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The soft magnetic properties of Fe-based nano-crystalline alloys depend on the size, shape and crystallization ratio of nanocrystals formed during annealing. To increase saturation magnetization, soft magnetic properties should be reduced by increasing Fe content. Amorphous Fe-B-C-Cu alloys have been reported to be successfully fabricated despite a Fe content of more than 84%. However, clustered rectangular nano-grains were formed during annealing, resulting in an increase in magnetic loss. In this study, to induce the uniform formation of nuclei and suppress crystal clustering, the effects of C, Cu and Nb on the magnetic and microstructural properties of Fe(81-x)B12.5CyCuxNb(6.5-y) (x = 0, 1, 2 and y = 1, 2, 3, 4) were investigated. The results indicated that thermal stability played an important role in the formation of uniformly distributed spherical nano-crystals during annealing.

Nano-crystalline Ti2SC powders were synthesized by a molten salt method with TiS2/3Ti/2C powders as raw materials and KCl–NaCl as the molten salt medium under argon protection. The effect of heat treatment temperature on the composition and morphology of Ti2SC powder was studied. Ti2SC powder can be synthesized at a relatively low temperature by the molten salt method. A high content of Ti2SC powder can be obtained at 1150 °C for 1.5 h. The particle size of the powder was 22.6 nm. Scanning electron microscopy and transmission electron microscopy showed that nano-sized Ti2SC had an average particle size of 20–30 nm.

Objective: Phosphorus doped hydrogenated nano-crystalline silicon (nc-Si:H) thin films were synthesized by catalytic chemical vapor deposition (Cat-CVD) method. Methods: The effect of deposition pressure on opto-electronic and structural properties was studied using various analysis techniques such as low angle XRD analysis, FTIR spectroscopy, Raman spectroscopy, UV-Visible spectroscopy, dark conductivity, etc. Results: From low angle XRD and Raman spectroscopy analysis, it is observed that an increase in deposition pressure causes Si:H films to transform and transit from amorphous to the crystalline phase. At optimized deposition pressure (300 mTorr), phosphorous doped nc- Si:H films having a crystallite size of ∼29 nm and crystalline volume fraction of ∼58% along with high deposition rate (∼29.7 Å/s) have been obtained. The band gap was found to be ∼1.98 eV and hydrogen content was as low as (∼1.72 at. %) for these films. Conclusion: The deposited films can be useful as an n-type layer for Si:H based p-i-n, tandem and c-Si hetero-junction solar cells.

Anatase TiO2 surfaces have been treated with 2, 4, 6-triphenylpyrylium hydrogen sulfate (TPPHS) or tripyridylporhpyrinatomanganese(II) (MnP) dyes to yield the modified TiO2/ dye surfaces. The modified TiO2/dye surface was then supported onto activated carbon (AC) surfaces to yield a new class of catalytic system AC/TiO2/dye. The catalytic activities of naked TiO2, dye solution, TiO2/dye, and AC/TiO2/dye systems were examined in photo-degradation of Methamidophos (insecticide) in water, using both UV and visible light. All examined systems showed catalytic activity when used either in the UV or the visible regions, but the AC/TiO2/ dye showed the highest activity. The dye role, in enhancing activity of modified surfaces in UV degradation of the examined contaminants, is understandable by a charge-transfer catalytic effect. AC role can be explained by its ability to adsorb contaminant molecules and bringing them closer to catalytic sites. There was no significant temperature effect on catalyst efficiency in Methamidophos photo-degradation. Oxygen is essential for semiconductor photocatalytic degradation of Methamidophos, but higher oxygen concentrations lead to a downturn of the reaction rate.

In this paper, TiO2 is substituted as a nucleating agent in opaque glaze to produce nano-crystalline glaze with high hardness. The crystallization mechanism of glaze was calculated by non-isothermal thermal analysis by Differential Thermal Analysis (DTA), and the glaze was heat treated at the crystallization temperature (Tp). In the case of glaze (88G20T), in which TiO2 was substituted by 20 wt% showed surface crystallization behaviors because the Avrami constant (n) was 1.18 and the activation energy (E) values were 747.0 kJ/mol at the crystallization temperature (Tp2). The microstructure of the glazes without heat-treatment showed that phase separation transferred from spinodal to nucleation-growth as TiO2 substitution increased. The size of droplets was nano-sized, below 100 nm. The glazes heated at the crystallization temperature (Tp) and crystal size of several hundred nm to several μm was observed. The surface hardness of the crystalline glaze showed a high hardness of 6.74 GPa and the degree of crystallization was 47.5% at 80G20T after heat treatment at Tp2 (1207 °C).

