scholarly journals Microwave-Assisted Molten-Salt Facile Synthesis of Chromium Carbide (Cr3C2) Coatings on the Diamond Particles

2019 ◽  
Vol 38 (2019) ◽  
pp. 370-379 ◽  
Author(s):  
Lei Xu ◽  
Chenlong Wei ◽  
Wei Li ◽  
Libo Zhang ◽  
Jinhui Peng
Keyword(s):  
Molten Salt ◽  
Chromium Carbide ◽  
Coating Thickness ◽  
Raw Materials ◽  
Heating Temperature ◽  
Molten Salt Synthesis ◽  
Positive Role ◽  
Temperature Range ◽  
Microwave Assisted ◽  
Diamond Particles

AbstractChromium carbide (Cr3C2) coatings on the diamond were fabricated using the mixtures of molten salt of NaCl and BaCl2, powders of metallic chromium and diamond as raw materials in the temperature range of 750–900 °C by the microwave-assisted molten-salt synthesis. The morphology, microstructure and phase composition of the surface layer were characterized by Scanning Electron Microscopy, Energy-dispersive Spectrometry and X-ray diffraction. The results show that the surface of the diamond particles could be coated with Cr, forming a uniform and continuous Cr3C2-coated layer. The coatings thickness on the diamond can be controlled by adjusting the heating temperature and time. The coating thickness expanded from 0.73 to 2.30 µm when the temperature was increased from 750 °C to 900 °C, and increasing rapidly during the temperature range of 800  °C–850  °C, the coating thickness expanded from 1.30 to 2.80 µm when the holding time was increased from 0.5 h to 4 h. The results illustrate that the microwave-assisted molten salt synthesis plays a positive role in chromium coatings on the diamond, offering a potent method for the surface metallization of diamond.

Effects of Starting Materials on Molten Salt Synthesis of Bi4Ti3O12

2008 ◽  
Vol 55-57 ◽  
pp. 165-168
Author(s):  
Paisan Setasuwon ◽  
S. Kijamnajsak
Keyword(s):  
Molten Salt ◽  
Grain Growth ◽  
Grain Orientation ◽  
Crystal Size ◽  
Raw Materials ◽  
Piezoelectric Materials ◽  
Molten Salt Synthesis ◽  
Chloride Salt ◽  
Templated Grain Growth

Na0.5Bi0.5TiO3 is one of the potential candidates for non-lead piezoelectric materials to replace existing lead-based ones. Properties of BNT could be enhanced by reactive templated grain growth (RTGG) technique through induction of grain orientation with crystals of Bi4Ti3O12. Controlling the size of Bi4Ti3O12 crystals during the synthesis with molten salt is a major factor in optimizing RTGG. It was found that molten salt synthesis of Bi4Ti3O12 crystals with NaCl-KCl yielded larger particles, compared with Na2SO4-3K2SO4. Varying the proportion of chloride salt did not produce noticeable changes in crystal size. Bi4Ti3O12 crystals were significantly affected by raw materials treatment. Non-milling of starting powders could approximately double the crystal size

scholarly journals Low-Temperature Molten Salt Synthesis and the Characterisation of Submicron-Sized Al8B4C7 Powder

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 70
Author(s):  
Cheng Liu ◽  
Xueyin Liu ◽  
Zhaoping Hou ◽  
Quanli Jia ◽  
Benjun Cheng ◽  
...  
Keyword(s):  
Low Temperature ◽  
Molten Salt ◽  
Raw Materials ◽  
Reaction Medium ◽  
Thermal Reduction ◽  
Molten Salt Synthesis ◽  
Synthesis Process ◽  
Direct Reaction ◽  
Liquid Reaction ◽  
Reduction Methods

Submicron-sized (~200 nm) aluminium boron carbide (Al8B4C7) particles were synthesised from Al, B4C and carbon black raw materials in a molten NaCl-based salt at a relatively low temperature. The effects of the salt type/assembly and the firing temperature on the synthesis process were examined, and the relevant reaction mechanisms discussed. The molten salt played an important role in the Al8B4C7 formation process. By using a combined salt of 95%NaCl + 5%NaF, an effective liquid reaction medium was formed, greatly facilitating the Al8B4C7 formation. As a result, essentially phase-pure Al8B4C7 was obtained after 6 h of firing at 1250 °C. This temperature was 350–550 °C lower than that required by the conventional direct reaction and thermal reduction methods.

