Synthesis of nanosized magnetic NiFe2O4 material by a coprecipitation method

Nanosized NiFe2O4 spinel material has been synthesized by the coprecipitation method by hydrolysis of Ni(II) and Fe (III) cations in boiling water. The DTA/TGA, XRD, SEM, TEM, VSM results showed that NiFe2O4 crystals formed after calcinating at 700 oC for 2 h exhibited the cubic structure, with the size of 30-50 nM. Mr, Ms and Hc values were 1.06 emu/g, 14.94 emu/g and 61.57 Oe, respectively. The crystal size significantly increased with increasing calcination temperature.

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Pressureless Sintering of YIG Ceramics from Coprecipitated Nanopowders

Magnetochemistry ◽

10.3390/magnetochemistry7050056 ◽

2021 ◽

Vol 7 (5) ◽

pp. 56

Author(s):

Yimin Yang ◽

Xiaoying Li ◽

Ziyu Liu ◽

Dianjun Hu ◽

Xin Liu ◽

...

Keyword(s):

High Temperature ◽

Calcination Temperature ◽

Sintering Temperature ◽

Raw Materials ◽

Secondary Phase ◽

Coprecipitation Method ◽

Pressureless Sintering ◽

Densification Behavior ◽

Sintering Process

Nanoparticles prepared by the coprecipitation method were used as raw materials to fabricate Y3Fe5O12 (YIG) ceramics by air pressureless sintering. The synthesized YIG precursor was calcinated at 900–1100 °C for 4 h in air. The influences of the calcination temperature on the phase and morphology of the nanopowders were investigated in detail. The powders calcined at 1000–1100 °C retained the pure YIG phase. YIG ceramics were fabricated by sintering at 1200–1400 °C for 10 h, and its densification behavior was studied. YIG ceramics prepared by air sintering at 1250 °C from powders calcinated at 1000 °C have the highest in-line transmittance in the range of 1000-3000 nm. When the sintering temperature exceeds 1300 °C, the secondary phase appears in the YIG ceramics, which may be due to the loss of oxygen during the high-temperature sintering process, resulting in the conversion of Fe3+ into Fe2+.

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Catalytic Hydrolysis of Hydrogen Cyanide on Cu-Al Catalyst

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1094.15 ◽

2015 ◽

Vol 1094 ◽

pp. 15-19

Author(s):

Lin Xia Yan ◽

Sen Lin Tian ◽

Qiu Lin Zhang

Keyword(s):

Calcination Temperature ◽

Hydrogen Cyanide ◽

Influence Factor ◽

Ph Value ◽

Precipitation Method ◽

Molar Ratio ◽

Cu Content ◽

Co Precipitation ◽

The Impact ◽

Hydrolysis Of

Cu-Al catalysts were synthesized by the co-precipitation method to study hydrolysis of hydrogen cyanide. During the synthesis, the impact of Cu/Al molar ratio, pH value and calcination temperature was investigated and the best synthesis condition was found. The results indicate that the remove of hydrogen cyanide first increases and then decreases with increasing Cu/Al molar ratio, pH value and calcination temperature, which reaches the maxima and remains above 95% at 360 min when Cu/Al molar ratio is 2:1, pH value is approximately 8.0 and calcination temperature is 400°C around. The analysis of X-ray diffraction (XRD) shows that Cu content is the main influence factor at Cu/Al molar ratio below 2:1 whereas crystallinity of catalysts is the key factor at Cu/Al molar ratio above 2:1.

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KARAKTERISASI ABU KAYU MERBAU (Intsia, spp.): PENGARUH TEMPERATUR DAN LAMA KALSINASI

Jurnal Natural ◽

10.30862/jn.v15i1.120 ◽

2019 ◽

Vol 15 (1) ◽

pp. 30-38

Author(s):

Darma Santi ◽

Jacson Victor Morin

Keyword(s):

Calcination Temperature ◽

Wood Ash ◽

Hexagonal Structure ◽

Rhombohedral Structure ◽

Water Molecules ◽

X Ray Diffraction ◽

X Ray ◽

Ft Ir ◽

Cubic Structure

Characterization of merbau wood ash (Intsia, spp.) due to the influence of temperature and time of calcination has been studied. The variations in calcination temperature were 500 ᴼC (as M500) and 600 ᴼC (as M600), while the variations in the duration of calcination were 1, 2, and 3 hours, noted as M1, M2, and M3, respectively. Characterization was carried out using X-ray diffraction (XRD) and spectroscopic analysis using FT-IR. XRD results identified the presence of CaCO3 species (rhombohedral structure) and K2Si4O9 species with a hexagonal structure on M500. The M600 species identified Si (cubic structure), SiO2 (cubic structure), K2Si4O9 (hexagonal structure), and CaCO3 (rhombohedral structure). In general, the calcination temperature increases the crystallinity of several compounds contained in merbau wood ash. The length of time calcination reduces the absorption peak due to the decomposition and adsorption reactions of the presence of water molecules bound to the ash material of merbau wood (Intsia, spp).

