scholarly journals Study of the Synthesis of Zirconia Powder from Zircon Sand obtained from Zircon Minerals Malaysia by Caustic Fusion Method

2020 ◽  
Vol 20 (4) ◽  
pp. 782
Author(s):  
Istikamah Subuki ◽  
Mimi Fazzlinda Mohsin ◽  
Muhammad Hussain Ismail ◽  
Fazira Suriani Mohamed Fadzil
Keyword(s):  
Fusion Method ◽  
X Ray Diffraction ◽  
Zirconia Powder ◽  
X Ray ◽  
Calcination Temperatures ◽  
Surface Areas ◽  
Pure Premium ◽  
Zircon Powder ◽  
Zircon Sand ◽  
Zirconia Powders

The zircon powder from Zircon Minerals Malaysia is a pure premium grade zircon sand milled 1.5 µm that contain ZrSiO4, ZrO2, HfO2, SiO2, Al2O3, TiO2, and Fe2O3. The monoclinic zirconia powders were synthesized from the zircon sand of Zircon Minerals Malaysia, by caustic fusion method at calcination temperatures between 500 °C to 800 °C. The as-synthesized zirconia was characterized through X-Ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTA), and X-Ray fluorescence (XRF) techniques. The XRD results show two monoclinic phases of microcrystalline zirconia. Zirconia that was calcined at 600 °C obtained the highest value of ZrO2, which was 54.48%; followed by zirconia calcined at 700 °C, 800 °C, and 500 °C, which obtained the ZrO2 values of 53.58%, 52.41%, and 51.53%, respectively, based on the XRF analysis. As-synthesized zirconia showed monoclinic phases where the surface areas were 0.0635 m2/g, 0.135 m2/g, 0.0268 m2/g, and 0.0288 m2/g, for zirconia calcined at temperatures of 500 °C, 600 °C, 700 °C, and 800 °C, respectively. The surface structure of the powder that had been calcined at 600 C showed similarities with the commercial zirconia. The similarities of the synthesized zirconia and commercial zirconia showed that the zirconia powder could be synthesized using zircon sand by caustic fusion method, even though the content of zirconia was lower compared to that of the commercial zirconia powder.

Effect of Particle Size of ZrO2(Y2O3) Powders on the Shrinkage of the Sintered Substrate with Coloring Gradient

2014 ◽  
Vol 87 ◽  
pp. 162-168
Author(s):  
Paula Cipriano da Silva ◽  
Roberto de Oliveira Magnago ◽  
Camila Aparecida Araujo da Silva ◽  
Bianca de Almeida Fortes ◽  
Claudinei dos Santos
Keyword(s):  
White Layer ◽  
Linear Shrinkage ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Particles Size Distribution ◽  
Cad Cam ◽  
Effect Of Particle Size ◽  
Cam Systems ◽  
Zirconia Powders

ZrO2(Y2O3)-based ceramics with coloring gradient can facilitate the development of dental prosthesis by the improvement of esthetic properties. In this work, ZrO2 powders with different particle sizes were investigated. White and yellow zirconia powders (TOSOH Corporation-Japan) were characterized by particles size distribution using nanoSight-LM20 analyzer. Furthermore, samples were characterized by X-Ray diffraction, Scanning Electron Microscopy and relative density. Compacts with two layers, one white and one yellow were uniaxially pressed at 80MPa and sintered at 1530°C-120min. The yellow-powder presented average particles size of 180±66nm, while the white-powder presented particles size of 198±73nm. After sintering, full dense ceramics with tetragonal phase were obtained. The linear shrinkage of the yellow and white-layer was 22.75% and 22.05% respectively. This difference in shrinkage is important in the machining of prostheses in ceramic CAD/CAM systems, because they lead to difficulties in adapting this customized prosthesis in patients.

scholarly journals Microporous Materials Based on Norbornadiene-Based Cross-Linked Polymers

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1382 ◽  
Author(s):  
Dmitry Alentiev ◽  
Dariya Dzhaparidze ◽  
Natalia Gavrilova ◽  
Victor Shantarovich ◽  
Elena Kiseleva ◽  
...  
Keyword(s):  
Pore Volume ◽  
Total Pore Volume ◽  
Amorphous Polymers ◽  
Co2 Uptake ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Pd Catalysts ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Surface Areas

