Preparation of fine-grained MgO and Gd2O3 stabilized ZrO2 thin films by electron beam physical vapor deposition co-evaporation

1997 ◽  
Vol 12 (12) ◽  
pp. 3260-3265 ◽  
Author(s):  
F. Tcheliebou ◽  
M. Boulouz ◽  
A. Boyer
Keyword(s):  
Thin Films ◽  
Electron Beam ◽  
Average Particle Size ◽  
Electron Gun ◽  
Cubic Phase ◽  
Crystallographic Structure ◽  
Average Particle ◽  
Scanning Electron Micrographs ◽  
Dopant Content ◽  
Fine Grained

Thin films of ZrO2 doped with MgO and Gd2O3, 1–1.5 μm in thickness are formed onto nickel substrates by reactive thermal evaporation using a dual-hearth electron gun. X-ray diffraction patterns of the deposits show changes in the crystallographic structure and average particle size as a function of the dopant content. A mixture of monoclinic and tetragonal phases gradually disappears to become a single cubic phase with increasing dopant molar fraction. The average crystallite size deduced from diffraction line broadening decreases as the dopant content increases. This observation is strongly confirmed by scanning electron micrographs which reveal a smooth surface topography. Fine-grained materials obtained here are interpreted in terms of high nucleation rate and kinetically limited grain growth. It appears that composition, crystallographic structure, and microstructure relations are of paramount importance in ZrO2-based films prepared by electron-beam evaporation.

Surface Characteristics of Ni-Mn-Fe-Ga Sputtered Thin Films

2011 ◽  
Vol 194-196 ◽  
pp. 2290-2295
Author(s):  
Hai Bo Wang ◽  
Jin Yong Xu ◽  
Wei Cai
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Average Particle Size ◽  
Surface Characteristics ◽  
Crystallographic Structure ◽  
Chemical Compositions ◽  
Average Particle ◽  
Alloy Thin Film ◽  
X Ray ◽  
Sputtering Power

The Ni-Mn-Fe-Ga shape memory alloy thin film was deposited onto silicon substrates by using radio-frequency (R.F.) magnetron sputtering technique. Chemical composition, surface morphology and crystallographic structure were systematically investigated by means of X-ray fluorescence (XRF), atomic force microscope (AFM) and X-ray diffraction (XRD). The experimental results show that the magnetron sputtering process has remarkable influence on the chemical compositions and surface characteristics of Ni-Mn-Fe-Ga alloy thin films. As the sputtering power ranging between 245W and 405W, Ni content of the thin films decreases with the sputtering power increasing, whereas Mn and Fe contents increase with increasing the sputtering power and Ga content almost keep a constant. The surface roughness and the average particle size of thin films increase with the increase of Ar working pressure and sputtering power. The film deposited at room temperature has a cubic L21 structure.

A Study of Nanosize Fe3O4 Deposited on Carbon Matrix

2008 ◽  
Vol 8 (2) ◽  
pp. 591-594 ◽  
Author(s):  
B. Banov ◽  
L. Ljutzkanov ◽  
I. Dimitrov ◽  
A. Trifonova ◽  
H. Vasilchina ◽  
...  
Keyword(s):  
Average Particle Size ◽  
Carbon Matrix ◽  
Reversible Capacity ◽  
Carbon Support ◽  
Test Sample ◽  
Constant Current ◽  
Average Particle ◽  
Scanning Electron Micrographs ◽  
Lithium Secondary Batteries ◽  
Electrochemical Tests

Nanosized crystalline Fe3O4 (with an average particle size of 16 nm) was successfully synthesized on a carbon matrix surface. The prepared sample was heat-treated in the temperature range 300 °C–750 °C to remove residual impurities and to obtain a final product with a 77:23 ratio between magnetite and the carbon support. The sample was subjected to physicochemical and electrochemical tests. The purity of the phase and the particles size was determined by X-ray diffraction analysis and confirmed by field emission scanning electron micrographs. The specific surface area of the sample measured by the B.E.T method was 120 m2 g−1. A series of electrochemical tests including EIS, CV and long-term constant current cycling have been performed. The obtained reversible capacity within 15 cycles was in the range 400–550 mA h · g−1. The electrochemical behavior of the test sample and its possible practical use as an anode material in lithium secondary batteries are discussed.