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Microstructural Investigation of Fluoroapatite Hydrothermally Converted from Hydroxyapatite Synthesized from Crocodile Eggshell

Journal of Metastable and Nanocrystalline Materials ◽

10.4028/www.scientific.net/jmnm.32.21 ◽

2021 ◽

Vol 32 ◽

pp. 21-32

Author(s):

Reedwan Bin Zafar Auniq ◽

Weerapong Lerdrattranataywee ◽

Upsorn Boonyang

Keyword(s):

Crystal Size ◽

Ph Value ◽

Structure Evolution ◽

Hexagonal Crystal ◽

Microstructural Investigation ◽

Unique Structure ◽

Distinctive Morphology ◽

Cubic Structure ◽

Hexagonal Crystals ◽

Dumbbell Structure

Fluoro/hydroxyapatite (FHAp) were prepared by hydrothermal at 150 °C for 24 hours with different of starting materials. The conversion of hydroxyapatite (HAp) and tricalcium phosphate to FHAp showed the rod-like shape with 200 nm. While, the morphology of FHAp from crocodile eggshell as CaCO3 form with different in phosphorus and fluoride source showed the unique structure evolution from rod-like hexagonal crystals, dumbbell to ball shape. Two distinctive morphology, first when using NaF as fluoride source with (NH4)2HPO4 precursor show the large cubic structure in high magnification it is tufted hexagonal crystal and it bundle like structure. As the pH value decreases in NH4F, it increases crystal size. For H3PO4 as phosphate precursor found that unique structure evolution from rod-like hexagonal crystals to dumbbell structure and then form the sphere assembly with a size of several micrometers.

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Morphology-Controllable Hydrothermal Synthesis of Zirconia with the Assistance of a Rosin-Based Surfactant

Applied Sciences ◽

10.3390/app9194145 ◽

2019 ◽

Vol 9 (19) ◽

pp. 4145 ◽

Cited By ~ 2

Author(s):

Chen Guo ◽

Peng Wang ◽

Shengliang Liao ◽

Hongyan Si ◽

Shangxing Chen ◽

...

Keyword(s):

Hydrothermal Synthesis ◽

Aqueous Solutions ◽

Pore Size ◽

Surface Area ◽

Calcination Temperature ◽

Pore Volume ◽

Crystal Size ◽

Edge Angle ◽

Large Pore Volume ◽

Hollow Cube

With the assistance of a rosin-based surfactant, dehydroabietyltrimethyl ammonium bromine (DTAB), well-dispersed hollow cube-like zirconia particles were firstly synthesized by the hydrothermal treatment of ZrOCl2 aqueous solutions. The introduction of DTAB is crucial for improving the dispersion and regularity of the as-synthesized sample. After calcination, the crystal size of the calcined samples increased, and the edge angle of the cube-like particles became round accordingly. Finally, a hollow spherical morphology was formed for the sample calcined at 923 K. The as-synthesized sample showed big surface area of 146.78 m2/g and large pore volume of 0.23 cm3/g. With the increase of calcination temperature, the surface area and pore volume of the samples decreased significantly, and the pore size increased accordingly.

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Synthesis of M-Hexaferrites Material Based on Natural Iron Sand with Metal Co Doping Using the Coprecipitation Method

Jurnal Penelitian Pendidikan IPA ◽

10.29303/jppipa.v7i1.461 ◽

2020 ◽

Vol 7 (1) ◽

pp. 1

Author(s):

Susilawati Susilawati ◽

Aris Doyan ◽

Lalu Muliyadi

Keyword(s):

Hydrochloric Acid ◽

Calcination Temperature ◽

Mole Fraction ◽

Coprecipitation Method ◽

Distilled Water ◽

Metal Doping ◽

Co Doping ◽

Chloride Hexahydrate ◽

Natural Iron

The synthesis of M-hexaferrite with metal doping Co (BaFe12-3xCoxO19 ) based on natural iron sand at Ketapang beach in Pringgabaya Subdistrict, East Lombok using the coprecipitation method has been successful. The basic ingredients used in this study were natural iron sand and BariumCarbonate (BaCO3) powder, while the doping material used was Cobalt (II) Chloride Hexahydrate (CoCl2.6H2O) powder with a variety of mole fraction (X = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0). The solvent uses 37% hydrochloric acid (HCl), 25% NH4OH solution, and distilled water. The sample formed was then calcined at 200 0C, 400 0C, 600 0C, 800 0C and 1000 0C. The resulting sample shows that there is an effect of Co doping and calcination temperature in the formation of barium M-hexaferrite. The higher the mole fraction of Co doping ions and the calcination temperature, the darker the color of the powder produced.

