Chemical synthesis and densification of a novel Ag/Cr2O3-AgCrO2 nanocomposite powder

2018 ◽  
Vol 25 (4) ◽  
pp. 739-743 ◽  
Author(s):  
Mohammad Ardestani ◽  
Farshid Karpasand
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Synthesis Method ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Nanocomposite Powder ◽  
Dense Microstructure ◽  
Air Atmosphere ◽  
Nanocomposite Powders ◽  
Scanning Electron

Abstract Ag/Cr2O3-AgCrO2 nanocomposite powders were chemically synthesized using a chemical precipitation method. The synthesis method stages included precipitation and calcination. The initial precipitates contained Cr(OH)3·3H2O and Ag2CO3 compounds. Calcination of the initial precipitates led to thermal decomposition of the precipitates and evaporation of volatile compounds such as H2O and CO2. The calcined precipitates contained silver, chromium oxide, and silver-chromia. The crystallite size of Ag2CO3 and Ag were determined as 18.9 and 45 nm, respectively. The scanning electron microscopy investigations showed that the particle size of the initial precipitates was lower than 100 nm. The calcined powders were sintered at 550°C in air atmosphere. The sintered samples were cold-repressed under 300 and 550 MPa. It was found that by increasing the repressing compaction magnitudes, the density and hardness of the sintered samples were increased. The scanning electron microscopy evaluation of the densified samples showed nearly dense microstructure.

scholarly journals Pengaruh Perbandingan Mol Awal Titanium dan Perak terhadap Sifat-Sifat Fisika-Kimia TiO2-tersensitifkan AgCl

2017 ◽  
pp. 106-115
Author(s):  
Isnaya Khamida Zulfah ◽  
Hari Sutrisno
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Diffuse Reflectance ◽  
Silver Chloride ◽  
Ultra Violet ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray ◽  
Initial Comparison ◽  
Scanning Electron

Titanium dioksida (TiO2)merupakan semikonduktor yang memiliki fungsi sebagai fotokatalis, sel surya, anti bakteri, anti polutan, dan anti buram. Salah satu cara untuk meningkatkan aktifitas fungsional  TiO2dengan menggeser daerah aktifitas atau energi celah pita (Eg) dari sinar ultra violet (UV) ke daerah sinar tampak melalui penambahan zat pensensitif TiO2.Pada penelitian ini, perak klorida (AgCl) digunakan sebagai zat pensensitif TiO2. Tujuan penelitian ini untuk mengetahui pengaruh variasi perbandingan mol awal [Ti8O12(H2O)24]8.Cl8.HCl.7H2O dengan AgNO3 terhadap sifat-sifat fisik TiO2 tersensitifkan AgCl (TiO2@AgCl) yang disintesis dengan metode pengendapan basah dalam suasana asam. Variasi perbandingan awal yang digunakan yaitu perbandingan mol [Ti8O12(H2O)24]8.Cl8.HCl.7H2O :mol AgNO3sebesar 1:9, 1:10, 1:11, 1:12, dan 1:13yang dilarutkan dalam pelarut etanol (total pelarut 37.5 mL). Sampel padat TiO2@AgCl dihasilkan dengan metode pengendapan basah dalam kondisi asam melalui pengontrolan asam HNO3 pada pH~1. Sampel dihasilkan dari penguapan filtrat yang  bebas dari endapan AgCl, hingga volume yang didapat setengah dari volume awal. Sampel TiO2@AgCl dikarakterisasi dengan berbagai instrumen: Difraktometer Sinar-X (XRD),Scanning Electron Microscopy-Electron Dispersive X-Ray Analyzer (SEM-EDAX), dan Spektrofotometer UV-Vis Diffuse Reflectance. Hasil penelitian menunjukkan semua sampel TiO2@AgCl berisi 1 fasa nanopartikel (nanokristalit) TiO2 dan 3 fasa kristal yaitu rutil, anatas, dan AgCl.TiO2@AgCl memiliki bentuk morfologi berupa mikrosferik dengan ukuran berkisar 0.5-1 μm. Berdasarkan hasil analisisdengan spektrofotometer UV-Vis Diffuse Reflectance menunjukkan semua sampel TiO2@AgCl mengabsorbsi sinar ultra violet (UV) dengan Eg sebesar 2.87-3.89 eV, dan sinar tampak dengan Eg sebesar 1.60-2.40 eV. Titanium dioxide (TiO2) is a semiconductor that can be applied in the field of photocatalyst, solar cell, anti-bacterial, anti-pollutants, and anti-fogging. The functional activity of TiO2 can be increased by shifting the activity area from ultraviolet (UV) to visible through the addition of sensitizer. In this research, silver chloride (AgCl) was used as a sensitizer The objective of the research is to study the effect of the initial mole comparison of [Ti8O12(H2O)24]8.Cl8.HCl.7H2O and AgNO3on the physical properties of AgCl-sensitized TiO2(TiO2@AgCl). All TiO2@AgCl were synthesized using the wet chemical precipitation method under acidic conditions by the addition of a concentrated HNO3 with pH ~ 1. The initial comparison variation used was the mole ratio of [Ti8O12(H2O)24]8.Cl8.HCl.7H2O  : AgNO3 of 1: 9, 1:10, 1:11, 1:12, and 1:13. Each of these materials was dissolved in ethanol to 37.5 ml. All samples were produced from evaporation of filtrate free from AgCl precipitate, until the volume obtained half of the initial volume. The solid samples were characterized using X-Ray Diffractometer (XRD), Scanning Electron Microscopy-Electron Dispersive X-Ray Analyzer (SEM-EDAX), and UV-Vis spectrophotometer Diffuse Reflectance.The results showed that all samples of TiO2@AgCl consisted of 1 phase of TiO2-nanoparticles and 3 phases of rutile, anatase and AgCl crystals. The morphology of TiO2@AgCl is microspheric with a size ranging from 0.5-1 μm. Based on the results of the analysis with the UV-Vis spectrophotometer Diffuse Reflectance showed that all samples of TiO2@AgCl absorb ultraviolet (UV) rays with bandgap (Eg) ranging from 2.87 to 3.89 eV, and the visible light with Eg ranges from 1.60 to 2.40 eV.

