In this study, (GaN)1-x(ZnO)x solid solution nanoparticles with a high zinc content are prepared by ultrasonic spray pyrolysis and subsequent nitridation. The structure and morphology of the samples are investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The characterization results show a phase transition from the Zn and Ga-based oxides (ZnO or ZnGa2O4) to a (GaN)1-x (ZnO)x solid solution under an NH3 atmosphere. The effect of the precursor solution concentration and nitridation temperature on the final products are systematically investigated to obtain (GaN)1-x(ZnO)x nanoparticles with a high Zn concentration. It is confirmed that the powder synthesized from the solution in which the ratio of Zn and Ga was set to 0.8:0.2, as the initial precursor composition was composed of about 0.8-mole fraction of Zn, similar to the initially set one, through nitriding treatment at 700oC. Besides, the synthesized nanoparticles exhibited the typical XRD pattern of (GaN)1-x(ZnO)x, and a strong absorption of visible light with a bandgap energy of approximately 2.78 eV, confirming their potential use as a hydrogen production photocatalyst.

The purpose of this study is to analyze the distribution characteristics of mist spray particle size by devising a rotary mist spraying device to develop the evaporative salt water desalination system. The rotary mist spraying device was consisted of a BLDC sirocco fan, a spinning fan, a fan fixed shaft and a salt water supply device etc. In this study we analyzed the characteristics of spray particle size and distribution according to the variation of sirocco fan surface roughness(Ra, μm), revolutions(rpm) and salt water flow rate(mL/min). When sirocco fan surface roughness( Ra) was in the range of 0.27~7.65 μm, the spray particle size was 0.117~1.360 μm. And then more than 90% of spray particles were found to be less than 0.50 μm. When sirocco fan surface roughness(Ra) was in the range of 12.70~22.84 μm, the spray particle size was 2.51~184.79 μm and more than 98% of spray particles were found to be less than 13.59 μm. To analyze the effect of fan rotation speed on the size and distribution of spray particles, when surface roughness Ra was fixed 0.27 μm and fan rotation speed and salt water flow rate was respectively changed at 3,800~5,600 rpm and 2.77~8.28 mL/min, spray particle size was 0.341~0.541 μm. And when salt water flow rate was 9.74 mL/min and fan rotation speed was 3,800~5,200 rpm, spray particle size was in the range of 29.29~341.46 μm and in case of 5,600 rpm more than 98.23% of spray particles were in the range of 2.51~13.59 μm.

In this study, ultrasonic spray pyrolysis combined with salt-assisted decomposition, a process that adds sodium nitrate (NaNO3) into a titanium precursor solution, is used to synthesize nanosized titanium dioxide (TiO2) particles. The added NaNO3 prevents the agglomeration of the primary nanoparticles in the pyrolysis process. The nanoparticles are obtained after a washing process, removing NaNO3 and NaF from the secondary particles, which consist of the salts and TiO2 nanoparticles. The effects of pyrolysis temperature on the size, crystallographic characteristics, and bandgap energy of the synthesized nanoparticles are systematically investigated. The synthesized TiO2 nanoparticles have a size of approximately 2–10 nm a bandgap energy of 3.1–3.25 eV, depending on the synthetic temperature. These differences in properties affect the photocatalytic activities of the synthesized TiO2 nanoparticles.

Current synthesis processes for titanium dioxide (TiO2) nanoparticles require expensive precursors or templates as well as complex steps and long reaction times. In addition, these processes produce highly agglomerated nanoparticles. In this study, we demonstrate a simple and continuous approach to synthesize TiO2 nanoparticles by a salt-assisted ultrasonic spray pyrolysis method. We also investigate the effect of salt content in a precursor solution on the morphology and size of synthesized products. The synthesized TiO2 nanoparticles are systematically characterized by X-ray diffraction, transmission electron micrograph, and UV-Vis spectroscopy. These nanoparticles appear to have a single anatase phase and a uniform particle-size distribution with an average particle size of approximately 10 nm. By extrapolating the plots of the transformed Kubelka-Munk function versus the absorbed light energy, we determine that the energy band gap of the synthesized TiO2 nanoparticles is 3.25 eV

The structural formation of inorganic nanoparticles dispersed in polymer matrices is a key technology for producing advanced nanocomposites with a unique combination of optical, electrical, and mechanical properties. Barium titanate (BaTiO3) nanoparticles are attractive for increasing the refractive index and dielectric constant of polymer nanocomposites. Current synthesis processes for BaTiO3 nanoparticles require expensive precursors or organic solvents, complicated steps, and long reaction times. In this study, we demonstrate a simple and continuous approach for synthesizing BaTiO3 nanoparticles based on a salt-assisted ultrasonic spray pyrolysis method. This process allows the synthesis of BaTiO3 nanoparticles with diameters of 20-50 nm and a highly crystalline tetragonal structure. The optical properties and photocatalytic activities of the nanoparticles show that they are suitable for use as fillers in various nanocomposites.

