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The microwave ignition holds potential in the ignition of weapons due to its simple structure, non-contact property, and simultaneous ignitions of large area. However, the long ignition delay time of the current ignition agents cannot meet the microwave weaponry advancements. To address the issues, a microwave sensitive oxide-CuFe 2 O 4 (CUFO) which was firstly discovered to be easily ignited by microwaves compared many ferrites, was coupled with Ti nanoparticles (n-Ti) to form Ti/CUFO microwave ignition agents by electrostatic spray granulation. The characterization of microwave ignition, volumetric combustion, burning rate and DSC were used to determine its ignition delay time and the energy release properties. It indicates that the microwave sensitivity, maximum peak pressure and pressure pressurization rate of Ti/CUFO first increases and then decreases with the promoting content of n-Ti. The Ti/CUFO at Φ = 3.5 exhibits the lowest ignition delay time by 79.24 ms compared to the 98.7 ms of n-Ti, meanwhile, its maximum peak pressure and pressurization rate reach the highest by 338.54 kPa and 8.57 kPa/ms, respectively. The DSC results indicate that Ti/CUFO exhibits much lower reaction peak temperature by 320–335 °C compared to 488 °C of n-Ti, which suggests Ti-CUFO reaction maybe much easier be activated. The dielectric loss of n-Ti and CUFO under strong electric field transfer the energy of microwaves to heat, reaching to its reaction temperature. The XPS and XRD results of CUFO after microwave radiation disclosing the crystal transition, formation of divalent iron and oxygen vacancies, as well as the released bright light under microwave radiation, suggest the thermal breakdown mechanism of CUFO. When Ti/CUFO exposes into microwaves, CUFO generates oxygen vacancies due to heat loss and n-Ti is dielectric heated, followed by the generated oxygen reacting with n-Ti, improving the combustion performance of n-Ti. This result provides new insight for the designing of microwave ignition. [Display omitted] [ABSTRACT FROM AUTHOR]

The SiC/Si composites were prepared via selective laser sintering (SLS) combined with reactive melt infiltration (RMI) of liquid Si, using fine SiC particles with original particle sizes of 0.05, 0.8 and 5 μm. A novel electrostatic spraying combined with phase inversion (ES-PI) method was developed to assemble SiC particles into spherical powders (40–60 μm in diameter) before SLS, enabling SiC with excellent flowability. Commercial coarse SiC microparticles (∼40 μm) were also adopted to prepare the SiC/Si reference composite for comparison. Then the effects of the fine original particle sizes of SiC on the microstructures, as well as mechanical performance of composites were studied. Compared to commercial SiC microparticles, the ES-PI SiC microspheres show superior sphericity and fluidity but a relatively high porosity. However, the pores in ES-PI SiC microspheres, which are potentially detrimental to mechanical properties of composites, will be totally filled and eliminated in the SiC/Si composites after RMI. The mechanical performance of the SiC/Si composites printed using the fine nano (0.05 μm) and submicron (0.8 μm) original particles was effectively improved than the reference composite. When printed using the ES-PI SiC microspheres with 0.05 μm original particles, the flexural strength of the SiC/Si composite was enhanced by 25 %. This is attributed to the cracks deflection as well as the fracture mode transition from transgranular to intergranular rupture by the use of nano- or submicro-sized original SiC particles. This work provides an effective solution for preparing high strength SiC/Si composites with fine nano- or submirco particle sizes for space-based lightweight optical mirror using SLS. [ABSTRACT FROM AUTHOR]

In this study, a repeatable and environmentally friendly method was utilized to prepare a hydrophobic surface with photocatalytic features can be applied on large surfaces without the complexity of the chemical methods. In this regard, titanium dioxide nanoparticles and fluorinated ethylene propylene (FEP) resins were applied on an aluminum substrate using two methods of layer-by-layer and mixing through the electrostatic spraying approach. The prepared films were analyzed by scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Differential Reflectance Spectroscopy (DRS), energy-dispersive X-ray spectroscopy (EDS), and water contact angle (WCA) measurements. The photocatalytic activities were also explored by examining the degradation of oleic acid and four organic dyes under UV irradiation. This method led to formation of a hydrophobic photocatalytic surface with static contact angles above 130⁰. In the layer-by-layer method, the sample with one layer of titanium dioxide and three layers of FEP exhibited better hydrophobicity and photocatalytic performance. In the mixing method, better hydrophobicity and photocatalytic performance were observed in the one containing 10 wt% TiO 2. [ABSTRACT FROM AUTHOR]

