Solidification Characterization of K418 Alloy Powders Fabricated by Argon Gas Atomization

2016 ◽  
Vol 849 ◽  
pp. 788-793 ◽  
Author(s):  
Liang Liang Lu ◽  
Shao Ming Zhang ◽  
Jun Xu ◽  
Yan Wei Sheng ◽  
Shan Shan Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Cooling Rate ◽  
Particle Surface ◽  
Spherical Shape ◽  
Solidification Process ◽  
Average Diameter ◽  
Powder Particle Size ◽  
Gas Atomization ◽  
Powder Morphology

The solidification characterization of K418 alloy powders prepared by argon atomization was studied, and thermal parameters of the alloy powder during solidification process were calculated. The results show that powder morphology is spherical shape, the average diameter of the powder is 55μm, the amount of less 100μm powder is about 90 percent, the solidification microstructure of powders particle surface are dentrite and cellular structure. Decreasing the particle size, the microstructures of particle interior change from dentrite in major to cellular structures, and the structure is more uniformed. The length of secondary dentritic arm and the cooling rate as a function of K418 alloy powders size is established, the cooling rate increases with a decrease of the powder particle size, the cooling rate is in the range of 104K.S-1-106K.S-1.

Characterization of Cooling Rate and Microstructure of Rapidly Solidified Spherical Mono-Sized Sn-1.0Ag-0.5Cu Particles

2019 ◽  
Vol 960 ◽  
pp. 274-283
Author(s):  
Ying Yan Hu ◽  
Jun Feng Wang ◽  
Can Li ◽  
Jian Qiang Li
Keyword(s):  
Particle Size ◽  
Cooling Rate ◽  
Rapid Solidification ◽  
Great Influence ◽  
Particle Diameter ◽  
Spherical Shape ◽  
Phase Size ◽  
Rapidly Solidified ◽  
The Relationship

Spherical mono-sized Sn-1.0Ag-0.5Cu (wt.%) particles with diameter ranging from 124.0 to 337.4μm were prepared by the pulsated orifice ejection method (termed “POEM”).These spherical Sn-1.0Ag-0.5Cu particles exhibit a good spherical shape and a narrow size distribution, suggesting that liquid Sn-1.0Ag-0.5Cu can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the relationship between cooling rate and microstructures of spherical Sn-1.0Ag-0.5Cu particles was studied with a specific focus on different particle diameter during the rapid solidification. The cooling rate of spherical Sn-1.0Ag-0.5Cu particles with different diameter was evaluated by the Newton’s cooling model. It is revealed that the cooling rate decreases gradually with the increase of particle size during the rapidly solidified process. When the particle diameter is equal to 75 μm, the cooling rate of the Sn-1.0Ag-0.5Cu particle achieves 4.30×103 K/s which indicates that smaller particles can rapidly solidified due to their higher cooling rate. Meanwhile, the cooling rate decreases rapidly when the particle diameter increases between 75 and 100 μm. Furthermore, the different particle diameter with different cooling rate has a great influence on the solidification microstructure of Sn-1.0Ag-0.5Cu particles. The cooling rate and grain boundary size decreases with the increase of particle diameter during the rapid solidification. In addition, the phase size of βSn increases with the decrease of particle size. Smaller particles have relatively high cooling rate and it gives less solidification time as compared to larger particles. It is an effective route for fabrication of high-quality spherical Sn-1.0Ag-0.5Cu particles. Keywords: Spherical Sn-1.0Ag-0.5Cu particles; Rapid solidification; Structural; Cooling rate

Isolasi Dan Karakterisasi Bentonit Alam Menjadi Nanopartikel Monmorillonit

2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Surface Morphology ◽  
Average Diameter ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Scanning Electron ◽  
Sedimentation Processes

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>

Preparation of Nanosized Barium Titanate Powder by a Direct Reactive Precipitation Method

2013 ◽  
Vol 690-693 ◽  
pp. 454-457
Author(s):  
Hong Bo Li ◽  
Shu Yan Wu ◽  
Jing Wang ◽  
Chun Jie Li
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Surface Active Agent ◽  
Average Particle Size ◽  
Active Agent ◽  
Precipitation Method ◽  
Precipitation Process ◽  
Average Particle ◽  
Powder Particle Size ◽  
Powder Morphology