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 Структура и механизмы образования наноразмерных пленок примесного металла кобальта и никеля в монокристаллах LiF и MgF-=SUB=-2-=/SUB=-

2021 ◽  
Vol 63 (9) ◽  
pp. 1340
Author(s):  
Н.А. Иванов ◽  
С.А. Небогин ◽  
С.С. Колесников ◽  
Л.И. Брюквина
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Etch Pits ◽  
Force Microscopy ◽  
Thermal Etching ◽  
Air Atmosphere ◽  
Atomic Force ◽  
Residual Air ◽  
Scanning Electron ◽  
Cobalt And Nickel

It is investigated the thermal etching of LiF and MgF2 crystals with cobalt and nickel impurities by means of scanning electron microscopy and atomic force microscopy with using decorating. It is shown that impurity inclusions leave the crystal from dislocations. The differences between of thermal etching in vacuum and air atmosphere take place. The crystallographic oriented terraced etch pits are formed after exit of impurities from dislocations. The square thermal etch pits are formed after thermal etching at 750°C in air. The surface impurity nanoscale film is formed at thermal etching. The oxidation of surface impurities observed at thermal etching in air atmosphere or in residual air atmosphere.

Synthesis and Characterization of Al2O3 by Using a Combustion Synthesis Method

2012 ◽  
Vol 545 ◽  
pp. 169-171 ◽  
Author(s):  
Mawar Hazwani Jasimin ◽  
Nurhanna Badar ◽  
Rusdi Roshidah ◽  
Norlida Kamarulzaman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Metal Oxides ◽  
Annealing Temperature ◽  
Synthesis Method ◽  
Combustion Method ◽  
Synthesis And Characterization ◽  
Size And Morphology ◽  
Scanning Electron

Aluminium oxide is one of the metal oxides that can exist in many phases such as α, θ, η etc. All the phases obtained are affected by annealing temperature and synthesis route. In this research the Al2O3 powders were synthesized by the combustion method using triethanolamine as fuels. A pure η phase as well as a mixed α and η phases were obtained. The size and morphology of Al2O3 particles were studied using scanning electron microscopy (SEM).

Synthesis of TiNi Particles in High Temperature Molten Salts

2005 ◽  
Vol 475-479 ◽  
pp. 1941-1944
Author(s):  
Rui Song Yang ◽  
Li Shan Cui ◽  
Yan Jun Zheng ◽  
Jin Long Zhao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
High Temperature ◽  
Molten Salts ◽  
Synthesis Method ◽  
Backscatter Electron ◽  
Scanning Calorimetry ◽  
Electron Image ◽  
Scanning Electron

. NiTi particles were prepared by the reaction between Ti and Ni powders in high temperature molten salts. Results of differential scanning calorimetry (DSC) confirmed the martensitic transformation of the prepared NiTi particles. Backscatter electron image of scanning electron microscopy (SEM) showed that the synthesized NiTi particles were captured by the molten salts, which revealed the mechanism of the chemical synthesis method in molten salts.

scholarly journals The influence of mechanical activation on sintering process of BaCO3-SrCO3-TiO2 system

2012 ◽  
Vol 44 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Darko Kosanovic ◽  
N. Obradovic ◽  
J. Zivojinovic ◽  
A. Maricic ◽  
V.P. Pavlovic ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Activation ◽  
Ball Mill ◽  
Sintering Process ◽  
Electrical Measurements ◽  
Air Atmosphere ◽  
Titanate Ceramics ◽  
Scanning Electron

