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In this paper, nickel nitrate, copper nitrate, cobalt nitrate, ferric nitrate were used as raw materials, citric acid was used as a complexing agent, and chromium nitrate was used as a modifier to synthesize Ni 0. 2 Cu 0. 2 Co 0. 6 Cr x Fe 2 − x O 4 by sol–gel method. The sample was characterized. X-ray diffraction (XRD) data on the sample showed that the particle size of the sample was 52.14–54.88 nm. The lattice constant varied from 8.3569 Å to 8.3758 Å. The data of Fourier infrared showed that the sample did not change with the structure of the doped sample of Cr ion and remained as the spinel type. It can be seen by SEM that the sample is irregularly spherical. Due to the doping of chromium ions, it appears agglomerated. Analysis of the elements of the sample by EDAX revealed that the sample contained Ni, Cu, Co, Fe, O and a peak corresponding to the Cr element was found in the sample having crion content of 0.025, 0.050, 0.075 and 0.100. The magnetic properties of the samples were characterized using VSM. The data are processed to obtain magnetic parameters such as saturation magnetization and coercivity. [ABSTRACT FROM AUTHOR]

Bismuth ferrite (BiFeO 3) nanorods have been prepared from 2-methoyethanol (2-MOE)-assisted sol–gel technique. Structure, dielectric, and magnetic properties of BiFeO3 nanorods are briefly discussed in this paper. Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results suggest that the BiFeO3 peaks calcined at 500∘C exhibit a distorted rhombohedral perovskite structure with the absence of other secondary phases like Bi2Fe4O9. Meanwhile, the BiFeO3 showed excellent photoluminescence (PL) behavior due to the transmission of electrons from conduction band to the valence band. Ferroelectric hysteresis loop of BiFeO3 shows an increase of coercivity from 5.5–6 μ C/cm2 in a frequency range of 6–12 kHz. The magnetization measurement resulted in a well-saturated ferromagnetic behavior, and in addition, the temperature-dependent magnetization was discussed for BiFeO3 nanorod using superconducting quantum interference device (SQUID) method. The zero-field-cooled (ZFC) and field-cooled (FC) curves reveal spin-glass effect owing to size effects, spin exchange, and anisotropy of material assembly. [ABSTRACT FROM AUTHOR]

In this paper, low temperature, economical sol–gel combustion method was adopted to synthesize wollastonite ceramic. Calcium nitrate tetrahydrate and tetraethyl orthosilicate were taken as source for Ca and Si, while citric acid and nitric acid were used as chelating/combustion agents. The yielded powder calcined at 600 ∘ C for 4 h was characterized by FTIR, XRD and SEM techniques. Results showed that the citrate combustion method was the most efficient method to prepare wollastonite at low temperature. Moreover, in vitro bioactivity test performed in simulated body fluid (SBF) showed good bioactivity of synthesized wollastonite ceramics. [ABSTRACT FROM AUTHOR]

The multifunctional textiles are interesting areas to be researched on. In this paper, the effect of the fiber nanocoating on the wrinkle recovery, air permeability and anti-Ultraviolet (UV) property of different woven fabrics using sol-gel method has been studied. The sol-gel method has various advantages over other methods. Along with these properties, no change in visual appearance has also been discussed in this paper. The dispersion of nanoparticles of titanium was obtained into silica sol. The characterization of nanocoating was done using Field emission scanning electron micrograph (FESEM) and Fourier transform infrared spectroscopy (FTIR) studies. The fabric wrinkle recovery properties, air permeability and anti-UV performance were analyzed using three different immersion timings into the nanosol. The results revealed that both wrinkle recovery properties and anti-UV performance have increased with respect to immersing time of the nanocoating although a slight decrease in air permeability and whiteness index of the fabric was also observed. [ABSTRACT FROM AUTHOR]

This paper contains the results of the structural and spectroscopic characterizations of undoped and Cadmium-doped cobalt oxide thin films with different Co/Cd molar ratios (3%, 5%, 7% and 9%). The nanosized undoped and cadmium-doped Co3O4 thin layers were prepared using sol–gel process and deposited on glass substrates by dip coating. The changes caused by the incorporation of cadmium at different levels of doping have been highlighted by the techniques UV–Visible (UV–Vis) spectroscopy, Infrared (IR) spectroscopy, X-ray diffraction (XRD) measurements, SEM coupled EDX and impedance spectroscopy. From the UV–Vis spectroscopy analysis, it was found that all the films are two direct bandgap energies. The optical transmittance and the bandgap energy decrease with increase in Cd concentration. The XRD spectra confirm the films were polycrystalline with a cubic spinel structure. The results of the impedance spectroscopy show that the equivalent circuit of the synthesized samples is an RC parallel circuit. [ABSTRACT FROM AUTHOR]