In this research, a one-step and environmentally friendly method, free from the complexity of chemical techniques, was utilized to prepare a superhydrophobic surface that can be implemented on large scale. To this end, at first, silica nanoparticles were made hydrophobic through the silanization method, then got mixed with titanium dioxide nanoparticles and fluorinated ethylene propylene (FEP). Afterward, the combined materials were deposited on aluminum substrate using an electrostatic spraying method. In order to assess the fabricated surface, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and contact angle measurement are accomplished. In addition, the photocatalytic activity by the degradation of oleic acid and methylene blue (MB) upon UV exposure was studied. Results indicated formation of a superhydrophobic photocatalyst with contact angle over 150 °. This superhydrophobic surface containing nano silica content 12 wt% and TiO 2 20 wt% exhibited excellent photocatalytic activities in the organic materials degradation. The obtained photocatalyst surfaces also revealed proper stability in acidic (pH = 5) and alkaline (pH = 11) media. Moreover, a suitable stability was observed in the fouling medium with duration 10 h while no change in the static contact angle occurred. [ABSTRACT FROM AUTHOR]

In the present study, Blast Furnace Slag (BFS) waste was evaluated as a sustainable, cost-effective CaO, SiO 2 , Al 2 O 3 and MgO substitute for inorganic oxides for the production of frit, a raw material for glass ceramic production. Two different frits were prepared to compare a commercially available frit (F-STD) with frit produced using BFS waste (F-BFS). The samples were characterized by XRF, XRD, heating microscopy, dilatometry and TG-DTA to determine the chemical composition, phase formation and thermal properties. The frits were applied on steel using the electrostatic spray method and subsequently thermally treated at 830 °C for 4.5 min. The reference (GC-STD) and partially BFS-substituted glass ceramic (GC-BFS) coatings were examined by XRD, SEM-EDS and ICP-MS experiments. The main crystal phase for both samples was Ni-substituted fluorine mica (KLiNi 2 Si 4 O 10 F 2). GC-BFS was slightly more amorphous (70%) than GC-STD (69.1%), which was correlated with the thermal properties of the BFS waste. Likewise, ICP-MS analysis after a boiling citric acid test (ISO 28706-1: 2008) revealed that the GC-BFS had relatively higher chemical resistance. The total release from the reference sample (GC-STD) was 23.556 mg/L, whereas the total release from the sustainably produced sample (GC-BFS) was 21.451 mg/L, which was consistent with the XRD results. [ABSTRACT FROM AUTHOR]

Commercialization of thin film manufacturing is limited due to the long process time and fabrication cost. To solve these problems, the intense pulsed light sintering method was proposed in this paper. This novel sintering process using xenon lamp irradiation accomplished sintering in milliseconds in ambient air. For evaluation of the sintering effects, wide ranges of irradiation energy densities and substrate temperatures were investigated. The additional thermal energy from bottom-heating results in reducing the required photonic energy density. A flash light sintering process was applied to fabricate a lanthanum strontium manganese (La 0.8 Sr 0.2 Mn 1 O 3-δ) perovskite structure used in energy and memory devices. The La 0.8 Sr 0.2 Mn 1 O 3-δ thin film was coated by an electrostatic spray deposition (ESD) technique, using chemical deposition. This ESD technique is suitable for the flash light sintering process because a wet chemical method facilitates rapid and low-cost commercial fabrication. After the LSMO thin films were coated, the conventional thermal and flash light sintering processes were conducted, and the properties of the LSMO thin film were evaluated for remnant organics, electrical conductivity, crystallinity, and surface morphology. Flash light sintering delivers a complete sintering process in under 1 s, eliminating the frequent obstacles inherent in thermal sintering. [ABSTRACT FROM AUTHOR]

