy demonstrated that the phase and microstructure are not affected by H-field irradiation. Measurements of the magnetization as a function of temperature revealed that the antiferromagnetic sublattice disappeared and electron spin resonance showed the existence of Mn, suggesting that Mn is partially reduced.

Preparation of platinum nanoparticles in heterogeneous solid-liquid system by ultrasound and microwave irradiation.

Pt nanoparticles and Pt/spherical carbon (SC) were prepared in a heterogeneous (PtO2/SC, water/ethanol) solid-liquid system without dispersant using ultrasound and microwave irradiation. The Pt nanoparticles and Pt/SC were characterized using X-ray diffraction (XRD), transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDX), and dynamic light scattering method for particle size determination. The average size of the Pt nanoparticles prepared by only ultrasound irradiation was smaller than that prepared by microwave irradiation.