scholarly journals Synthesis and application of pigments based on lanthanide orthoferrites

2020 ◽  
Vol 14 (2) ◽  
pp. 161-167
Author(s):  
Patrícia Pimentel ◽  
Jairo Dutra ◽  
Maria Câmara ◽  
Gerbeson Dantas ◽  
Osmar Bagnato ◽  
...  

In this work, we synthesized oxides with perovskite LnFeO3 type structure (where Ln = La, Pr and Nd), aiming their use as ceramic pigments. The as-synthesized powders, prepared by gelatin method, were thermally treated at 600 and 800 ?C to obtain the perovskite phase. The characterization was performed using X-ray diffraction technique, followed by Rietveld refinement, scanning and transmission electron microscopy, spectroscopy in the UV-Visible region and CIE Lab colorimetry. The calcined powders were also used for fabrication of ceramic pieces to evaluate the colour when 2 wt.% of the powders was added into a transparent glaze. The pigments presented shades ranging from pale brown for the powdered samples to yellowish when applied in the glazes.

RSC Advances ◽  
2014 ◽  
Vol 4 (59) ◽  
pp. 31155-31161 ◽  
Author(s):  
Young In Choi ◽  
Youngku Sohn

Eu(iii) and Tb(iv) activators were embedded in quantum size SnO2 nanoparticles by a hydrothermal method and their morphologies, crystal structures and spectroscopic properties were examined by transmission electron microscopy, X-ray diffraction crystallography, UV-visible absorption, and 2D/3D-photoluminescence mapping.


Author(s):  
R. Gronsky

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.


Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.


Author(s):  
Eric O'Quinn ◽  
Cameron Tracy ◽  
William F. Cureton ◽  
Ritesh Sachan ◽  
Joerg C. Neuefeind ◽  
...  

Er2Sn2O7 pyrochlore was irradiated with swift heavy Au ions (2.2 GeV), and the induced structural modifications were systematically examined using complementary characterization techniques including transmission electron microscopy (TEM), X-ray diffraction...


1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1712
Author(s):  
Appusamy Muthukrishnaraj ◽  
Salma Ahmed Al-Zahrani ◽  
Ahmed Al Otaibi ◽  
Semmedu Selvaraj Kalaivani ◽  
Ayyar Manikandan ◽  
...  

Towards the utilization of Cu2O nanomaterial for the degradation of industrial dye pollutants such as methylene blue and methyl orange, the graphene-incorporated Cu2O nanocomposites (GCC) were developed via a precipitation method. Using Hummers method, the grapheme oxide (GO) was initially synthesized. The varying weight percentages (1–4 wt %) of GO was incorporated along with the precipitation of Cu2O catalyst. Various characterization techniques such as Fourier-transform infra-red (FT-IR), X-ray diffraction (XRD), UV–visible diffused reflectance (UV-DRS), Raman spectroscopy, thermo gravimetric analysis (TGA), energy-dispersive X-ray analysis (EDX), and electro chemical impedance (EIS) were followed for characterization. The cabbage-like morphology of the developed Cu2O and its composites were ascertained from field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, the growth mechanism was also proposed. The results infer that 2 wt % GO-incorporated Cu2O composites shows the highest value of degradation efficiency (97.9% and 96.1%) for MB and MO at 160 and 220 min, respectively. Further, its catalytic performance over visible region (red shift) was also enhanced to an appreciable extent, when compared with that of other samples.


2012 ◽  
Vol 174-177 ◽  
pp. 508-511
Author(s):  
Lin Lin Yang ◽  
Yong Gang Wang ◽  
Yu Jiang Wang ◽  
Xiao Feng Wang

BiFeO3 polyhedrons had been successfully synthesized via a hydrothermal method. The as-prepared products were characterized by power X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The possible mechanisms for the formation of BiFeO3 polyhedrons were discussed. Though comparison experiments, it was found that the kind of precursor played a key role on the morphology control of BiFeO3 crystals.


2007 ◽  
Vol 353-358 ◽  
pp. 2163-2166
Author(s):  
Ming Yang ◽  
Guo Qing Zhou ◽  
Jiang Guo Zhao ◽  
Zhan Jun Li

Nanocubes, monodispersed nanocrystals and nanospheres of Au have been prepared by a simple reaction between HAuCl4·4H2O, NaOH and NH2OH·HCl in the presence of gelatin. The role of gelatin and the affection of pH in producing the nanoparticles of Au were discussed. The products were characterized by X-ray powder diffraction, transmission electron microscopy, and UV-visible absorption spectroscopy. The sizes of the monodispersed nanocrystals of Au were estimated by Debye-Scherrer formula according to XRD spectrum.


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