Molten Salt Synthesis of Ni0.5Zn0.5Fe2O4 Ferrites

2012 ◽  
Vol 512-515 ◽  
pp. 1420-1423
Author(s):  
Hong Tao Jiang ◽  
Xiu Feng Wang ◽  
Li Li Wang ◽  
Cheng Long Yu
Keyword(s):  
Molten Salt ◽  
Raw Materials ◽  
Initial Permeability ◽  
Holding Time ◽  
Molten Salt Synthesis ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Text Structures ◽  
Average Grain Size ◽  
Zno Powders

In this paper, Ni0.5Zn0.5Fe2O4ferrite ceramics were produced with Ni0.5Zn0.5Fe2O4powders prepared by reaction in a molten salt using Fe2O3, NiO and ZnO powders as raw materials. Ni-Zn powders were characterized by X-ray diffraction (XRD). Density and shrinkage in diameter of Ni0.5Zn0.5Fe2O4ceramics were measured. MicroSubscript text structures were observed using field emission scanning electron microscopy (FESEM), and magnetic properties were examined by HP4291B impedance analyzer. XRD pattern indicated that the powders synthesized at 900°C for 1h were pure spinel Ni0.5Zn0.5Fe2O4phase. Via the measurement of density and shrink in diameter, optimal temperature was 1200°C and holding time was 2h, which was in accord with the results concluded from micrographs. FESEM images illustrated that the average grain size increased with increasing holding time, which followed the Ostwald liquid growth mechanism. At lower frequencies, the initial permeability (μi) increased from 86.65 to 183.48 with increasing holding time, while the threshold frequency decreased from 13.3MHz to 8.52MHz, which implied the initial permeability (μi) variation complied with the Snoek law to some extent.

Molten salt synthesis of YAG:Ce3+ phosphors from oxide raw materials

2014 ◽  
Vol 40 (3) ◽  
pp. 5067-5071 ◽  
Author(s):  
Lin Gan ◽  
Zhi-Yong Mao ◽  
Fang-Fang Xu ◽  
Ying-Chun Zhu ◽  
Xue-Jian Liu
Keyword(s):  
Molten Salt ◽  
Raw Materials ◽  
Molten Salt Synthesis

Formation Mechanism of SrBi2Nb2O9 Prepared by Melting Salt Method

2010 ◽  
Vol 177 ◽  
pp. 12-15
Author(s):  
Bao Rang Li ◽  
Xing Tao Liu ◽  
Yang Sheng Zheng ◽  
Hui Bin Chang
Keyword(s):  
Molten Salt ◽  
Formation Mechanism ◽  
Reaction Mechanisms ◽  
Synthesis Method ◽  
Molten Salt Synthesis ◽  
Synthesis Reaction ◽  
Simple Route ◽  
Temperature Range ◽  
Synthesis Route ◽  
Molten Medium

In this paper SrBi2Nb2O9 was prepared by molten salt synthesis method and KCl chosen as molten medium. In order to disclose possible formation mechanism of SrBi2Nb2O9, a simple route was established for comparison by dividing the starting precursors into four groups. With the help of XRD, possible synthesis route was analyzed. The results showed that pure SrBi2Nb2O9 powders could be obtained at temperature higher than 700oC by molten salt synthesis. Intense synthesis reaction happened in the temperature range from 500 to 700oC. The reaction mechanisms of SrBi2Nb2O9 included four steps, namely the formation of 1) SrBi2O4 at close to 600oC,2) BiNbO4 from the reaction of at 600-700 oC, 3) SrBi2Nb2O9 from the reaction of SrBi2O4 and Nb2O5 and 4)SrBi2Nb2O9 from the reaction of BiNbO4 and SrCO3. The molten salt could improve distribution and reactivity of the precursors and significant formation of SrBi2Nb2O9.

scholarly journals Microstructure and Morphology Control of Potassium Magnesium Titanates and Sodium Iron Titanates by Molten Salt Synthesis

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1577 ◽  
Author(s):  
Haoran Zhang ◽  
Mengshuo Li ◽  
Ze Zhou ◽  
Liming Shen ◽  
Ningzhong Bao
Keyword(s):  
Molten Salt ◽  
High Performance ◽  
Large Scale ◽  
Raw Materials ◽  
Synthesis Method ◽  
Molten Salt Synthesis ◽  
Molar Ratio ◽  
Molten Salt Method ◽  
Experimental Conditions ◽  
Potassium Magnesium

Titanates materials have attracted considerable interest due to their unusual functional and structural properties for many applications such as high-performance composites, devices, etc. Thus, the development of a large-scale synthesis method for preparing high-quality titanates at a low cost is desired. In this study, a series of quaternary titanates including K0.8Mg0.4Ti1.6O4, Na0.9Mg0.45Ti1.55O4, Na0.75Fe0.75Ti0.25O2, NaFeTiO4, and K2.3Fe2.3Ti5.7O16 are synthesized by a simple molten salt method using inexpensive salts of KCl and NaCl. The starting materials, intermediate products, final products, and their transformations were studied by using TG-DSC, XRD, SEM, and EDS. The results show that the grain size, morphology, and chemical composition of the synthesized quaternary titanates can be controlled simply by varying the experimental conditions. The molar ratio of mixed molten salts is critical to the morphology of products. When KCl:NaCl = 3:1, the morphology of K0.8Mg0.4Ti1.6O4 changes from platelet to board and then bar-like by increasing the molar ratio of molten salt (KCl–NaCl) to raw materials from 0.7 to 2.5. NaFeTiO4 needles and Na0.75Fe0.75Ti0.25O2 platelets are obtained when the molar ratio of molten salt (NaCl) to raw materials is 4. Pure phase of Na0.9Mg0.45Ti1.55O4 and K2.3Fe2.3Ti5.7O16 are also observed. The formation and growth mechanisms of both potassium magnesium titanates and sodium iron titanates are discussed based on the characterization results.

