Synthesis and Characterization of Nanocrystalline Barium–Samarium Titanate

2016 ◽  
Vol 35 (5) ◽  
pp. 499-505 ◽  
Author(s):  
M. M. Hessien ◽  
Nader El-Bagoury ◽  
M. H. H. Mahmoud ◽  
Osama M. Hemeda

AbstractBarium–samarium titanate nanopowder (Ba0.85 Sm0.1TiO3) was synthesized through tartrate precursor route. The effect of annealing temperature on the formation, crystalline size, morphology and magnetic properties was systematically studied. The annealing temperature was varied from 600°C to 1,100°C. Thermal analysis measurement (TG-DSC, thermogravimetry-differential scanning calorimetry) was carried out on the precursor to characterize the thermal decomposition behavior. The results showed that the precursor of Ba–Sm–Ti mixture decomposed thermally in multistep weight loss up to about 480°C and perovskite Ba0.85Sm0.1TiO3 started to form at ~520°C. X-ray diffraction and Fourier transform infrared (FTIR) spectroscopic measurements showed that the synthesized Ba0.85Sm0.1TiO3 has a tetragonal dominant structure with the presence of intermediate SmTi2O3 at lower annealing temperature. The ratio of SmTi2O3 was decreased and completely disappeared at higher annealing temperatures. The tetragonality, the theoretical density and the crystalline size were increased by increasing annealing temperature. The crystalline size is still in nano-range of 12.4–19.9 nm even after annealing at 1,100°C. The morphology of the produced sample transferred from nano-cubes to nano-whisker to nano-mace (nano-aggregates) with the increase of annealing temperature.

2018 ◽  
Vol 36 (2) ◽  
pp. 193-202 ◽  
Author(s):  
A.M. Abd-Elnaiem ◽  
M. Mohamed ◽  
R.M. Hassan ◽  
M.A. Abdel-Rahim ◽  
A.A. Abu-Sehly ◽  
...  

Abstract Effect of annealing temperature on the structural and optical properties of As30Te60Ga10 thin film was studied using various techniques such as differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The DSC analysis revealed that the As30Te60Ga10 glass has a single glass transition and crystallization peak while XRD results confirmed that the as-prepared and annealed films have crystalline nature. The coexistence of the crystalline phases in the investigated films could be attributed to the formation of orthorhombic As, hexagonal Ga7Te10, and monoclinic As2Te3 phases. It was found that the average crystallite size and optical parameters of the studied films depend on the annealing temperature. For example, the optical band gap decreased from 1.54 eV to 1.11 eV as the annealing temperature increased from 300 K to 433 K.


2019 ◽  
Vol 9 (01) ◽  
pp. 21-26
Author(s):  
Arif Budiman ◽  
Ayu Apriliani ◽  
Tazyinul Qoriah ◽  
Sandra Megantara

Purpose: To develop glibenclamide-nicotinamide cocrystals with the solvent evaporation method and evaluate their solubility and dissolution properties. Methods: Cocrystals of glibenclamide-nicotinamide (1:2) were prepared with the solvent evaporation method. The prediction of interactive cocrystals was observed using in silico method. The solubility and dissolution were performed as evaluation of cocrystals. The cocrystals also were characterized by differential scanning calorimetry (DSC), infrared spectrophotometry, and powder X-ray diffraction (PXRD). Result: The solubility and dissolution profile of glibenclamide-nicotinamide cocrystal (1:2) increased significantly compared to pure glibenclamide as well as its physical mixture. Characterization of cocrystal glibenclamide-nicotinamide (1:2) including infrared Fourier transform, DSC, and PXRD, indicated the formation of a new solid crystal phase differing from glibenclamide and nicotinamide. Conclusion: The confirmation of cocrystal glibenclamide-nicotinamide (1:2) indicated the formation of new solid crystalline phases that differ from pure glibenclamide and its physical mixture


Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.


Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 261
Author(s):  
Adolfo Bucio ◽  
Rosario Moreno-Tovar ◽  
Lauro Bucio ◽  
Jessica Espinosa-Dávila ◽  
Francisco Anguebes-Franceschi

A study on the physical and mechanical properties of beeswax (BW), candelilla wax (CW), paraffin wax (PW) and blends was carried out with the aim to evaluate their usefulness as coatings for cheeses. Waxes were analyzed by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC), permeability, viscosity, flexural and tensile tests and scanning electron microscopy. Cheeses were coated with the waxes and stored for 5 weeks at 30 °C. Measured parameters were weight, moisture, occurrence and degree of fractures, and dimensional changes. The crystal phases identified by XRD for the three waxes allowed them to determine the length of alkanes and the nonlinear compounds in crystallizable forms in waxes. FTIR spectra showed absorption bands between 1800 and 800 cm−1 related to carbonyls in BW and CW. In DSC, the onset of melting temperature was 45.5 °C for BW, and >54 °C for CW and PW. Cheeses coated with BW did not show cracks after storage. Cheeses coated with CW and PW showed microcraks, and lost weight, moisture and shrunk. In the flexural and tensile tests, BW was ductile; CW and PW were brittle. BW blends with CW or PW displays a semi ductile behavior. Cheeses coated with BW blends lost less than 5% weight during storage. The best waxes were BW and the blends.


2013 ◽  
Vol 539 ◽  
pp. 19-24 ◽  
Author(s):  
Yong Qi Wei ◽  
Wu Yao

The quantitative characterization of hydration of cement pastes has always been one of focuses of researchers’ attention. Rietveld phase analysis (RPA), a combination of quantitative X-ray diffraction (QXRD) and the Rietveld method, supplies a tool of an enormous potential for that. Although a few of related researches were conducted by RPA, the reported attention was not paid to the neat cement paste with a low w/c ratio. Therefore, this work aimed at the quantitative study on hydration of such a cement paste chiefly by this method, meanwhile, cooperated with the hyphenated technique of thermogravimetry with differential scanning calorimetry (TG-DSC), as a spot check. Results indicated that RPA was a reliable method in quantitatively characterizing hydration of cement pastes, and gave a clear decription of evolution of all main crystal phases in cement pastes; and that the evolution of monosulphate(Afm_12) was also able to be tracked quantitatively. This will help to understand better the hydration mechanism of cement pastes, as well as to investigate quantitatively effects of mineral and chemical admixtures on hydration of composite cementitious systems.


Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3035
Author(s):  
Dovydas Karoblis ◽  
Diana Griesiute ◽  
Kestutis Mazeika ◽  
Dalis Baltrunas ◽  
Dmitry V. Karpinsky ◽  
...  

In this study, a highly crystalline bismuth ferrite (BFO) powder was synthesized using a novel, very simple, and cost-effective synthetic approach. It was demonstrated that the optimal annealing temperature for the preparation of highly-pure BFO is 650 °C. At lower or higher temperatures, the formation of neighboring crystal phases was observed. The thermal behavior of BFO precursor gel was investigated by thermogravimetric and differential scanning calorimetry (TG-DSC) measurements. X-ray diffraction (XRD) analysis and Mössbauer spectroscopy were employed for the investigation of structural properties. Scanning electron microscopy (SEM) was used to evaluate morphological features of the synthesized materials. The obtained powders were also characterized by magnetization measurements, which showed antiferromagnetic behavior of BFO powders.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Jiangtao Xing ◽  
Weili Wang ◽  
Wenzheng Xu ◽  
Tianle Yao ◽  
Jun Dong ◽  
...  