In this article the influence of mechanical activation on sintering process of bariumstrontium-titanate ceramics has been investigated. Both non-activated and mixtures treated in a planetary ball mill for 5, 10, 20, 40, 80 and 120 minutes were sintered at 1100-1400?C for 2 hours in presence of air atmosphere. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100?C was too low to induce final sintering stage for this system. Electrical measurements have been conducted for the densest ceramics sintered at 1400?C for 2 hours.

scholarly journals Effect of Zinc Oxide on the Efficiency Enhancement of Al/Li2O/PSi/Si/Al solar cell

2021 ◽  
Author(s):  
Shahlaa M. Abd Al-Hussan ◽  
Nabeel A. Bakr ◽  
Ahmed N. Abd
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Zinc Oxide ◽  
Porous Silicon ◽  
Lithium Oxide ◽  
Precipitation Method ◽  
Oxide Nanoparticles ◽  
Casting Method ◽  
P Type ◽  
Scanning Electron

Abstract In this paper, electrochemical etching of the p-type silicon wafer is used to prepare p-type porous silicon with current density of 10 mA.cm− 2 for 10 minutes. Field Emission Scanning Electron Microscopy (FESEM) has been used to study porous silicon layer surface morphology. Zinc oxide and lithium oxide nanoparticles are prepared separately by chemical precipitation method and simple precipitation method, respectively and deposited on glass substrates by drop casting method. Moreover,, the structural properties of the films were analyzed by using XRD and SEM. The XRD results showed that the ZnO and Li2O films are polycrystalline with hexagonal wurtzite structure and cubic structure, and preferred orientation along (101) and (003) planes, respectively. Using Scherrer's formula, the crystallite size was measured and it was found that ZnO and Li2O thin films have a crystallite size of 22.04 and 45.6 nm respectively. Surface topography of the prepared thin films is studied by using Scanning Electron Microscopy (SEM). Later, certain proportions of both materials were mixed and deposited on porous silicon using drop casting method at thickness of 1.4 µm. After that, the characteristics of the solar cell were investigated. Mixing zinc oxide nanoparticles in particular proportions with lithium oxide played a major role in increasing the solar cell's performance. The highest prepared film efficiency was obtained at mixing ratio (0.5: 0.5) for (ZnO: Li2O) and its value was (11.09 %).

scholarly journals Influence of Processing Type in the Morphology of Membranes Obtained from PA6/MMT Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Rodholfo da Silva Barbosa Ferreira ◽  
Caio Henrique do Ó Pereira ◽  
Rene Anisio da Paz ◽  
Amanda Melissa Damião Leite ◽  
Edcleide Maria Araújo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Screw Extruder ◽  
X Ray ◽  
Membrane Morphology ◽  
Twin Screw ◽  
Microscopy Images ◽  
Scanning Electron

The nanocomposites have an extensive use in the current process of membrane preparation, taking into account their unique features as membranes. Thus, the study of nanocomposite processing to obtain membranes is highly important. In this work, Brazilian clay was used (Brasgel PA) for the preparation of polyamide/clay nanocomposite. The nanocomposites were produced in a high rotation homogenizer and in a twin screw extruder. From the nanocomposites and pure polymers processed in the two equipments, membranes were prepared by the immersion-precipitation method, using formic acid as solvent. By X-ray diffraction (XRD), the formation of exfoliated and/or partially exfoliated structures with changes in the crystalline phases of the polyamide was observed. From scanning electron microscopy images, it was observed that the processing clearly influenced the membrane morphology.

Carbothermal Synthesis of Cr3C2-WC-Ni Nanocomposite Powders

2013 ◽  
Vol 661 ◽  
pp. 3-6 ◽  
Author(s):  
Yong Zhong Jin ◽  
Fa Ming Ye ◽  
Xian Guang Zeng ◽  
Rui Song Yang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Carbothermal Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbothermal Synthesis ◽  
Unit Cells ◽  
Nanocomposite Powders ◽  
Scanning Electron

Cr3C2-WC-Ni nanocomposite powders with ~50-100 nm were synthesized from precursors by vacuum-aided carbothermal reduction at only 750 °C for 2 h. The phase composition and microstructure of the synthesized products were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The present study shows that Cr3C2-WC-Ni nanocomposite powders contain two kinds of solid-solution phases, namely Ni and (Cr, W)3C2solid solution, respectively. WC and W2C phases do not appear inreaction products due to the dissolution of tungsten atoms into Ni and Cr3C2unit cells. Especially, there is a change of the crystalline structure for (Cr, W)3C2phase from 750 °C to 800 °C.

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