Co1–xZnxFe2O4 (x = 0.2, 0.4, 0.6 and 0.8) were synthesized using typical wet chemical co-precipitation technique. The ferrite specimen have been sintered at 700°C and 900°C for three hours in air. ...

Nano crystalline powder of Co–Ni ferrites compounds having the chemical formula Ni1-xCoxFe2O4 with x = 0.0, 0.25, 0.5, 0.75 and 1.0 were prepared by co-precipitation method. The nanoparticles were ...

Through-pores alumina membranes of 50 μm thickness and 70 × 70 mm size have been fabricated to deposit Ni nanowires by electrochemical processing. Due to highly ordered microstructure of the membranes, the pores were filled by nanowires almost to 100%. The membrane nanowires composite morphology, structure and thermodynamic characteristics have been studied by scanning electron microscopy, atomic-force microscopy, X-ray diffraction and differential thermal analysis. The thermal stability of Ni nanowires into porous alumina template and whole composite was determined.

Mg0.2Mn0.8NdxFe2-xO4 (x = 0.000, 0.025, 0.050, 0.075 and 0.010) nano crystalline is synthesized via hydrothermal technique. Single cubic spinel phase is confirmed by XRD and the formation of Mg0.2M...

We report chemical vapor deposition (CVD) and photoelectrochemical properties of large-area thin films of nano-crystalline SnSe2 on conducting FTO glass. We show that densely packed, randomly oriented SnSe2 nanoflakes can be grown by reacting vapors of tin monoselenide (SnSe) and selenium at 550 °C without compromising the electrical properties of FTO. We demonstrate that SnSe2/FTO is photoelectrochemically active in visible to near-UV wavelengths (350–700 nm) and exhibits incident-photon-to-current-efficiency (IPCE) as high as 3.7% at 0 V versus the Ag/AgCl/1 M KCl reference electrode under 350 nm light illumination.

The contributing effects of Si inclusion on the fabrication and performance of the Fe-based amorphous/nano-crystalline alloys were extensively studied with the first principle molecular dynamics simulation method. Si is found to have complicated impact on the formation of amorphous structure as it is structurally preferred to crystallize with Fe but energetically beneficial to stabilize the amorphous when reaching high concentration. The inclusion of Si is also found to cause the increase of the crystallization temperature and give rise to better controllability of the nano-crystallization process for better magnetic softness. Magnetically, Si can always reduce the saturation magnetization in the Fe-based alloy but also can indirectly help decreasing the overall coercivity of the Fe-based nano-crystalline alloy.

Nano-crystalline magnesium ferrite was prepared by oxalate co-precipitation method. The sample was presintered and sintered by microwave technique. It was characterized by X- ray diffraction; Scann...

Current material research is exploring new strategies by tailoring the properties of the dielectric ceramic materials. Dramatic alteration can be done on the most of the properties of micro crystal...

Nano-crystalline Co 3 O 4 spinel powder has been successfully synthesized via a simple, template and surfactant free homogeneous precipitation method in short time followed by heat treatment at low temperature (350°C). The prepared samples were characterized by powder X-ray diffraction, fourier transform infrared spectroscopy, thermal gravimetric analysis and transmission electron microscopy.

Because of the technological applications, Niobium based ceramic is one of the most research interest. Thus, there is numerous research works in recent years on their application as electronic and optical devices. Sintered oxide ceramics, having the required shape, micro structured size can be used for different electronic applications. In this paper, nano crystalline Sr6Sb4NbO18 ceramic was prepared by combustion method. The sample was analysed by the X-ray diffraction, TEM, radio frequency and Impedance spectroscopic studies. The XRD pattern of as prepared Sr6Sb4NbO18 sample reveals, the material has rhombohedral perovskite structure. All the peaks were broad when compared with the bulk, which indicates the reduction in the crystallite size. This is due to the micro strain and nano size in the crystallites. The crystallite size has been calculated from the XRD data, using Scherrer formula and it was obtained as 21 nm. The surface morphology of as prepared sample was studied using TEM and the particle size was found to be 19 nm. The sample was sintered at 1050 °C, obtained the 98 % of theoretical density. An impedance spectroscopic study of the sample carried out with a temperature range of, 200 °C to 500 °C shows that the ions are the main source for the conduction. The reason for the conductivity of the material might be because of the grain and grain boundary effects which can be clearly seen in the impedance plot. The impedance study confirms that the material is a possible candidate to fabricate solid oxide fuel cell.