In order to improve the safety of hexanitrohexaazaisowurtzitane (CL-20), submicron CL-20 particles were prepared by a siphon ultrasonic-assisted spray refining experimental device. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC), and the impact sensitivity of the samples was tested. The results show that the particle size of siphon-refined CL-20 is about 800 nm~1 μm, which is more smooth, mellow, and dense than that of CL-20 prepared by a traditional pressure-refined method. The peak diffraction angle of pressure- and siphon-refined CL-20 is basically the same as that of raw CL-20, and their crystal forms are ε type. The peak strength of pressure- and siphon-refined CL-20 decreased obviously. The apparent activation energy of pressure-refined CL-20 and siphon-refined CL-20 is 13.3 kJ/mol and 11.95 kJ/mol higher than that of raw CL-20, respectively. The thermal stability of CL-20 is improved. The activation enthalpy (ΔH#) is significantly higher than that of raw CL-20, and the characteristic drop is 70.4% and 82.7% higher than that of raw CL-20. The impact sensitivity of siphon-refined CL-20 is lower than that of pressure-refined CL-20, so the safety performance of an explosive is improved obviously.


Author(s):  
S. Louki ◽  
N. Touach ◽  
A. Benzaouak ◽  
V. M. Ortiz-Martínez ◽  
M. J. Salar-García ◽  
...  

This work investigates the photocatalytic activity of new ferroelectric material with formula (Li0.95Cu0.15)Ta0.76Nb0.19O3 (LT76) in a single chamber microbial fuel cell (MFC) and compares its performance with the similar photocatalyst (Li0.95Cu0.15)Ta0.57Nb0.38O3 (LT57). The photocatalysts LT76 and LT57 were synthesized by ceramic route under the same conditions, with the same starting materials. The ratio Ta/Nb was fixed at 4.0 and 1.5 for LT76 and LT57, respectively. These phases were characterized by different techniques including X-ray diffraction (XRD), transmission electronic microscopy (TEM), particle size distribution (PSD), differential scanning calorimetry (DSC), and ultraviolet (UV)–visible (Vis). The new photocatalyst LT76 presents specific surface area of 0.791 m2/g and Curie temperature of 1197 °C. The photocatalytic efficiency of this material is assessed in terms of wastewater treatment and electricity generation by power density and removal rate of chemical oxygen demand (COD) in the presence of a light source. The values of maximum power density and COD removal were 19.77 mW/m3 and 93%, respectively, for LT76.


Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5552
Author(s):  
Ryota Kudo ◽  
Masahiro Sonobe ◽  
Yoshiaki Chino ◽  
Yu Kitazawa ◽  
Mutsumi Kimura

The synthesis and characterization of two phthalocyanine (Pc) structural isomers, 1 and 2, in which four 2,6-di(hexyloxy)phenyl units were attached directly to the 1,8,15,22- or 1,4,15,18-positions of the Pc rings, are described. Both Pcs 1 and 2 exhibited low melting points, i.e., 120 and 130 °C respectively, due to the reduction in intermolecular π-π interaction among the Pc rings caused by the steric hindrance of 2,6-dihexyloxybenzene units. The thermal behaviors were investigated with temperature-controlled polarizing optical microscopy, differential scanning calorimetry, powder X-ray diffraction, and absorption spectral analyses. Pc 1, having C4h molecular symmetry, organized into a lamellar structure containing lateral assemblies of Pc rings. In contrast, the other Pc 2 revealed the formation of metastable crystalline phases, including disordered stacks of Pcs due to rapid cooling from a melted liquid.


2000 ◽  
Vol 15 (7) ◽  
pp. 1617-1621 ◽  
Author(s):  
Jan Schroers ◽  
Konrad Samwer ◽  
Frigyes Szuecs ◽  
William L. Johnson

The reaction of the bulk glass forming alloy Zr41Ti14Cu12Ni10Be23 (Vit 1) with W, Ta, Mo, AlN, Al2O3, Si, graphite, and amorphous carbon was investigated. Vit 1 samples were melted and subsequently solidified after different processing times on discs of the different materials. Sessile drop examinations of the macroscopic wetting of Vit 1 on the discs as a function of temperature were carried out in situ with a digital optical camera. The reactions at the interfaces between the Vit 1 sample and the different disc materials were investigated with an electron microprobe. The structure and thermal stability of the processed Vit 1 samples were examined by x-ray diffraction and differential scanning calorimetry. The results are discussed in terms of possible applications for composite materials.


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