In this paper, anisotropic SiO2 with different morphologies were synthesized through an emulsion-based one-pot method by adding various silane coupling agents. Silane coupling agents affected the growth of silica nanostructures at the oil/water interfaces. Robust super-repellent film that showed great durability under different harsh conditions were obtained by bonding the self-assembled anisotropic silica nanostructures (ASN) film to substrate by the commercial acrylic adhesive. The film switched from superhydrophobic (157.1 to superhydrophilic (0 after being heat-treated at 500C. Further, silane treatment with addition of acid reduced the time of modification. Meanwhile, silane grafting density was improved and superhydrophobicity of calcinated ASN films was regenerated. Anisotropic silica nanostructures with different morphologies were synthesized by the co-growth of silane coupling agent. Modified silica particles with high aspect ratio were assembled to prepare super-repellent film. Robust super-repellent film that showed great durability under different harsh conditions was obtained by bonding the self-assembled anisotropic silica nanostructure (ASN) films to substrate by commercial adhesive. [ABSTRACT FROM AUTHOR]

Li-Co nanoferrites (LiCoFeO4) with x = 0.00, 0.03, 0.06, 0.09, and 0.12, were synthesized by chemical sol-gel method. Two different sintering techniques viz. conventional technique (CT) and microwave technique (MT) were employed to heat treat the synthesized samples with an aim to study the effect of sintering technique on the properties of the nanoferrites. Structural and microstructural properties of the samples were investigated using XRD and scanning electron microscopy (SEM) technique, respectively. The variation of room temperature dielectric constant and dielectric loss were measured as a function of frequency in the range 100 Hz-1 MHz and the normal dispersive behavior was observed. Magnetic properties were investigated using Vibrating Sample Magnetometer (VSM), while Soohoo's method was used to measure Curie temperature. The results obtained have been discussed in the paper. [ABSTRACT FROM AUTHOR]

In the present paper, the influences of different double layer on wear and scratch performances of commercially pure Titanium (CP-Ti) were investigated. TiO2/SiO2 and SiO2/TiO2 double layer coatings were deposited on CP-Ti by sol-gel dip coating process and calcined at 750C. The phase structure, cross-sectional morphology, composition, wear track morphologies, adhesion properties, hardness and roughness of uncoated and coated samples were characterized with X-ray diffraction, scanning electron microscopy (SEM), nano-indentation technique, scratch tester and 3D profilometer. Also, the tribological performances of all samples were investigated by a pin-on-disc tribo-tester against Al2O3 ball. Results showed that hardness, elastic modulus and adhesion resistance of double layer coated samples were higher than untreated CP-Ti. It was found that these properties of TiO2/SiO2 double layer coatings have higher than SiO2/TiO2 double layer coating. Additionally, the lowest friction coefficient and wear rates were obtained from TiO2/SiO2 double layer coatings. Therefore, it was seen that phase structure, hardness and film adhesion are important factors on the tribological properties of double layer coatings. [ABSTRACT FROM AUTHOR]

In this paper, potassium sodium niobate (KNN) nanopowders were successfully obtained by sol-gel combustion method. According to thermogravimetric analysis (TGA) results, the produced xerogel was calcined at 500C, 600C, and 700C to obtain KNN powders. The structural and optical properties of the prepared powders were studied using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, transmission electron microscopy (TEM), and UV-vis spectroscopy. The XRD patterns indicated formation of orthorhombic KNN samples. The Scherrer formula and size-strain plot (SSP) method were employed to calculate crystallite size and lattice strain of the KNN powders. The TEM image revealed that the average particle size of the prepared samples is about 30 nm and they have cubic shape. The optical band gap energy of the samples was calculated using UV-vis absorbance spectra of the samples along with Tauc relation. [ABSTRACT FROM AUTHOR]

Hexagonal yttrium manganites, YMnO3, are interesting materials for their multiferroic behavior. Substituting suitable cations either at the Y-site or Mn-site offers great opportunities to produce a variety of manganites and tune their properties. Nanocrystalline yttrium iron manganites with the compositional formula YFeMnO3, = 0.0, 0.10, 0.15, 0.20 and 0.25, were synthesized by sol-gel autocombustion method. The prepared samples were heated at 1100C for 1 h. Another set of samples with compositional formula YFeMnO3, = 0.0, 0.10, 0.15, 0.20 and 0.25, were also synthesized by the same method and heated at 1100C for 1 h. Various characterizations were done on these manganite systems synthesized by substituting iron at different sites. X-ray diffraction (XRD) technique studied the structure of the samples and analysis of XRD patterns confirmed the formation of hexagonal phase in the samples. Structural parameters such as lattice constants, crystallite size, theoretical density, etc. were determined using the XRD data. The unit cell dimensions have been found to agree with the standard data and the Debye-Scherrer crystallite size obtained from XRD data ranges from 42 nm to 77 nm. The room temperature frequency variations of electrical properties such as dielectric constant, dielectric loss and AC conductivity were measured in the range of 100 Hz-2 MHz and the variations showed a dispersive behavior for all the samples. The various measurements and the results obtained were studied and discussed in the paper. [ABSTRACT FROM AUTHOR]

