scholarly journals Synthesis and characterization of SmAlO3 by stearic acid route

2020 ◽  
Author(s):  
J.M. Li ◽  
Chuimin Zhang ◽  
Hui Liu ◽  
Tai Qiu ◽  
Chuangang Fan
Keyword(s):  
Electron Microscopy ◽  
Stearic Acid ◽  
Solid State Reaction Method ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
Microwave Ceramics ◽  
Conventional Solid State Reaction ◽  
Microwave Frequencies ◽  
Large Size ◽  
Ft Ir

Abstract A rapid and facile approach was developed for the synthesis of ultrafine SmAlO3 powders through the combustion of stearic acid precursors. The obtained products were characterized by typical techniques including X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and electron microscopy transmission (TEM) to analyze the phase composition and microstructure. The dielectric characteristics of SmAlO3 microwave ceramics, using the as-obtained products as original materials, were also studied. Compared with the conventional solid-state reaction method, the synthesis temperature was dramatically reduced to 750 ℃. The large-size sheet structure was composed of a number of micro/nano-scale crystallites, which were mostly irregular in shape due to the mutual growth and overlapping shapes of adjacent grains. The SmAlO3 ceramics with high density and uniform microstructure were obtained after sintering at 1500 ℃ for 4 h due to the favorable sintering activity of the as-synthesized powders. In addition, desired dielectric properties at microwave frequencies (dielectric constant εr = 20.22, quality factor Q·f = 74110 GHz, and a temperature coefficient of resonant frequency τf = -74.6 ppm/℃) were achieved.

scholarly journals Chemical synthesis of SmAlO3 by stearic acid route: structure, morphology and microwave dielectric properties

2020 ◽  
Author(s):  
J.M. Li ◽  
Chuimin Zhang ◽  
Hui Liu ◽  
Tai Qiu ◽  
Chuangang Fan
Keyword(s):  
Electron Microscopy ◽  
Dielectric Properties ◽  
Stearic Acid ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
Microwave Ceramics ◽  
Conventional Solid State Reaction ◽  
Microwave Frequencies

Abstract A rapid and facile approach was developed for the synthesis of ultrafine SmAlO3 powders through spontaneously combusting stearic acid precursors. The obtained products were characterized by typical techniques including X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM) and electron microscopy transmission (TEM) to analyze the phase composition and microstructure. The dielectric characteristics of SmAlO3 microwave ceramics using the as-obtained products as original materials were also studied. Comparing with conventional solid-state reaction method, the synthesis temperature was dramatically reduced to 750 °C. Large size sheet structure was composed of a number of micro/nano-scale crystallites that were almost irregular in shape due to the mutual growth and overlapped shape of adjacent grains. The SmAlO3 ceramics with high density and uniform microstructure were obtained after sintering at 1500 °C for 4 h due to good sintering activity of the as-synthesized powders. In addition, desired dielectric properties at microwave frequencies (dielectric constant εr = 20.22, quality factor Q·f = 74110 GHz, and temperature coefficient of resonant frequency TCf = -74.6 ppm/°C) were achieved.

scholarly journals Structure, morphology, and microwave dielectric properties of SmAlO3 synthesized by stearic acid route

2020 ◽  
Vol 9 (5) ◽  
pp. 558-566 ◽  
Author(s):  
Jiamao Li ◽  
Chuimin Zhang ◽  
Hui Liu ◽  
Tai Qiu ◽  
Chuangang Fan
Keyword(s):  
Electron Microscopy ◽  
Dielectric Properties ◽  
Stearic Acid ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Synthesis Temperature ◽  
Microwave Ceramics ◽  
Conventional Solid State Reaction ◽  
Microwave Frequencies ◽  
Transmission Electron

Abstract A rapid and facile approach was developed for the synthesis of ultrafine SmAlO3 powders through the combustion of stearic acid precursors. The obtained products were characterized by typical techniques including X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to analyze the phase composition and microstructure. The dielectric characteristics of SmAlO3 microwave ceramics, using the as-obtained products as original materials, were also studied. Compared with the conventional solid-state reaction method, the synthesis temperature was dramatically reduced to 750 °C. The large-size sheet structure was composed of a number of micro/nano-scale crystallites, which were mostly irregular in shape due to the mutual growth and overlapping shapes of adjacent grains. The SmAlO3 ceramics with high density and uniform microstructure were obtained after sintering at 1500 °C for 4 h due to the favorable sintering activity of the as-synthesized powders. In addition, desired dielectric properties at microwave frequencies (dielectric constant εr = 20.22, quality factor Q·f = 74110 GHz, and a temperature coefficient of resonant frequency τf = −74.6 ppm/°C) were achieved.