Columnar crystaldendriteequiaxial dendritescolumnar crystalNanosized powder was synthesized by direct-reactive precipitation process using a stoichiometrical mixture of TiCl4, BaCl2 as the reactants while NaOH as precipitant. Under the ratio of Ba to Ti is 1.02, PH=13, three reaction temperature of 70°C, 80°C and 90°C were conducted respectively. Morphology and phase structure of powder were investigated, and the influence of reaction temperature on powder morphology was discussed. The result indicates that synthesized powder is single cubic BaTiO3 and contains no impurities. BaTiO3 powders generally show spherical, and average particle size decreases with increasing reaction temperature. When reaction temperature is 80°C, BaTiO3 powder has best uniformity and dispersivity with the diameter of 80-100nm. The influence of reaction temperature on powder particle size can be attributed to the corporate contribution of nucleation and growth rate. Polyglycol as surface active agent has a significant effect in restraining agglomeration.

scholarly journals Production and characterization of lipid microparticles produced by spray cooling encapsulating a low molar mass hydrophilic compound

2010 ◽  
Vol 30 (1) ◽  
pp. 276-281 ◽  
Author(s):  
Alda Jusceline Leonel ◽  
Hulda Noemi Mamani Chambi ◽  
Daniel Barrera-Arellano ◽  
Heloise Oliveira Pastore ◽  
Carlos Raimundo Ferreira Grosso
Keyword(s):  
Glucose Solution ◽  
Spherical Shape ◽  
Average Diameter ◽  
Solution Concentration ◽  
Spray Cooling ◽  
The Core ◽  
Lipid Mixtures ◽  
Continuous Surface ◽  
Lipid Microparticles

The objective of this research was to produce and characterize lipid particles (MpLs) that may be used as carriers of high amounts of hydrophilic core and evaluate the influence of the core amount on the performance of lipid microparticles. The MpLs were produced by spray cooling from solid and liquid lipid mixtures (stearic and oleic fatty acids and partly hydrogenated vegetable fat) containing glucose solution as core and soy lecithin as surfactant. The performance of MpLs was evaluated by means of the effective amount of encapsulated core, the core amount present on the surface of MpLs (superficial glucose) and the core release profile in aqueous solution. Morphological observations showed that MpLs presented spherical shape and a rugged and continuous surface, and an average diameter between 25 and 32 µm. The effective amount of encapsulated core was greater than 78% for all formulations evaluated. Larger amounts of superficial glucose were found in formulations in which more concentrated glucose solutions were used, regardless of the glucose lipid-solution ratio. The release results showed that core retention was significantly influenced by the glucose solution concentration, whereas release modulation was influenced by the glucose lipid-solution ratio.

Characterization of H13 steel powder oxidation at different temperatures

2021 ◽  
Vol 112 (1) ◽  
pp. 42-47
Author(s):  
Hengsan Liu ◽  
Miaohui Wang ◽  
Yifei Xu ◽  
Xueyuan Ge ◽  
Jing Li ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Oxidation Behavior ◽  
Steel Powder ◽  
Oxide Phase ◽  
Oxidation Products ◽  
Powder Particle Size ◽  
H13 Steel ◽  
Different Temperatures

Abstract The oxidation behavior of two kinds of H13 steel powders were studied at different temperatures in air. Both oxidation kinetics and oxidation products were investigated, and the effect of powder particle size distribution on the powder oxidation was also evaluated. In addition, elemental and microstructural analyses were also conducted to characterize the oxide phase formation. Results showed that chromia and spinel were the main phases for both samples after oxidation for 24 h, irrespective of significant descaling.

scholarly journals Preparation and Physical Chemistry Characterization of New Nanostructured Oxides Catalysts by Spray Pyrolysis Method for the Biodiesel Production