Mechanical resistance of Al 2 O 3 + TiO 2 nanocomposite ceramic coating deposited by electrostatic spray deposition method onto X10CrAlSi18 steel to thermal and slurry tests was investigated. The coating was produced from colloidal suspension of TiO 2 nanoparticles dispersed in 3 wt% solution of Al 2 (NO 3 ) 3 , as Al 2 O 3 precursor, in ethanol. TiO 2 nanoparticles of two sizes, 15 nm and 32 nm, were used in the experiments. After deposition, coatings were annealed at various temperatures, 300, 1000 and 1200 °C, and next exposed to cyclic thermal and slurry tests. Regardless of annealing temperature and the size of TiO 2 nanoparticles, the outer layer of all coatings was porous. The first five thermal cycles caused a rapid increase of aluminum content of the surface layer to 30–37 wt%, but further increase in the number of thermal cycles did not affect the aluminum content. The oxidation rate of coating-substrate system was lower during the thermal tests than during annealing. The oxidation rate was also lower for smaller TiO 2 particles (15 nm) forming the coating than for the larger ones (32 nm). The protective properties of Al 2 O 3 + TiO 2 coating against intense oxidation of substrate were lost at 1200 °C. Slurry tests showed that coatings annealed at 1000 °C had the best slurry resistance, but thermal tests had weakened this slurry resistance, mainly due to decreasing adhesion of the coating. [ABSTRACT FROM AUTHOR]

The objective of this work is to investigate the mechanical behavior of CGO-LSCF composite developed by electrostatic spray deposition as an oxygen electrode for Solid Oxide Fuel Cell and Solid Oxide Electrolysis Cell. The coating is characterized by a highly porous morphology designated coral microstructure. Its mechanical behavior was studied by scratch and ultramicroindentation tests and a model of material degradation under progressive compressive loading has been proposed. The coral's damage mechanism involves three regimes: at very low loads stresses are concentrated at the tips of individual corals that fracture and fill the spaces between corals (regime I); as load increases, generalized fracture of the corals occurs and the material starts compacting into an increasingly dense layer (regime II); finally, at the highest loads, the material behaves like an almost fully dense (regime III). As load increases during testing porosity decreases from about 60 to about 5 vol% in the compacted material. The transitions between regimes are associated to increases in the contact stress and the same damage mechanism is found during scratching and indentation. Hardness increases from about 2–100 MPa, while the Young's modulus varies in the range 1–18 GPa, as the porosity decreases. Calculations of the real contact pressure during loading allowed estimating a yield stress of 83 MPa that can be considered as a low limit for the materials fracture strength. [ABSTRACT FROM AUTHOR]

Anatase TiO 2 films with tunable nanoarchitectures were fabricated directly on conductive substrates using one-step electrostatic spray deposition (ESD). The morphology of TiO 2 films gradually evolved from one-dimensional (1D) rice-like to three-dimensional (3D) interconnected spiderweb-like architecture by only varying the flow rate of precursor solution with no need for templates or binders. The synergistic integration of the unique morphology and higher crystallite size imparted 3D-interconnected nanospiderwebs with remarkably enhanced photoconversion efficiency (6.52%) compared with commercial TiO 2 and other 1D nanoarchitectures. The self-powered ultraviolet (UV)-photodetector based on nanospiderwebs showed high photosensitivity (405300%), fast response and excellent photosensitivity linearity in a wide light intensity range. This self-powered device is a promising candidate for high-sensitivity and high-accuracy UV photodetectors. [ABSTRACT FROM AUTHOR]

Ferroelectric BaTiO 3 thin films were coated on titanium implants using an electrostatic spraying deposition method to combine the biocompatibility of a ceramic with the high mechanical strength of a metal. As-deposited films were annealed at 850 °C for 30 min in argon. Crystallinity, chemical structure, and surface morphology of the films were analyzed. Perovskite-type tetragonal BaTiO 3 films were obtained after post-annealing. Their ability to form calcium phosphate after poling treatments at above the Curie temperature was investigated with an in-vitro test in a simulated body fluid. Un-poled BaTiO 3 layer on titanium implant was partially covered with Na, Cl, and relatively small amounts of P and O ions, while the poled BaTiO 3 layer was wholly covered with calcium phosphate. [ABSTRACT FROM AUTHOR]