Inorganic phosphors based on ZrO2:Eu3+ nanoparticles were synthesized by a salt-assisted ultrasonic spray pyrolysis process that is suitable for industrially-scalable production because of its continuous nature and because it does not require expensive precursors, long reaction time, physical templates or surfactant. This facile process results in the formation of tiny, highly crystalline spherical nanoparticles without hard agglomeration. The powder X-ray diffraction patterns of the ZrO2:Eu3+ (1-20 mol%) confirmed the body centered tetragonal phase. The average particle size, estimated from the Scherrer equation and from TEM images, was found to be approximately 11 nm. Photoluminescence (PL) emission was recorded under 266 nm excitation and shows an intense emission peak at 607 nm, along with other emission peaks at 580, 592 and 632 nm which are indicated in red.

Fluorine-doped tin oxide (FTO) nanoparticles have been successfully synthesized using ultrasonic spray pyrolysis. The morphologies, crystal structures, chemical bonding states, and electrochemical properties of the nanoparticles are investigated. The FTO nanoparticles show uniform morphology and size distribution in the range of 6-10 nm. The FTO nanoparticles exhibit excellent electrochemical performance with high discharge specific capacity and good cycling stability (620mA h g−1 capacity retention up to 50 cycles), as well as excellent high-rate performance (250 mA h g−1 at 700mAg−1) compared to that of commercial SnO2. The improved electrochemical performance can be explained by two main effects. First, the excellent cycling stability with high discharge capacity is attributed to the nano-sized FTO particles, which are related to the increased electrochemical active area between the electrode and electrolyte. Second, the superb high-rate performance and the excellent cycling stability are ascribed to the increased electrical conductivity, which results from the introduction of fluorine doping in SnO2. This noble electrode structure can provide powerful potential anode materials for high-performance lithiumion batteries.

In this study, we fabricated Nd2Fe14B hard magnetic powders with various sizes via spray drying combined with reduction-diffusion process. Spray drying is widely used to produce nearly spherical particles that are relatively homogeneous. Thus, the precursor particles were prepared by spray drying using the aqueous solution containing Nd salts, Fe salts and boric acid with the target stoichiometric composition of Nd2Fe14B. The mean particle sizes of the spray-dried powders are in the range from one to seven micrometer, which are adjusted by controlling the concentra- tions of precursor solutions. After debinding the as-prepared precursor particles, ball milling was also conducted to con- trol the particle sizes of Nd-Fe-B oxide powders. The resulting particles with different sizes were subjected to subsequent treatments including hydrogen reduction, Ca reduction and washing for CaO removal. The size effect of Nd-Fe-B oxide particles on the formation of Nd2Fe14B phase and magnetic properties was investigated.

Hollow silica spheres were prepared by spray drying of precursor solution of colloidal silica. The precursor solution is composed of 10-20 nm colloidal silica dispersed in a water or ethanol-water mixture solvent with additives of tris hydroxymethyl aminomethane. The effect of pH and concentrations of the precursor and additives on the formation of hollow sphere particles was studied. The spray drying process parameters of the precursor feeding rate, inlet temperature, and gas flow rate are controlled to produce the hollow spherical silica. The mixed solvent of ethanol and water was preferred because it improved the hollowness of the spheres better than plain water did. It was possible to obtain hollow silica from high concentration of 14.3 wt% silica precursor with pH 3. The thermal conductivity and total solar reflectivity of the hollow silica sample was measured and compared with those values of other commercial insulating fillers of glass beads and TiO2 for applications of insulating paint, in which the glass beads are representative of the low thermal conductive fillers and the TiO2 is representative of infrared reflective fillers. The thermal conductivity of hollow silica was comparable to that of the glass beads and the total solar reflectivity was higher than that of TiO2.

Fecralloy is the promising materials for high temperature exhaust filtering system due to the excellent its oxidation resistance property. In this research, Fecralloy nanoparticles coated Fecralloy thin foil was prepared by a single nozzle electrospray system in order to increase surface area of Fecralloy foil. Fecralloy nanoparticles were fabricated by electrical wire explosion method in ethanol using Fecralloy wires as a source material. Electrospray modes with applied D.C voltages to Fecralloy colloidal solution were investigated to make a stable cone-jet mode. Coated layers with and without additional heat treatment were observed by FE-SEM (field emission-scanning electron microscope) and tape test for evaluating their adhesion to substrate were performed as well.

This study was focused on the optimization of low-pressure ultrasonic spraying process for synthesis of pure nanoparticles. As process variables, pressure in the reactor, precursor concentration, and reaction temperature were changed in order to control the chemical and microstructural properties of iron oxide nanoparticles including crystal phase, mean particle size and particle size distribution. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies revealed that pure nanoparticles with narrow particle size distribution of 5-15 nm were successfully synthesized from iron pentacarbonyl () in hexane under 30 mbar with precursor concentrations of 0.1M and 0.2M, at temperatures over . Also magnetic properties, coercivity () and saturation magnetization () were reported in terms of the microstructure of particles based on the results from vibration sampling magnetometer (VSM).

Flying and solidification behaviors of the particles manufactured by centrifugal atomization were investigated. Both models were solved by the explicit FDM. Flying calculation supported the experimental results that the finer particles flied shorter than coarser particles and that particles flied shorter for lower rotation velocity than for higher velocity. Cooling curve and dendrite arm spacing were predicted by use of heat transfer analysis.