2018 ◽  
Vol 912 ◽  
pp. 7-11
Author(s):  
Silvania Lanfredi ◽  
Elisabeth Djurado ◽  
Marcos A.L. Nobre
Keyword(s):  
Spray Pyrolysis ◽  
Particle Surface ◽  
Double Perovskite ◽  
Average Crystallite Size ◽  
Biodiesel Production ◽  
Spray Pyrolysis Method ◽  
Powder Morphology ◽  
Synthesis Conditions ◽  
Pyrolysis Method

In this work were synthesized new catalysts of stoichiometries Sr0.8K0.2TiCu0.10O3, Sr0.7K0.3TiCu0.15O3 and Sr0.5K0.5TiCu0.25O3 by spray pyrolysis method. The synthesis conditions were optimized to obtain single phase powder of titanates of double perovskite structure, with an ultrasound vibration frequency of 1.3 MHz at 700 °C under air flow. The average crystallite size of the powders, determined by the Scherrer equation and using the Jade Plus 8 software, was at around 9 nm. The powder morphology was analyzed by scanning electron microscopy (SEM). The Sr0.5K0.5TiCu0.25O3 system showed particles with smooth surfaces, spherical and with smaller agglomerates than Sr0.8K0.2TiCu0.10O3, Sr0.7K0.3TiCu0.15O3 systems. This phenomenon suggests that the stoichiometry changes the aspect of the particle surface, which may influence in the catalytic activity. Thus, particles without roughening and smaller size can act as promising catalysts.

scholarly journals Design, Preparation, and Characterization of Dioscin Nanosuspensions and Evaluation of Their Protective Effect against Carbon Tetrachloride-Induced Acute Liver Injury in Mice

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Hong-Ye JU ◽  
Kun-Xia Hu ◽  
Guo-Wang Zhao ◽  
Zhi-Shu Tang ◽  
Xiao Song
Keyword(s):  
Particle Size ◽  
Protective Effect ◽  
Soybean Lecithin ◽  
Chemical Properties ◽  
Spherical Shape ◽  
Positive Control ◽  
The Body

The purpose of this study was to prepare a dioscin nanosuspension (Dio-NS) that has a better distance and high solubility for oral administration and to evaluate its hepatoprotective effects. Optimal primary manufacture parameters, including shear time, shear speed, emulation temperature, pressure, and cycles of homogenization, were determined by single-factor experiments. The concentrations of dioscin, SDS, and soybean lecithin were optimized using the central composite design-response surface method, and their effects on the mean particle size (MPS) and particle size distribution of Dio-NS were investigated. Characterization of the Dio-NS formulations included examinations of the surface morphology and physical status of dioscin in Dio-NS, the stability of Dio-NS at different temperatures, in vitro solubility, and liver protective effect in vivo. Under optimal conditions, Dio-NS had an MPS of 106.72 nm, polydispersity index of 0.221, and zeta potential of −34.27 mV. Furthermore, the proportion of dioscin in Dio-NS was approximately 21.26%. The observation of particles with a spherical shape and the disappearance of crystalline peaks indicated that the physical and chemical properties of Dio-NS were altered. Furthermore, we observed that the dissolution of Dio-NS was superior to that of a physical mixture and Dio-GZF. Moreover, Dio-NS was demonstrated to have a protective effect against CCl4-induced acute liver damage in mice that was equivalent to that of silymarin (a positive control drug) at the same dose. The good hepatoprotective effect of our Dio-NS preparation can provide a theoretical basis for investigating its absorption mechanisms in the body.

SYNTHESIS OF ANATASE TiO2 PARTICLES AND THEIR SIZE-RELATED STRUCTURAL, OPTICAL AND RAMAN SPECTROSCOPY STUDIES

2008 ◽  
Vol 17 (02) ◽  
pp. 167-174 ◽  
Author(s):  
NGUYEN CAO KHANG ◽  
NGUYEN VAN MINH
Keyword(s):  
Particle Size ◽  
Raman Spectroscopy ◽  
Structural Phase ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Raman Spectroscopic ◽  
Promising Application ◽  
Spectroscopy Studies