In this work we have successfully prepared spherical and chain type silver nanoparticles of excellent size’s homogeneity, reproducibility and stability using tannic acid. The synthesized nanometallic structures were characterized for their shape, size, thermal stability and crystalline nature. The mechanism for the formation of Ag NPs and shape evolution of the chain structure has been vividly explained. Further, these NPs were found to exhibit significant antibacterial activity against gram negative Escherichia coli bacteria but to different extend indicating the influence of particles morphology on their antibacterial behaviours. Copyright © 2015 VBRI Press.

Carbide free nano-bainitic (NSB) steels have a dual phase structure comprising of retained austenite (RA) and bainitic ferrite (BF). The content and morphology RA and BF in NSB steels can be easily modulated by changing the austempering temperature. This results in significant changes in the strength and is expected to influence the corrosion resistance as well. The corrosion behavior of three NSB steel blocks austempered at 250, 300 and 350 °C has been studied in aqueous chloride (3.5 wt% NaCl) environment. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization have been used to investigate the role of austempering temperature on the corrosion response. It is found that the corrosion current density and hence the corrosion rate decreases with a reduction in austempering temperature. Moreover, a reduction in the austempering temperature shifts the corrosion potential towards the nobler side. The EIS studies have shown that the charge transfer resistance gets enhanced for specimens austempered at lower temperatures. This comes with a concomitant lowering in the capacitance of the electrical double layer formed between the steel specimen and electrolyte. Thus, it is possible to achieve a combination of high hardness and corrosion resistance by fabricating the NSB steels at low austempering temperatures.

A novel nanostructured HoCrO4 material with zircon type structure with Cr(+V) species was prepared by fuel deficient combustion method. The prepared material was well characterized by using XRD, TEM, BET and TPD techniques. Wide range of aromatic aldehydes were effectively coupled with malononitrile in an aqueous media over HoCrO4 in merely 15 to 20 min at room temperature. To the best of our knowledge this is the first catalytic application of HoCrO4 material.

Herein, several nitrogen-doped nano-crystalline graphite films (N-NCG) were prepared via plasma-enhanced chemical vapor deposition (PECVD); nano-crystalline graphite (NCG) was doped by adding ammonia gas during the PECVD growth. To develop electrochemical probes that can compete with glassy carbon (GC) electrodes for anthracene sensing, the N-NCG electrodes were systematically investigated using different techniques, including atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, Raman spectroscopy, cyclic voltammetry (CV), and differential pulsed voltammetry (DPV). The obtained sensors were tested against anthracene in an acetonitrile/water mixture (80/20 v/v) wherein the N-NCG 3 and N-NCG 5 electrochemical probes showed analytical features comparable with those of the GC electrode. The best competitor for GC was N-NCG 3 in terms of linear working range (2.5 μM–1 mM) and sensitivity (y = 6.09 × 10−6 + 1.21 x, r2 = 0.9997 and y = 1.23 × 10−5 + 0.84 x, r2 = 0.9959 for GC and N-NCG 3, respectively).

The CuIn1 – xGaxSe2 (CIGS) (x = 0.3) nanocrystalline powder was synthesized by reacting to its constituent elements i.e. Copper, Indium, Gallium, and Selenium in a SPEX mill. The SPEX mill is a high-energy mill where the reaction between constituent elements takes place in solid-state to form a nanocrystalline compound powder. SPEX mill consists of tungsten lined hardened steel vials and tungsten carbide balls are used as grinding media. Three different size grinding media was used with ball to charge ratio of 10 : 1. The optimization of milling time was studied to obtain CIGS nanocrystalline powder using SPEX mill. The phase analysis by X-ray diffraction shows the formation chalcopyrite (tetragonal) structure of CIGS after 4 h of high-energy milling with an average crystallite size of 10-13 nm. Raman spectra peak at 174 cm – 1 confirms the formation of the CIGS phase. The compositional analysis by EDAX confirms the formation of the stoichiometric composition of CIGS. This study reveals that it is possible to synthesize CIGS nanocrystalline powder using SPEX mill.

