scholarly journals Simple and Efficient Rout for Synthesis of Spinel Nanopigments

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Leila Torkian ◽  
Maryam Daghighi ◽  
Zahra Boorboor

Nano-sized CoxMg1−xAl2O4(x= 0, 0.1, 0.2, 0.4, 0.6, 0.8, and 1) inorganic pigments were synthesized via combustion method usingβ-alanine, as a single and novel fuel, at 800°C in open furnace. The obtained powders were characterized by means of X-ray diffraction (XRD), energy dispersive X-ray (EDX) elemental analysis, diffuse reflectance spectrum (DRS), CIEL*a*b* color measurements, and scanning electron microscope (SEM). XRD patterns show that all calcined powders have single phase cubic spinel structure. EDX analysis revealed the composition of desired spinels. The diffuse reflectance spectra of the CoxMg1−xAl2O4(x> 0) pigments confirmed the presence of tetrahedrally coordinated Co2+ions in the spinel lattice. The colorimetric data pointed out the formation of blue pigments (forx> 0), corresponding to highly negative values ofb*, and the bluest color was produced forx= 0.8 and 1. SEM images showed nanoparticles with less than 30 nm crystallite size and flakes-like appearance of all synthesized powders.

2020 ◽  
Vol 10 (03) ◽  
pp. 2050003
Author(s):  
M. R. Hassan ◽  
M. T. Islam ◽  
M. N. I. Khan

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.


2021 ◽  
Vol 12 (4) ◽  
pp. 2523-2529
Author(s):  
Daniel Sam N ◽  
Anish C I ◽  
Sabeena G ◽  
Rajaduraipandian S ◽  
Manobala ◽  
...  

Sol gel methods were used for the study of the antimicrobial activity of Cd-TiO2 against gram-negative and positive bacteria. These Cd-TiO2 have been characterized by various optical and techniques. They have been exhibited by X-ray diffraction, scanning electron microscopy, ultraviolet spectroscopy, and infrared spectroscopy. The structures of the various XRD patterns indicate that the product has a structure. The particle size of Cd-TiO2 is 35nm. The SEM images confirm the spherical appearance of the sample. The energy X-ray spectra have been confirmed as well and then C, O, Ti, Cd, Pt element are present in Cd-TiO2. The weight percentage of Cadmium is 5.8%, Ti is 51.03%, C is 5.13% and O is 31.75% in Cd-TiO2. BET image shows that the major pore size distribution of Cd-TiO2 is ranged from 2.24 nm. The Cd-TiO2 that the antibacterial activity when tested against the pathogens only gram-negative bacteria such as Pseudomonas. The zone of minimum inhibition concentration was measured in a range of 20mm in 25μl and 30mm in 100μl.


1998 ◽  
Vol 4 (S2) ◽  
pp. 342-343 ◽  
Author(s):  
S. D. Walck ◽  
P. Ruzakowski-Athey

The analysis of Selected Area Diffraction (SAD) patterns that are collected from a single phase material having sufficient crystallites to provide continuous rings is relatively straightforward. However, when this condition is not met and there may be several phases present having rings of a spotty nature, the pattern is complex and can be quite difficult to analyze manually because of the vast number of discrete spots. WinJade from MDI is an X-ray diffraction (XRD) analysis program with an Electron Diffraction Program Module (EDPM) that can be used to aid in the analysis of SAD patterns. The EDPM produces Integrated Circular Density Plots (ICDP), which are one-dimensional intensity profiles plotted as a function of equivalent XRD 20 values or crystal d-spacings. These ICDP's can be overlayed with XRD patterns or with reference lines from the NIST and JCPDS crystalline databases for direct comparisons.


2017 ◽  
Vol 751 ◽  
pp. 825-830 ◽  
Author(s):  
Phuri Kalnaowakul ◽  
Tonghathai Phairatana ◽  
Aphichart Rodchanarowan

In this study, the photocatalytic properties and morphology of TiO2, ZnO, Ag-graphene-zinc oxide (Ag-G-ZnO) and Ag-graphene-titanium dioxide (Ag-G-TiO2) nanocomposite were compared. The Ag-G-ZnO and Ag-G-TiO2 nanocomposite were successfully prepared by thermal decomposition of colloidal solution. These prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy and photocatalytic activities. The results from XRD patterns show that Ag-G-TiO2 composites and the Ag-G-ZnO nanocomposites were in the form of fcc and hcp crystal structure, respectively. The SEM images show that at calcination of 500 °C for 3 h, the composite thin film of Ag-G-ZnO and Ag-G-TiO2 were homogenous. In the case of the photocatalytic experiments using methylene blue dye (MB) under UV irradiation, the order of the photocatalytic activities from high to low performances are Ag-G-ZnO, Ag-G-TiO2, ZnO and TiO2, respectively.


2013 ◽  
Vol 860-863 ◽  
pp. 907-910
Author(s):  
Xiao Xia Lin ◽  
Jia Liu ◽  
De Gang Fu

B-doped TiO2nanotube arrays (B-TNTs) were synthesized by anodization method combined with dip-calcination technique. The physicochemical properties and surface morphology were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV-Vis diffuse reflectance spectrum (DRS). Methyl blue (MB) solution was utilized as the degradation model to evaluate the photocatalytic activity of B-TNTs under visible light irradiation. The results show B-TNTs shifts the absorption edge of TiO2nanotube arrays to the visible light region and B-TNTs displays higher photocatalytic activity compared with undoped TNTs.