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Structural evolution and synthesis mechanism of ytterbium disilicate powders prepared by cocurrent chemical coprecipitation method

10.21203/rs.3.rs-929960/v1 ◽

2021 ◽

Author(s):

Nannan Wu ◽

Yalei Wang ◽

Rutie Liu ◽

Huaifei Liu ◽

Xiang Xiong

Keyword(s):

Calcination Temperature ◽

Amorphous Polymer ◽

Structural Evolution ◽

Phase Evolution ◽

Coprecipitation Method ◽

Molar Ratio ◽

Synthesis Mechanism ◽

Chemical Coprecipitation ◽

Atomic Rearrangement ◽

Chemical Coprecipitation Method

Abstract Ytterbium disilicate powders were synthesized by cocurrent chemical coprecipitation method. The influence of Si/Yb molar ratio and calcination temperature on compositions and structures of Yb2Si2O7 products were investigated. The formation mechanism and thermal behavior of precursor as well as the phase evolution of Yb2Si2O7 were also discussed in depth. Results show that pure β-Yb2Si2O7 powders with nanoscale size can be obtained from the precursor with Si/Yb molar ratio of 1.1 after being calcinated at temperatures above 1200 ℃. The Yb2Si2O7 precursor is an amorphous polymer cross-linked with -[Si-O-Yb]- chain segments which are formed though Yb atoms embedding in the -[Si-O-Si]- network. After a continuous dihydroxylation and structural ordering, the amorphous precursor transformed to α-Yb2Si2O7 crystals by atomic rearrangement. Elevated calcination temperature can induce to the coordination structures and environment evolutions of structural units and then converted to stable (Si2O7) groups and (YbO6) polyhedrons, which results in the formation of β-Yb2Si2O7.

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Chemical and Physical Properties of the Al1-xFexPO4 System Prepared by the Coprecipitation Method. II. Surface Acidity, Textural Properties and Catalytic Activity

Adsorption Science & Technology ◽

10.1260/026361702321104246 ◽

2002 ◽

Vol 20 (8) ◽

pp. 741-755 ◽

Cited By ~ 9

Author(s):

F.Sh. Mohamed

Keyword(s):

Catalytic Activity ◽

Calcination Temperature ◽

Pore Volume ◽

Pore Radius ◽

Surface Acidity ◽

Total Pore Volume ◽

Textural Properties ◽

Coprecipitation Method ◽

Temperature Variations ◽

Kinetics Of

A coprecipitation method for the preparation of Al1-xFexPO4 catalysts with x (or Fe/P ratio) = 0.0, 0.2, 0.4, 0.6 and 0.8 was developed. The samples were calcined at temperatures within the range 200–800°C. The surface structure, cumulative acidity, textural properties, and the catalytic activity and selectivity of the prepared samples towards isopropanol and cyclohexane conversion were studied using different techniques. The results showed that the freshly calcined samples consisted of an amorphous phase, a quartz-type and a tridymite-type phase depending on the calcination temperature. The total surface acidity decreased with FePO4 content or calcination temperature. Variations in the Fe/P ratio and the calcination temperature led to changes in both the surface area and total pore volume of the Al1-xFexPO4 samples. Increases in the Fe/P ratio and increasing calcination temperature led to increases in the pore radius. The catalytic activity and selectivity were significantly affected as the structures of the Al1-xFexPO4 catalysts varied. The kinetics of the reaction were also studied.

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Synthesis of bimodally porous titania powders by hydrolysis of titanium tetraisopropoxide

Journal of Materials Research ◽

10.1557/jmr.2000.0334 ◽

2000 ◽

Vol 15 (11) ◽

pp. 2322-2329 ◽

Cited By ~ 28

Author(s):

Ki Chang Song ◽

Sotiris E. Pratsinis

Keyword(s):

Phase Composition ◽

Calcination Temperature ◽

Water Concentration ◽

Nitrogen Adsorption ◽

Molar Ratio ◽

Titanium Tetraisopropoxide ◽

X Ray Diffraction ◽

Porous Titania ◽

Nitrogen Adsorption Isotherms ◽

Hydrolysis Of

Bimodally porous titania powders with controlled phase composition and porosity were made by hydrolysis of titanium tetraisopropoxide (TTIP) and calcination. The extent of calcination was followed by thermogravimetric differential thermal analysis and Fourier transform infrared spectroscopy. The specific surface area (SSA) of the powders ranged from 10 to 500 m2/g as determined by nitrogen adsorption. The SSA increased by decreasing either the water concentration during hydrolysis or the calcination temperature. The pore size distribution was bimodal with fine intraparticle pore diameters at 1–6 nm and larger interparticle pore diameters at 30–120 nm as determined by nitrogen adsorption isotherms. The particle phase composition as determined by x-ray diffraction ranged from amorphous to crystalline anatase and rutile largely proportional to the calcination temperature and to a lesser extent on the initial H2O/TTIP molar ratio.

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