scholarly journals Hydrothermal Synthesis, Characterization and Exploration of Photocatalytic Activities of Polyoxometalate: Ni-CoWO4 Nanoparticles

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 456
Author(s):  
Fahad A. Alharthi ◽  
Hamdah S. Alanazi ◽  
Amjad Abdullah Alsyahi ◽  
Naushad Ahmad
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Photocatalytic Activities ◽  
Ft Ir ◽  
Photocatalytic Reactions ◽  
Cobalt Tungstate

This study demonstrated the hydrothermal synthesis of bimetallic nickel-cobalt tungstate nanostructures, Ni-CoWO4 (NCW-NPs), and their phase structure, morphology, porosity, and optical properties were examined using X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), high resolution Transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) and Raman instruments. It was found that as-calcined NCW-NPs have a monoclinic phase with crystal size ~50–60 nm and is mesoporous. It possessed smooth, spherical, and cubic shape microstructures with defined fringe distance (~0.342 nm). The photocatalytic degradation of methylene blue (MB) and rose bengal (RB) dye in the presence of NCW-NPs was evaluated, and about 49.85% of MB in 150 min and 92.28% of RB in 90 min degraded under visible light. In addition, based on the scavenger’s study, the mechanism for photocatalytic reactions is proposed.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

scholarly journals Investigations of M3Al8O15:Eu3+,Dy3+ (M = Ba, Ca, Mg) phosphors

2016 ◽  
Vol 34 (2) ◽  
pp. 412-417
Author(s):  
Esra Öztürk
Keyword(s):  
Electron Microscopy ◽  
Solid State Reaction Method ◽  
Morphological Characterization ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Three Samples ◽  
Scanning Electron ◽  
The Eu

AbstractIn this work, aluminate type phosphorescence materials were synthesized via the solid state reaction method and the photoluminescence (PL) properties, including excitation and emission bands, were investigated considering the effect of trace amounts of activator (Eu3+) and co-activator (Dy3+). The estimated thermal behavior of the samples at certain temperatures (> 1000 °C) during heat treatment was characterized by differential thermal analysis (DTA) and thermogravimetry (TG). The possible phase formation was characterized by X-ray diffraction (XRD). The morphological characterization of the samples was performed by scanning electron microscopy (SEM). The PL analysis of three samples showed maximum emission bands at around 610 nm, and additionally near 589 nm, 648 nm and 695 nm. The bands were attributed to typical transitions of the Eu3+ ions.

Study on Nano- and Microcrystallites in Urines of Uric Acid Stone Patients

2013 ◽  
Vol 655-657 ◽  
pp. 1927-1930 ◽  
Author(s):  
Guang Na Zhang ◽  
Zhi Yue Xia ◽  
Jian Ming Ouyang ◽  
Li Kuan
Keyword(s):  
Electron Microscopy ◽  
Uric Acid ◽  
X Ray Diffraction ◽  
Uric Acid Stone ◽  
Urine Ph ◽  
Stone Formers ◽  
Transmission Electron ◽  
Close Relationship ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The presence of crystallites in urine is closely related to stones formation. In this article, the components, morphology of nano- and micro-crystallites in urines of 20 uric acid (UA) stone formers as well as their relationship with the formation of UAstones were comparatively studied using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The main constituent of urinary crystallites was uric acid. Their particle size distribution was highly uneven, ranging from several nanometers to several tens of micrometers, and obvious aggregation was observed. These results showed that there was close relationship among stone components, urinary crystallites composition and urine pH.

scholarly journals A Novel Strong Cyan Luminescence Emission of Tb2O3 Particles

2021 ◽  
Author(s):  
Fatma Unal
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ammonium Carbonate ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Terbium Oxide ◽  
X Ray ◽  
Ft Ir ◽  
Pl Emission ◽  
Scanning Electron

Abstract Terbium oxide (Tb2O3) particles (NPs) were synthesized by precipitation method using ammonium carbonate as precipitation agent. Effects of precursor molarity (0.1, 0.15 and 0.2 M) on photoluminescence (PL) behaviour of the NPs were investigated. The presence of the Tb2O3 phase was confirmed by X-Ray Diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) analyses. Morphological investigations of the produced powders were made by Field Emission Gun-Scanning Electron Microscopy (FEG-SEM). It showed that the morphology of Tb2O3 particles transformed from the nanograin chain to bundles morphology of rod-like as the amount of precursor molarity increased. Emission spectrum were investigated by Photoluminescence (PL) Spectroscopy. All the Tb2O3 particles exhibited the strongest peak at 493 nm ascribed to 5D4-7F6 (magnetic dipole (MD), C2) transition. The increase in the number of C2 sites released from the MD transition with the increase of the precursor molarity caused a negative increase in the b* (yellowness/blueness of the emission) value in the CIE diagram, indicating that the colour shifted to the blue region. The Tb2O3 particles produced by the precipitation method exhibited novel strong cyan colour and the PL emission intensity increased with increasing molarity.