New microporous homopolymers were readily prepared from norbornadiene-2,5, its dimer and trimer by addition (vinyl) polymerization of the corresponding monomers with 60–98% yields. As a catalyst Pd-N-heterocyclic carbene complex or Ni(II) 2-ethylhexanoate activated with Na+[B(3,5-(CF3)2C6H3)4]− or methylaluminoxane was used. The synthesized polynorbornenes are cross-linked and insoluble. They are glassy and amorphous polymers. Depending on the nature of the catalyst applied, BET surface areas were in the range of 420–970 m2/g. The polymers with the highest surface area were obtained in the presence of Pd-catalysts from the trimer of norbornadiene-2,5. The total pore volume of the polymers varies from 0.39 to 0.79 cm3/g, while the true volume of micropores was 0.14–0.16 cm3/g according to t-plot. These polymers gave CO2 uptake from 1.2 to 1.9 mmol/g at 273 K and 1 atm. The porous structure of new polymers was also studied by means of wide-angle X-ray diffraction and positron annihilation lifetime spectroscopy.

Structural and surface aspects of thermally treated copper aluminium mixed hydroxides

1991 ◽  
Vol 69 (10) ◽  
pp. 1511-1515 ◽  
Author(s):  
Awad I. Ahmed ◽  
S. E. Samra ◽  
S. A. El-Hakam
Keyword(s):  
Pore Structure ◽  
Copper Content ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Structure Surface ◽  
Adsorption Desorption

CuO–Al2O3 catalysts containing various amounts of copper oxide have been prepared by precipitation. The phase changes were studied by X-ray diffraction. The results obtained revealed that the thermal treatment of solid CuO–Al2O3 at 700 °C produced only crystalline CuO. Heating to 900 °C led to the formation of copper alumina spinel together with unreacted CuO and γ-Al2O3. The spinel content was found to increase with increasing copper content. Nitrogen adsorption–desorption isotherms on the calcined samples have been measured. Surface areas have been calculated and the pore structure analysed. The textural properties of the system were found to depend on both the copper content and the calcination temperature. Key words: CuO, Al2O3 catalysts, structure, surface area, pore structure.

Drop Solution Calorimetric Studies of Interface Enthalpy of Cubic Silver (I) Oxide (Ag2O) Nanocrystals

2021 ◽  
Vol 878 ◽  
pp. 73-80
Author(s):  
Khansaa Al-Essa ◽  
A V Radha ◽  
Alexandra Navrotsky
Keyword(s):  
Thermodynamic Cycle ◽  
Solution Calorimetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Chemical Technique ◽  
Crystallite Sizes ◽  
Wet Chemical ◽  
Wet Chemical Technique ◽  
Calorimetric Studies

The nanoscale, cubic silver (I) oxide (Ag2O.nH2O) with different particles sizes and surface areas were synthesized by a wet chemical technique. The prepared crystallite size ranges were from (33.3±0.3 to 39.4±0.4 nm). Interface areas were estimated by comparing the surface areas measured by N2 adsorption to the crystallite sizes refined from X-ray diffraction data. The interface enthalpy of Ag2O.nH2O nanocrystal was measured using isothermal acid solution calorimetry in 25%HNO3 at 26°C. The interface enthalpy was verified by utilizing thermodynamic cycle. The enthalpies of drop solution (ΔHds) for Ag2O.nH2O are exothermic and range from (-62.228±0.197) to (-64.025±0.434 kJ/mol), while its interface enthalpy is (0.842±0.508 J/m2). This work provides the first calorimetric measurement of the interface enthalpy of nanocrystalline silver (I) oxide (Ag2O.nH2O).

scholarly journals Low-Cost Synthesis of Cu-Modified Immobilized Nanoporous TiO2 for Photocatalytic Degradation of 1H-Benzotriazole

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 19 ◽  
Author(s):  
Tihana Čižmar ◽  
Ivana Panžić ◽  
Krešimir Salamon ◽  
Ivana Grčić ◽  
Lucija Radetić ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Spin Coating ◽  
Low Cost ◽  
Electrochemical Anodization ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Titanium Foils ◽  
The Given

Cu-modified immobilized nanoporous TiO2 photocatalysts, prepared by electrochemical anodization of titanium foils, were obtained via four different synthesis methods: hydrothermal synthesis, anodization with Cu source, electrodeposition, and spin-coating, using two different copper sources, Cu(NO3)2 and Cu(acac)2. The objective of this research was to investigate how copper modifications can improve the photocatalytic activity of immobilized nanoporous TiO2 under the UV/solar light irradiation. The best photocatalytic performances were obtained for Cu-modifications using spin-coating. Therefore, the effect of irradiated catalyst surface areas on the adsorption of model pollutants, methylene blue (MB) and 1H-benzotriazole (BT), was examined for samples with Cu-modification by the spin-coating technique. The mechanisms responsible for increased degradation of MB and BT at high Cu concentrations (0.25 M and 0.5 M) and decreased degradation at low Cu loadings (0.0625 M and 0.125 M) were explained. 1H-benzotriazole was used to study the photocatalytic activity of the given samples because it is highly toxic and present in most water systems. The characterization of the synthesized Cu-modified photocatalysts in terms of phase composition, crystal structure, and morphology were investigated using X-ray Diffraction, Raman Spectroscopy, Scanning Electron Microscopy, and Energy Dispersive X-ray spectroscopy.