Polyaniline: Thin films and colloidal dispersions (IUPAC Technical Report)

2005 ◽  
Vol 77 (5) ◽  
pp. 815-826 ◽  
Author(s):  
Jaroslav Stejskal ◽  
Irina Sapurina
Keyword(s):  
Thin Films ◽  
Dispersion Polymerization ◽  
Average Particle Size ◽  
Colloidal Dispersions ◽  
Water Soluble ◽  
Average Particle ◽  
Water Soluble Polymer ◽  
Ammonium Peroxydisulfate ◽  
Technical Report

Several workers from various institutions in six countries have prepared thin films and colloidal polyaniline dispersions. The films were produced in situ on glass supports during the oxidation of anilinium chloride with ammonium peroxydisulfate in water. The average thickness of the films, assessed by optical absorption, was 125 ± 9 nm, and the conductivity of films was 2.6 ± 0.7 S cm–1. Films prepared in 1 mol l–1 HCl had a similar thickness, 109 ± 10 nm, but a higher conductivity, 18.8 ± 7.1 S cm–1. Colloidal polyaniline particles stabilized with a water-soluble polymer, poly(N-vinylpyrrolidone) [poly(1-vinylpyrrolidin-2-one)], have been prepared by dispersion polymerization. The average particle size, 241 ± 50 nm, and polydispersity, 0.26 ± 0.12, have been determined by dynamic light scattering. The preparation of these two supramolecular polyaniline forms was found to be well reproducible.

FABRICATION AND CHARACTERIZATION OF AQUEOUS SOL–GEL-DERIVED LaFeO3 THIN FILMS

2000 ◽  
Vol 14 (22n23) ◽  
pp. 801-808 ◽  
Author(s):  
M. RAJENDRAN ◽  
M. GHANASHYAM KRISHNA ◽  
A. K. BHATTACHARYA
Keyword(s):  
Thin Films ◽  
Single Phase ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Average Particle Size ◽  
Optical Transmittance ◽  
Dip Coating ◽  
Correlation Spectroscopy ◽  
Average Particle ◽  
X Ray

A novel all-inorganic aqueous sol–gel process has been developed to fabricate LaFeO3 thin films by dip-coating. Stable, positively charged colloidal sol particles of hydrous lanthanum ferrite with an average particle size (Z av ) of 7 nm were prepared and coated onto quartz plates under controlled conditions. The sols have been characterized using photon correlation spectroscopy (PCS) for Z av and size distribution. The redispersible gel was characterized by thermogravimetric and differential thermal analysis (TG-DTA) and also by isothermal heating followed by X-ray diffraction to identify the reaction sequence to form LaFeO 3. The sol–gel films as deposited were X-ray amorphous on heating up to 500°C, partially crystalline at 600°C, fully crystalline and single phase at 650°C and above. These films were continuous, polycrystalline, single phase, had uniform thickness in the range between 180 to 1000 nm, depending on deposition conditions, and showed about 80% optical transmittance. The optical band gap varied from 2.7 to 3.3 eV as a function of the annealing temperature. The refractive index increased with increase in annealing temperature from 1.55 at 500°C to 1.86 at 800°C.