SYNTHESIS OF ANISOTROPIC LEAD TITANATE POWDERS FOR TEMPLATED GRAIN GROWTH OF TEXTURED PIEZOELECTRIC CERAMICS

2010 ◽  
Vol 17 (02) ◽  
pp. 159-164 ◽  
Author(s):  
S. MA ◽  
J. Y. H. FUH ◽  
Y. F. ZHANG ◽  
L. LU
Keyword(s):  
Molten Salt ◽  
Heating Temperature ◽  
Synthesis Method ◽  
Processing Parameters ◽  
Molten Salt Synthesis ◽  
X Ray Diffraction ◽  
Thermal Synthesis ◽  
Flux Synthesis ◽  
One Step ◽  
Molten Salt System

Needle-shaped PbTiO3 (PT) template particles were successfully synthesized using two different types of approaches, molten salt synthesis (MSS) and thermal synthesis method. In eutectic NaCl–KCl molten salt system, homogeneous and nonagglomerated needle-shaped PT particles were produced from PbO and needle-like TiO2 compound heated at 800–850°C for 2 h. The effect of heating temperature on the morphology of formed powders was studied in order to identify the optimum processing parameters. The template formation mechanism is discussed. Using thermal synthesis method, comparable needle-shaped PT crystalline particles were also obtained in one step. Plate-shaped PT powders were derived via flux synthesis. The effect of additives such as MnCl2 and LiF on the morphology of derived PT was studied. Adding a certain amount of MnCl2 led to the formation of well-defined plate-shaped PT particles. The structure and morphology of synthesized powders were characterized by means of X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM).

Synthesis and Reaction Mechanism of Ti3SiC2 by Molten Salt Method from Ti-Si-Fe Alloy

2018 ◽  
Vol 768 ◽  
pp. 159-166 ◽  
Author(s):  
Jin Hua Zhang ◽  
Si Xiong ◽  
Chang Ming Ke ◽  
Hong Dan Wu ◽  
Xin Rong Lei
Keyword(s):  
Electron Microscope ◽  
Molten Salt ◽  
Raw Materials ◽  
Synthesis Method ◽  
Molten Salt Synthesis ◽  
Synthesis Process ◽  
Molten Salt Method ◽  
Synthetic Temperature ◽  
Chloride Salts ◽  
Titanium Silicon

Titanium silicon carbide (Ti3SiC2) were obtained by molten salt synthesis method using the Ti-Si-Fe alloy extracted from high titania blast furnace slag and natural graphite as the raw materials. The phase composition, microscopic structure of the products were characterized by powder X-ray diffraction, scanning electron microscope and transmission electron microscope. The influence of firing temperature and chloride salts species on the phase and morphology of the products were investigated. The results indicated that the synthetic temperature of Ti3SiC2 by molten salt synthesis method was about 100 °C, which was lower than that without molten salts. The “dissolution-precipitation” mechanism governed the overall molten salt synthesis process. The lamellar Ti3(Si,Al)C2 crystal growth obeyed by a two-dimensional ledge growth mechanism.

Flaky and Porous Rod-Like MgO Powders Prepared by Molten Salt Synthesis

2011 ◽  
Vol 335-336 ◽  
pp. 674-677
Author(s):  
Jian Qi Sun ◽  
Hao Chen ◽  
Fei Cao ◽  
Qing Hua Hu
Keyword(s):  
Molten Salt ◽  
Surface Area ◽  
Raw Materials ◽  
Growth Direction ◽  
Molten Salt Synthesis ◽  
Width Ratio ◽  
Single Slice

Flaky and porous rod-like MgO powders were prepared by molten salt synthesis with MgCl2, CaCO3, NaNO3and KNO3as raw materials. TG-DSC, XRD and SEM were used to investigate the reacion process and characterize the resulting products. The results indicated that Ca2+was displaced by Mg2+and dolomites were formed and finally converted into magnesium carbonates during the molten salt synthesis. Fibrous Mg(OH)2formed in PEG solution and flaky Mg(OH)2formed in EDTA-PEG solution illustrated that EDTA and PEG molecules could define the growth direction of Mg(OH)2. The porous rod-like MgO powders with 20-80 nm in diameter and 40-100 in length-to-width ratio were obtained by the decomposition of fibrous Mg(OH)2at 600 °C, while the flaky MgO powders were prepared by the decomposition of flaky Mg(OH)2at 600 °C. Flaky MgO powders were platelike, with 30-50 nm in thickness, 200-500 nm in diameter, and up to 1.0 µm2in a single slice surface area.

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