Characterization of Cubic Ceria—Zirconia Powders by X-Ray Diffraction and Vibrational and Electronic Spectroscopy.

ChemInform ◽  
2004 ◽  
Vol 35 (6) ◽  
Author(s):  
Vicente Sanchez Escribano ◽  
Enrique Fernandez Lopez ◽  
Marta Panizza ◽  
Carlo Resini ◽  
Jose Manuel Gallardo Amores ◽  
...  
Keyword(s):  
Electronic Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconia Powders

scholarly journals Effects of Calcination Temperatures on Photocatalytic Activity of Ordered Titanate Nanoribbon/SnO2Films Fabricated during an EPD Process

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Li Zhao ◽  
Jingrun Ran ◽  
Zhan Shu ◽  
Guotian Dai ◽  
Pengcheng Zhai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Transformation ◽  
Photocatalytic Activity ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcination Temperatures ◽  
Fto Glass ◽  
Scanning Electron

Ordered titanate nanoribbon (TNR)/SnO2films were fabricated by electrophoretic deposition (EPD) process using hydrothermally prepared titanate nanoribbon as a precursor. The formation mechanism of ordered TNR film on the fluorine-doped SnO2coated (FTO) glass was investigated by scanning electron microscopy (SEM). The effects of calcination temperatures on the phase structure and photocatalytic activity of ordered TNR/SnO2films were investigated and discussed. The X-ray diffraction (XRD) results indicate that the phase transformation of titanate to anatase occurs at 400°C and with increasing calcination temperature, the crystallization of anatase increases. At 600°C, the nanoribbon morphology still hold and the TiO2/SnO2film exhibits the highest photocatalytic activity due to the good crystallization, unique morphology, and efficient photogenerated charge carriers separation and transfer at the interface of TiO2and SnO2.

scholarly journals Evaluation of Weld Filler Alloying Concepts for Residual Stress Engineering by Means of Neutron and X-Ray Diffraction

2014 ◽  
Vol 996 ◽  
pp. 469-474 ◽  
Author(s):  
Arne Kromm
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Reduction ◽  
Maximum Stress ◽  
Lattice Parameter ◽  
Filler Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stress Control ◽  
Surface Areas

Novel Low Transformation Temperature (LTT-) filler materials are specially designed for controlling residual stresses by means of adjusted martensite formation already during welding. Different alloying concepts compete for maximum stress reduction. Two newly developed LTT-alloys were evaluated concerning their potential for residual stress control. For this purpose residual stresses were determined in the surface and also in sub-surface areas of welded joints using X-ray diffraction and Neutron diffraction taking into account local variations of the unstrained lattice parameter.

scholarly journals Cu(II) and Cd(II) coordination polymers derived from pyrazine-2,3-dicarboxylato and 1-vinylimidazole ligands: Synthesis, characterization and hydrogen storage capacities

2019 ◽  
Vol 38 (1) ◽  
pp. 19 ◽  
Author(s):  
Semih Gorduk ◽  
Hakan Yilmaz ◽  
Omer Andac
Keyword(s):  
Thermal Analysis ◽  
Magnetic Susceptibility ◽  
Coordination Polymer ◽  
Hydrogen Storage ◽  
Coordination Polymers ◽  
Crystalline Form ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas

In this study, two new coordination polymers of Cu(II) and Cd(II) ions with pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole were synthesized. The structures of these coordination polymers were characterized with elemental analysis, infrared spectroscopy, thermal analysis, powder X-ray diffraction, and magnetic susceptibility techniques. According to the results of the thermal analysis, the coordination polymers that contained water molecules decomposed below 100 °C, and the final products for both coordination polymers were the related metal oxides in an oxygen atmosphere. Powder X-ray diffraction analysis revealed that the coordination polymers were in the crystalline form. The hydrogen storage capacities and surface areas of the coordination polymers were also determined. The highest hydrogen storage capacities were measured as 296 ml/g for the Cu(II) coordination polymer and 330 ml/g for the Cd(II) coordination polymer at approximately 75 bar and 75 K.

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