Exchangeable calcium, magnesium and sodium and the dispersion of illites in water. I. Characterization of illites and exchange reactions

Soil Research ◽  
1977 ◽  
Vol 15 (3) ◽  
pp. 243 ◽  
Author(s):  
CL Chi ◽  
WW Emerson ◽  
DG Lewis
Keyword(s):  
Surface Area ◽  
Divalent Cations ◽  
Average Particle Size ◽  
Type Equation ◽  
Direct Calculation ◽  
Double Layers ◽  
Average Particle ◽  
Exchange Reactions ◽  
Fine Grained ◽  
Calcium Magnesium

Three 'pure' illites were studied. Two, extracted from soils, were fine grained, and the other coarse, extracted from a shale. The average particle size of each clay was determined from electron micrographs and a specific surface area calculated. For the two soil illites any difference in the surface area deduced from water vapour sorption as compared with nitrogen sorption or by direct calculation, was consistent with the purity of the clay as determined by X-ray diffraction. For the shale, there was a large discrepancy, which is attributed to this illite having a greater surface density of charge. For the two soil illites, the exchange of calcium or magnesium for sodium, over the ESP range 0-12 and the calcium-magnesium exchange isotherms were determined. The exchange of sodium followed the same Gapon-type equation for both clays, and was independent of whether calcium or magnesium was the dominant cation. The calcium-magnesium isotherms were also symmetrical. No evidence was therefore found for calcium ions being more strongly held at exchange sites than magnesium ions. It was shown that in the solutions used to equilibrate the clays, which were 1 mM in divalent cations, diffuse double layers were not formed.

Preparation of Ag Nanoparticles by Particulate Radiation of Pulsed Electron Beam

2011 ◽  
Vol 287-290 ◽  
pp. 338-342
Author(s):  
Young Rang Uhm ◽  
Chang Kyu Rhee ◽  
Sergei Sokovnin ◽  
M.E Balezin
Keyword(s):  
Particle Size ◽  
Electron Beam ◽  
Ethylene Glycol ◽  
Ag Nanoparticles ◽  
Irradiation Time ◽  
Average Particle Size ◽  
Pulse Electron Beam ◽  
Average Particle ◽  
Beam Irradiation ◽  
Pulsed Electron Beam

Nano metal Ag nanoparticles were synthesized by pulse electron beam (e-beam) irradiation at room temperature and the atmospheric pressure. The staring materials were AgNO3, toluene, ethanol and ethylene glycol. The ethanol and ethylene glycol plays a role of prohibiting agglomeration of metal ions. Energy dispersive X-ray spectrometer (EDX) was used to characterize the elements. Transmission electron microscopy (TEM) images were used to determine the shape and diameter. The time of e-beam irradiation affect to the particle size and aggregation. The average particle size was 10 nm and 30 nm for the dose time of 1 and 5 min, respectively. The shape of particles were changed from spherical to disk-like to coral-like, with increasing the irradiation time from 1 to 5 to 10 min.

Nanocrystalline BaTiO3 from freeze-dried nitrate solutions

1996 ◽  
Vol 11 (5) ◽  
pp. 1199-1209 ◽  
Author(s):  
J. M. McHale ◽  
P. C. McIntyre ◽  
K. E. Sickafus ◽  
N. V. Coppa
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
High Surface ◽  
Nitrate Solution ◽  
Average Particle Size ◽  
Volume Ratio ◽  
Product Formation ◽  
Cubic Phase ◽  
Average Particle ◽  
Freeze Dried

An aqueous, all nitrate, solution-based preparation of BaTiO3 is reported here. Rapid freezing of a barium and titanyl nitrate solution, followed by low temperature sublimitation of the solvent, yielded a freeze-dried nitrate precursor which was thermally processed to produce BaTiO3. XRD revealed that 10 min at temperatures ≧600 °C resulted in the formation of phase pure nanocrystalline BaTiO3. TEM revealed that the material was uniform and nanocrystalline (10–15 nm). The high surface to volume ratio inherent in these small particles stabilized the cubic phase of BaTiO3 at room temperature. It was also found that the average particle size of the BaTiO3 produced was highly dependent upon calcination temperature and only slightly dependent upon annealing time. This result suggests a means of selection of particle size of the product through judicious choice of calcination temperature. The experimental details of the freeze-dried precursor preparation, thermal processing of the precursor, product formation, and product morphology are discussed.