We have prepared TiO 2 anatase in powder form, studied their structure, Raman spectroscopic and optical properties in relation with the particle size. The average diameter of the particles was found by XRD pattern and SEM to be in the range of 1 μm-10 nm, depending on the synthesis condition. The effects of annealing temperature on the morphology, structural phase and particle size distribution of the particles were studied by scanning electron microscopy, X-ray diffraction, Raman spectroscopy and optical absorption techniques. The distinct changes of the measured results with respect to variations in particle size and synthesis parameter signify the promising application of the optical and Raman spectroscopy for comprehensive physical characterization of nanoparticles.

scholarly journals Green Synthesis Nanopartikel Perak (Agnps) Terkonjugasi Etil Parametoksi Sinamat (Epms) sebagai Bahan Tabir Surya

2018 ◽  
Vol 4 (2) ◽  
pp. 98-105
Author(s):  
Agustina Agustina ◽  
Munawarah Munawarah ◽  
Stefanus Agustinus Lumi ◽  
Syamsu Nur
Keyword(s):  
Particle Size ◽  
Green Synthesis ◽  
Average Diameter ◽  
Raw Material ◽  
Uv Exposure ◽  
Wave Number ◽  
Ftir Analysis ◽  
Natural Materials ◽  
Kaempferia Galanga

Green Synthesis is a method to make silver nanoparticles (AgNPs) by utilizing natural materials as bioreductors. One of the natural materials that can reduce metal ions is Kaempferia galanga rhizome because it has a chemical component that can penetrate the metal. The compounds are ethyl paramethoxycinnamate (EPMC) which is used as sunscreen. This study aims to produce AgNPs conjugated with EPMC that can be used as raw material sunscreen. This study was conducted by extracting EPMS from the Kaempferia galanga rhizome and synthesizing the AgNPs conjugated with EPMC. The synthesis results were characterized by UV-Vis Spectrophotometry, FTIR, SEM, PSA and sunscreen activity. Extracted result was obtained crystalline is ethyl paramethoxycinnamate compound with yield 2,3%. The characterization of EPMC with UV-Vis spectrophotometer was obtained maximum wavelength of 308 nm and FTIR analysis result at wave number 1701,27 cm-1 indicated the presence of carbonyl group (C = O) and 1165,97 cm-1 presence of C-O and showed specific characteristic from EPMS. Characterization of AgNPs using Uv-Vis spectrophotometer was obtained maximum wavelength of 469 nm. Characterization of AgNPs using SEM are spherical and monodispers forms.  Then, particle size using PSA obtained an average diameter of 182 nm. AgNPs conjugated with EPMS has a sunscreen activity with sunblock category and successfully provide protection against UV exposure at low concentration (200 ppm) categorized as ultra protection with SPF value 36,4.

scholarly journals Effect of Cooling Rate and Slag Modification on the Copper Matte in Smelting Slag

2020 ◽  
Vol 37 (5) ◽  
pp. 1593-1601
Author(s):  
Xiang Gao ◽  
Zhuo Chen ◽  
Junjie Shi ◽  
Pekka Taskinen ◽  
Ari Jokilaakso
Keyword(s):  
Particle Size ◽  
Cooling Rate ◽  
Copper Matte ◽  
Controlled Cooling ◽  
Slow Cooling ◽  
Rich Phase ◽  
Metal Ratio ◽  
Smelting Slag ◽  
Slag Modification

Abstract The amount of copper flash smelting slag has increased during the recent years along with an increasing slag-to-metal ratio. During slag tapping, some copper sulfide is mechanically entrained. As a result, it is necessary to recover copper matte from the slag by suitable methods. At present, the most common way is slow, controlled cooling in a transfer ladle. However, research on the detailed effects of slow cooling and the function of slag modification is rare. This paper described experiments that were performed at different cooling rates (0.5, 1.5, 3, and 7 °C/min), with and without additive. A detailed characterization of the copper-rich phase and its particle size was subsequently made using SEM-EDS micrographs and image analysis software. With a decrease in cooling rate, the particle size of the copper-rich matte phase became larger. The addition of gypsum and carbon as a slag modifier affected the size of the copper-rich phase slightly, and its chemical composition was modified compared with the experiments without additive.

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