Abstract: This study aims to fabricate BaCe0.4Zr0.4Y0.2O3−δ (BCZY) thin film by electrostatic spray deposition (ESD) technique. Effects of ESD parameters, i.e. type of precursor, substrate temperature, applied voltage, nozzle-to-substrate distance and flow rate, were systematically studied and optimized for acquiring dense and crack-free as-deposited thin films. The half-cells of protonic ceramic fuel cell (PCFC) were subsequently fabricated by electro-depositing and co-sintering BCZY thin film electrolytes on the 60wt% NiO–40wt% BCZY anode substrates. Since dense BCZY films could not be attained on bare NiO–BCZY anode substrates, the anode functional layers (AFLs) with lower mass fractions of NiO:BCZY at 10:90, 30:70 and 50:50 was co-pressed on top of NiO–BCZY anode substrates. After co-sintering at 1500°C for 10h in air, the increasing BCZY film density was observed in the following order: AFL50:50

Abstract: Nanocrystalline transparent ZnO thin films, with different concentrations of niobium (Nb~0, 5, 10, 15 atoms per formula unit, at%), were successfully deposited by the electrostatic spray deposition method. The crystalline phase, surface morphology, surface roughness and photocatalytic properties of these Nb:ZnO thin films were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, and UV–visible spectroscopy, respectively. The Nb-doped films were tested for their photocatalytic abilities in aqueous solutions of methylene blue (MB) under UV illumination, where it showed that increasing Nb up to 10at%, with respect to ZnO, enhanced the photocatalytic activity. ZnO films doped with 10at% Nb demonstrated excellent photocatalytic activity, with degradation of MB achieved in fewer than 2h of UV irradiation. [Copyright &y& Elsevier]

Abstract: Graphene–ZnO (G–ZnO) composite thin films were produced using the electrostatic spray deposition technique (ESD). The effects of the concentration of graphene and annealing temperature on the structural and photocatalytic properties of the G–ZnO films were studied by X-ray diffraction, scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and UV–visible spectroscopy. We demonstrated that the G–ZnO films exhibit enhanced activities towards the photodegradation of methylene blue dye. A G–ZnO film with 0.1wt% graphene that was annealed at 300°C showed the highest photo-degradation activity. We found that the incorporation of graphene reduced electron–hole recombination in the ZnO film. [Copyright &y& Elsevier]

Ca2SnO4:Pr3+ phosphor coatings were prepared on silica glass substrates at a low temperature by electrostatic spray deposition using a soluble inorganic salt. The deposited films were pyrolyzed at 500°C for 1h in air. Final annealing was performed at 1000°C for 1h in air. Gels dried at 80°C for 24h were subjected to thermogravimetric analysis at 25–925°C to analyze the thermal decomposition process. Crystal structure and surface morphology of the films were examined by X-ray diffraction analysis and scanning electron microscopy. Photoluminescence spectra were measured by a fluorescent spectrophotometer. The phosphor film annealed at 1000°C showed orthorhombic structure and red emission at 626nm. [ABSTRACT FROM AUTHOR]

Abstract: Nano-sized gadolinium doped ceria (GDC) powders were successfully synthesized by aerosol flame deposition (AFD) with two different atomization methods; ultrasonic and electrostatic atomization. The effect of the atomization method on the size and morphology of GDC particles were investigated. It was observed that the diameter range of the GDC small primary particles synthesized by the ultrasonic atomization method was 10–50nm while with the electrostatic method was 5–25nm. In addition, the size of primary large particle found to be decreased from 200nm to 50nm with increasing electric field up to 15kV. The GDC powder synthesized by the electrostatic atomization exhibited reduced crystallite size, particle size, and similar electrical conductivity compared to GDC powder synthesized by ultrasonic atomization. This work demonstrated the benefits of the electrostatic atomization for producing smaller-sized GDC nanopowders for the application in intermediate temperature solid oxide fuel cells. [Copyright &y& Elsevier]