Magnetotransport and Structural Properties of Nanocrystalline FeAgAl Thin Films

2008 ◽  
Vol 8 (8) ◽  
pp. 4068-4072 ◽  
Author(s):  
P. B. Patil ◽  
S. Rout ◽  
A. R. B. Rao ◽  
M. Senthil Kumar
Keyword(s):  
Thin Films ◽  
Average Particle Size ◽  
Partial Substitution ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Al Content ◽  
Transmission Electron ◽  
Standard Value ◽  
Magnetoresistance Ratio ◽  
Xrd Patterns

Structural and magnetotransport properties of metallic FexAgyAlz nanogranular thin films were studied. These films with several compositions were prepared by dc magnetron sputtering. X-ray diffraction (XRD) measurements carried out on the samples show only Ag(111) peaks. The d-spacings determined from the Ag(111) peaks are smaller than the standard value for bulk Ag indicating a partial substitution of Fe and Al atoms in Ag matrix. Transmission electron diffraction (TEM) patterns show a number of Ag rings. Both XRD and TEM studies did not reveal any diffraction peaks due to Fe or Al. The average particle size determined from the TEM micrograph is 5.9 nm. This value is in good agreement with the grain size determined from the XRD patterns for the Al substituted samples. The MR was found to increase for smaller Al concentration and it decreases with further increase in Al content. In the samples investigated magnetoresistance ratio reaches a maximum value of about 4.5% for the Fe27 Ag63Al10 film.

scholarly journals Structure and dielectric behaviour of Sr-modified Bi4Si3O12 thin films prepared via sol gel method

2018 ◽  
Vol 12 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Abbas Sadeghzadeh-Attar ◽  
Saeid Hajijafari-Bidgoli ◽  
Mohammad Bafandeh
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Loss ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Average Particle Size ◽  
Average Particle ◽  
Sem Images ◽  
Gel Method ◽  
Sol Gel Method

Bismuth silicate (Bi4Si3O12, BSO) nanostructured films containing 0,1,2, and 3mol% Sr were prepared via sol-gel method and annealed at different temperatures up to 700?C. The effects of Sr content on the structure and morphology of prepared films were investigated. SEM images showed that surfaces of the prepared films were dense, smooth and homogeneous. The average particle size was changed from 30 to 35 nm as the annealing temperature was increased from 500 to 700?C. Variation of the dielectric constant and dielectric loss as a function of frequency and annealing temperature for the synthesized thin films with different content of Sr were also studied. The dielectric constant and dielectric loss decrease with Sr addition, and reach the minimum for the sample containing 2mol% Sr. These changes could be attributed to the crystal structure and formation of secondary phases.

scholarly journals Synthesis, characterization, and optical properties of copper oxide thin films obtained by spray pyrolysis deposition

2019 ◽  
Vol 11 (22) ◽  
pp. 64-71
Author(s):  
Rawaa A. Faris
Keyword(s):  
Thin Films ◽  
Copper Oxide ◽  
Spray Pyrolysis ◽  
Average Particle Size ◽  
Average Particle ◽  
Oxide Thin Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Spray Pyrolysis Deposition ◽  
Xrd Patterns

     Copper oxide thin films were synthesized by using spray pyrolysis deposition technique, in the temperature around 400°C in atmosphere from alcoholic solutions. Copper (II) chloride as precursor and glass as a substrate. The textural and structural properties of the films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD). The average particle size determined from the AFM images ranged from 30 to 90 nm and the roughness average was equal to 9.3 nm. The XRD patterns revealed the formation of a polycrystalline hexagonal CuO. The absorption and transmission spectrum, band gap, film thickness was investigated. The films were tested as an optical limiter. The experiments were performed using Q-switched Nd:YAG laser at 532nm and 1064 nm at different intensities. Copper oxide thin films appear to be attractive candidates for optical limiting application and sensor application.

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