2016 ◽  
Vol 16 (4) ◽  
pp. 3857-3860 ◽  
Author(s):  
Siling Guo ◽  
Chunyan Cao ◽  
Renping Cao

Through a hydrothermal method, 1 mol% Eu3+ doped NaYF4 and KYF4 micro/nanocrystals have been synthesized. The materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM) images, room temperature photoluminescence (PL) excitation and emission spectra, and luminescent dynamic decay curves. The XRD analysis suggested the crystalline structures of the obtained samples. The FE-SEM images indicated the morphology and size of the obtained samples. The PL spectra illustrate the optical properties of Eu3+ in the two samples. Since it is sensitive to the local environment of the ion, the Eu3+ presents different optical properties in the NaYF4 and KYF4 materials.


2016 ◽  
Vol 14 (1) ◽  
pp. 15 ◽  
Author(s):  
Maykel Manawan ◽  
Azwar Manaf ◽  
Bambang Soegijono ◽  
Asep Yudi Hercuadi

The effect of Ti2+-Mn4+substitution on microwave absorption has been studied for BaFe12-2xTixMnxO19 ferrite, where x varies from 0.2, 0.4, 0.6 and 0.8.Ti2+-Mn4+ ions were obtained from TiO and MnO2 precursors which were mechanically alloyed together with BaCO3 and Fe2O3 precursors. X-ray diffraction (XRD) patterns for sintered samples confirmed that the materials are consisted with single phase BHF structure. Unit cell volume and crystallite size was found increase with increasing x. Crystallite size for all samples below 70 nm, but the grain morphology shown that the grains is in range of 200 - 400 nm, which concluded that each grain are polycrystalline. The saturation magnetization is increases up to x = 0.4 and decrease for higher x values, while the coercivity remains decreases monotonically. These results were interpreted in terms of the site preferential occupation of Ti2+ and Mn4+ at low level substitution.These substitution revealed of enhanced reflection loss (RL) up to 25 dB forx=0.6.It suggested that the synthesized can be employed as effective microwave absorbers in various devices.


2021 ◽  
Vol 406 ◽  
pp. 219-228
Author(s):  
Ouahiba Herzallah ◽  
Hachemi Ben Temam ◽  
Asma Ababsa ◽  
Abderrahmane Gana

Ni–Co alloy coatings were electrodeposited at various cobalt amounts on pretreated steel substrates. The co-deposition phenomenon of Ni-Co alloys was described as anomalous behaviour. Different techniques including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), X-ray diffraction (XRD) and potentiodynamic polarization were used to characterize the alloy coatings. EDX results showed that the Co content increase with the enhancing of Co amount. SEM images have shown that the increase of Co amount leads grain developing from large grain to branched grain form and that goes through spherical and pyramidal, this implies that the grain size of these alloy coatings is greatly affected by Co amount in the electrolyte baths. XRD patterns revealed that the phase structure of Ni–Co coatings is dramatically changed from fcc into hcp structure with the increase of Co amount. The electrochemical properties of Ni-Co alloy coatings evaluated in 3.5% NaCl solution reveal that Ni–34.32 wt.% Co alloy exhibits better corrosion resistance compared to pure Ni and other Ni–Co alloy coatings.


2015 ◽  
Vol 29 (14) ◽  
pp. 1550090 ◽  
Author(s):  
O. Mirzaee ◽  
R. Mohamady ◽  
A. Ghasemi ◽  
Y. Alizad Farzin

Nanostructure of Y-type hexaferrite with composition of Sr 2 Ni 2 Al x/2 Cr x/2 Fe 12-x O 22 (where x are 0, 0.6, 1.2, 1.8, 2.4 and 3) were prepared by sol–gel auto-combustion method. The influence of Al and Cr doping on the structural and magnetic properties has been investigated. The X-ray diffraction (XRD) patterns confirm phase formation of Y-type hexaferrite. The microstructure and morphology of prepared samples were studied by high resolution field emission scanning electron microscope (FESEM) which shows the hexagonal shape for all of the samples. Magnetic properties were characterized using vibrating sample magnetometer (VSM). The magnetic results revealed that by increasing the Al and Cr to the structure, the coercivity was also increased from 840 Oe to 1160 Oe. Moreover it has been shown that with addition of dopants, saturation magnetization (Ms) and remnant magnetization (Mr) were decreased from 39.61 emu/g to 30.11 emu/g and from 17.51 emu/g to 14.62 emu/g, respectively, due to the entrance of nonmagnetic ions into Fe 3+ sites.


2011 ◽  
Vol 197-198 ◽  
pp. 405-408
Author(s):  
Shao Teng Yan ◽  
Xiao Gu Huang ◽  
Feng Dai ◽  
Peng De Han ◽  
Li Xi Wang ◽  
...  

Perovskite type ferrite doped with Sr2+, Dy1-xMxFeO3(x = 0.0, 0.05, 0.15, 0.25) were prepared by the conventional solid-state reaction. The structure and electromagnetic properties of the calcined samples were studied using powder X-ray diffraction (XRD, Rigaku D/Max-2500) and network analyzer (Agilent 8722ET). All the XRD patterns showed the single phase of the perovskite type ferrite without other intermediate phase when x≤0.25. The electromagnetic properties of the samples have been studied at the frequency range from 2 GHz to 18 GHz. The ε′ and ε′′ values were improved significantly. Both the values of ε′ and ε′′ increase with the increasing content of the doped cations Sr2+, and the peak value of ε′′ was about 2.2 at 12.1 GHz position when x = 0.25.


Sign in / Sign up

Export Citation Format

Share Document