In this paper, we prepared the rattle type nanoparticles ZnO@void@SiO2 by two successive coating processes, followed by heat treatment. The carbon layer was formed over ZnO surface with the aid of the hydrothermal treatment of glucose. Then the resulting composite was used to fabricate a silica shell on the surface by sol-gel method. Finally, ZnO particles were released but still trapped inside the silica hollow after calcination, that is, ZnO@void@SiO2. The composites were characterized by scanning and transmission electron microscope, N2 adsorption experiment, X-ray diffraction, Fourier transform infrared spectroscopy and UV-Vis absorption spectra. The rattle type structure was conformed and the sphere-like structure with the average size of 70 nm and hexagonal wurtzite crystal structure were also observed. The measurement results of optical properties showed even though ZnO@C@SiO2 presented no photocatalysis, ZnO@void@SiO2 showed high activity even the ZnO core was encapsulated with the SiO2 hollow. Rattle-type-structured ZnO@void@SiO2 nanoparticles were prepared by a facile chemical route. The carbonized glucose template and a silica layer were successively coated on the surface of ZnO. The void came out after the removal of carbon layer by calcination. ZnO@void@SiO2 nanoparticles were applied to photo-decomposing MB dye in water solution and showed excellent photocatalytic activity. [ABSTRACT FROM AUTHOR]

In this paper, strontium hexaferrite nanoparticles were synthesized by the sol-gel auto-combustion method. Effect of annealing temperature on crystal structure, morphology and magnetic properties of nanoparticles was investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Also, the thermal decomposition of as-synthesized powdered samples has been studied by thermogravimetric analysis (TGA). The XRD patterns confirmed the formation of single phase M-type hexagonal crystal structure for powders annealed above 950C, whereas the presence of hematite (-Fe2O3) as secondary phase was also observed for sample annealed at 900C. Furthermore, the crystallinity along with the crystallite size were augmented with annealing temperature. Comparison of the FT-IR spectra of the samples before and after annealing treatment showed the existence of metal-oxygen stretching modes after annealing. The thermogravimetric analysis confirmed the thermal decomposition of as-burnt powders happened in three-stage degradation process. The TEM images showed the nanoparticles like hexagonal-shaped platelets as the size of nanoparticles increases by increasing the annealing temperature. With increasing annealing temperature, the magnetic saturation and the coercivity were increased to the maximum value of 74.26 emu/g and 5.67 kOe for sample annealed at 1000C and then decreased. [ABSTRACT FROM AUTHOR]

In this paper, ferrogels comprising nanocrystalline Fe3O4 and γ-FeOOH dispersed in polyvinyl alcohol gel matrix were synthesized via a novel route, without using any cross-linking agent. A moderately high-pressure environment instead was used for the synthesis. The ferrogels were found to be stable over a long period of time and were characterized by transmission electron microscopy (TEM), Mössbauer spectroscopy and DC magnetization studies. TEM studies showed that the particles are mostly spherical with an average size of 10 nm. Mössbauer spectra of the as prepared gels at different temperatures showed the presence of superparamagnetic particles in them. The gels were found to be magnetically ordered at 20 K giving characteristic six-finger Mössbauer patterns. Bulk magnetic properties of the gels were studied by DC magnetization measurements. [ABSTRACT FROM AUTHOR]

Superhydrophobic cotton fabrics are prepared using silica and titania hybrid sol and hexadecyltrimethoxysilane. The surface morphology of cotton fabrics is characterized by scanning electron microscopy. The water contact angles on the as-prepared superhydrophobic cotton fabrics is 159° when the volume ratio between sodium silicate solution and titania sol is 1:3, and the corresponding cotton fabrics can keep the contact angle of 152° after 10 cycles of home machine washing. Meanwhile the treated cotton fabrics can also keep superhydrophobicity after 60 min of UV light irradiation. These results indicate that the cotton fabrics treated with silica and titania hybrid sol and modified with hexadecyltrimethoxysilane show excellent superhydrophobic stability under washing and UV light irradiation. This paper provides the new notion and beneficial reference for the application of the superhydrophobic cotton fabrics in the future. [ABSTRACT FROM AUTHOR]

In this paper, a series of rare-earth-doped barium hexaferrite powders (Ba0.95Re0.05-Fe12O19 and Ba0.95Re0.05M0.05Fe11.95O19: Re = La, Pr, Sm, Nd, Gd, Dy, Yb; M = Zn2+, Mn2+, Mn2+0.5 Zn2+0.5) were synthesized by the sol–gel self-combustion technology. The phase composition and the magnetic properties of the as-prepared barium hexaferrites were characterized and discussed with X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The results showed that the barium hexaferrites exhibited the magnetoplumbite phase structure with the average diameter of 45 nm. Magnetic properties study revealed that the variation of the saturation magnetization (Ms) was similar with the change of the rare-earth ions radius, but the change of Ms was low. This indicated that the magnetic moments of rare-earth ions could not affect Ms. The magnetocrystalline anisotropy field mainly influenced the anisotropism of hexaferrites, and the coercivity (Hc) of the rare-earth ions doped barium hexaferrites basically decreased with the increasing orbital quantum numbers (except Sm3+ and Gd3+). Further study showed the co-addition of Zn2+ and Mn2+ did not change the trend of Ms and Hc. Thus, it is concluded that the rare-earth ions played an important role for the anisotropy field of barium hexaferrites. [ABSTRACT FROM AUTHOR]