scholarly journals Pengaruh Suhu Sintering Terhadap Sintesis Silicon Carbide (SiC) Berbahan Dasar Abu Sekam Padi dan Grafit Pensil 2B

2015 ◽  
Vol 5 (01) ◽  
pp. 31
Author(s):  
Resky Irfanita ◽  
Asnaeni Ansar ◽  
Ayu Hardianti Pratiwi ◽  
Jasruddin J ◽  
Subaer S
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Rice Husk Ash ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Scanning Electron

The objective of this study is to investigate the effect of sintering temperature on the synthesis of SiC produced from rice husk ash (RHA) and 2B graphite pencils. The SiC was synthesized by using solid state reaction method sintered at temperatures of 750°C, 1000°C and 1200°C for 26 hours, 11.5 hours and 11.5 hours, respectively. The quantity and crystallinity level of SiC phase were measured by means of Rigaku MiniFlexII X-Ray Diffraction (XRD). The microstructure of SiC was examined by using Tescan Vega3SB Scanning Electron Microscopy (SEM). The XRD results showed that the concentration (wt%) of SiC phase increases with the increasing of sintering temperature. SEM results showed that the crystallinity level of SiC crystal is improving as the sintering temperature increases

scholarly journals Improving stability of cerium oxide nanoparticles by microbial polysaccharides coating

2018 ◽  
Vol 83 (6) ◽  
pp. 745-757 ◽  
Author(s):  
Ivana Milenkovic ◽  
Ksenija Radotic ◽  
Branko Matovic ◽  
Marija Prekajski ◽  
Ljiljana Zivkovic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cerium Oxide ◽  
Aqueous Media ◽  
Suspension Stability ◽  
X Ray Diffraction ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Ft Ir ◽  
Microbial Exopolysaccharides ◽  
The Stability

Cerium oxide (CeO2) nanoparticles (CONPs) are interesting biomaterials with various applications in biomedicine, cosmetics and the pharmaceutical industry, but with limited practical application because of their low stability in aqueous media. The aim of this study was to obtain CONPs with increased stability by coating the particles. Microbial exopolysaccharides (levan, pullulan) and glucose were used to prepare CONPs under different synthesis conditions. Coating was attempted by adding the carbohydrates during (direct coating) or after (subsequent coating) the synthesis of CONPs. The obtained nanoparticles were characterized by X-Ray diffraction analysis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The suspension stability of the uncoated and coated CONPs in aqueous media was evaluated by measuring the hydrodynamic size, zeta potential and turbidity. The FT-IR spectra revealed the differences between coated CONPs and showed the success of subsequent coating with carbohydrates. Coating with carbohydrates improved the stability the CONP suspension by decreasing the size of aggregated particles. The suspensions of levan- and glucose-coated CONPs had the best stability. In this study, CONPs were prepared using non-toxic materials, which were completely environmentally friendly. The obtained results open new horizons for CONP synthesis, improving their biological applications.

Synthesis of Indole Derivatives Using Biosynthesized ZnO-CaO Nanoparticles as an Efficient Catalyst

2021 ◽  
Vol 66 ◽  
pp. 61-71
Author(s):  
Tahereh Heidarzadeh ◽  
Navabeh Nami ◽  
Daryoush Zareyee
Keyword(s):  
Electron Microscopy ◽  
Indole Derivatives ◽  
X Ray Diffraction ◽  
Efficient Catalyst ◽  
X Ray ◽  
Transmission Electron ◽  
Solvent Free Conditions ◽  
Ft Ir ◽  
Eggshell Waste ◽  
Aromatic And Aliphatic Amines

The principal aim of this research is using biosynthesized ZnO-CaO nanoparticles (NPs) for preparation of indole derivatives. ZnO-CaO NPs have been prepared using Zn(CH3COO)2 and eggshell waste powder in solvent-free conditions. Morphology and structure of NPs were determined by FT-IR, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive spectra (EDS). It was used as a highly efficient catalyst for the synthesis of indole derivatives. Some indole derivatives were synthesized by the reaction of indole, formaldehyde, aromatic and aliphatic amines in the presence of ZnO-CaO NPs (5 mol%) in ethanol under reflux conditions. The assigned structure was further established by CHN analyses, NMR, and FT-IR spectra. Because of excellent capacity, the exceedingly simple workup and good yield, eco-friendly catalyst ZnO-CaO NPs were proved to be a good catalyst for this reaction.

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