Nano-structures play an important role in oil-water separation, and it has recently been shown that nano-particles of titanium dioxide succeed in oil-water separation. In the current study, the behavior of oil-water mixture on a titanium dioxide substrate in the presence and in the absence of surfactant was studied using molecular dynamics simulation. Simulation results indicate that in the presence of surfactant, the oil-water interfacial tension decreases as a result of hydrogen bonding between water and the hydrophilic head of the surfactant. This is particularly illustrated by the calculation of both lifetime as well as number of hydrogen bonds and leads to the separation of water from oil.

The search precursors that are bio-based, renewable and biodegradable has attracted significant attention due to increased environmental awareness. Recently, nano-crystalline cellulose (NCC) has been considered as a potential precursor to produce carbon fibre owing to its high crystallinity and excellent mechanical properties. However, its crystallinity prevents it from being dissolved in comment solvents. The main aims of this study were: (i) to acetylate NCC to improve its compatibility with cellulose acetate and (ii) to produce wet-spun cellulose acetate fibres reinforced acetylated and unacetylated NCC. In this study, rod-like particles of NCC with diameters in the range 2.0-4.8 nm and lengths of 46-114 nm were characterised using a Transmission Electron Microscope (TEM). The carbonyl (C=O) group of the acetyl group was confirmed using Fourier Transmission Infrared (FTIR), and the crystallinity of NCC was characterised using X-Ray Diffraction (XRD). The crystallinity indicates of the NCC before and after acetylation were 78% and 68% respectively. The morphology of wet-spun cellulose acetate reinforced acetylated NCC was smoother than reinforced NCC. The acetylation on NCC increased its compatibility with the polymer matrix.

Currently, the two technologies primarily used for the manufacturing of nano-crystalline suspensions using top down process (i.e. wet milling) are high pressure homogenization (HPH) and stirred bead milling (SBM). These two technologies are based upon different mechanisms, i.e., cavitation forces for HPH and shear forces for stirred bead milling. In this article, the HPH and SBM technologies are compared in terms of the impact of the suspension composition the process parameters and the technological configuration on milling performances and physical quality of the suspensions produced. The data suggested that both HPH and SBM are suitable for producing nano-crystalline suspensions, although SBM appeared more efficient than HPH, since the limit of milling (d50) for SBM was found to be lower than that obtained with HPH (100 nm vs 200 nm). For both these technologies, regardless of the process parameters used for milling and the scale of manufacturing, the relationship of d90 versus d50 could be described by a unique master curve (technology signature of milling pathway) outlining that the HPH leads to more uniform particle size distribution as compared to SBM.

The aim of this work was to determine the effect of temperature, precursor and dripping time on the crystallite size of ZnO nanoparticles synthesized by controlled precipitation according a 2k full factorial design. ZnCl2, Zn(NO3)2 and NaOH were used as precursors. After synthesis, the nano crystalline powder was characterized by XRD (Cu Kα), UV-Vis, and HR-TEM. The nano ZnO particles presented a crystallite size between 210 and 260 A (HR-TEM and XRD). The results show that the crystallite size depends on the type of precursor and temperature of synthesis, but not on the dripping time.

The possibilities of applying the technology of plasma-chemical deposition of films of a-Si1-xGex: H (x=0 ÷ 1), undoped and doped with PH3 and B2H6, for use in a pin-structure solar cells. The optical, electrical and photoelectric properties, as determined by the amount of hydrogen of the film. We found that the property of the film strongly depends on the composition and level of hydrogenation. The number of hydrogen atoms in the films was varied by changing the composition of the gas mixture and measured the infrared absorption films a-Si:H and a-Ge:H.

Sb-doped SnO2 (ATO) thin films have been prepared using the spin coating method by selecting the proper amount of acetylacetone as solution modifier. All ATO powders and films exhibited the cassiterite rutile-like structure in a crystal size below 10 nm under all the experimental conditions and a nonpreviously reported crystal structure was observed at high acetylacetone loads. The acetylacetone molar ratio influenced notably the optical and electrical properties of ATO films. When prepared at an acetylacetone molar ratio of 4, ATO films exhibited optical transparencies above 90% in the visible region and above 40% in the UV region for thicknesses of 100 and 300 nm. Films in a thickness of 100 nm and at an annealing temperature of 650 °C accounted for a high transparency of 97% in the visible wavelength. Films prepared at an acetylacetone molar ratio of 4 exhibited an electric resistivity of 1.33×10-3 Ω·cm at an annealing temperature of 650 °C. The optimal Sb content for ATO films was found to be 8 at%. The relationships among the properties of starting solutions, the experimental parameters, and properties of ATO films are discussed.