Electrically-activated Reaction Synthesis (EARS) of Ni-CNT/Al Hierarchical Composite Powders

2020 ◽  
pp. 1-14
Author(s):  
Prathmesh Modi ◽  
Mehul Chauhan ◽  
Vanessa Bundy ◽  
Khaled Morsi
Keyword(s):  
Particle Size ◽  
Mechanical Milling ◽  
Milling Time ◽  
Nickel Particle ◽  
Major Influence ◽  
Reaction Synthesis ◽  
Particle Sizes ◽  
Composite Powders ◽  
Reaction Characteristics ◽  
First Time

Abstract The present study investigates the fabrication of Ni3Al-CNT nanocomposite using electrically-activated reaction synthesis (EARS) and its effects on the mechanical properties of the nanocomposite. The effect of initial nickel (Ni) particle size and mechanical milling time of Ni-CNT/Al hierarchical composite powder on reaction characteristics, product microstructure and properties was investigated for the first time. An increase in mechanical milling time was found to result in a decline in ignition temperature and time to ignition for the two investigated initial nickel particle sizes (4-8µm and 45-90µm). The smaller initial nickel particle size and longer milling times had a major influence on the homogeneity, decreasing porosity and increasing hardness of the reacted compacts.

Prediction of the influence of processing parameters on synthesis of Al2024-B4C composite powders in a planetary mill using an artificial neural network

2014 ◽  
Vol 21 (3) ◽  
pp. 411-420 ◽  
Author(s):  
Temel Varol ◽  
Aykut Canakci ◽  
Sukru Ozsahin
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Particle Size ◽  
Milling Time ◽  
Planetary Mill ◽  
Reinforcement Ratio ◽  
Percentage Error ◽  
Composite Powders ◽  
Neural Network Approach ◽  
Artificial Neural

AbstractIn this study, an artificial neural network approach was employed to predict the effect of B4C size, B4C content, and milling time on the particle size and particle hardness of Al2024-B4C composite powders. Al2024-B4C powder mixtures with various reinforcement weight percentages (5%, 10%, and 20% B4C), reinforcement size (49 and 5 μm), and milling times (0–10 h) were prepared by mechanical alloying process. The properties of the composite powders were analyzed using a laser particle size analyzer for the particle size and a microhardness tester for the powder microhardness. The three input parameters in the proposed artificial neural network (ANN) were the reinforcement size, reinforcement ratio, and milling time. Particle size and particle hardness of the composite powders were the outputs obtained from the proposed ANN. The mean absolute percentage error for the predicted values did not exceed 4.289% for the best prediction model. This model can be used for predicting properties of Al2024-B4C composite powders produced with different reinforcement size, reinforcement ratio, and milling times.

Component of Cu/n-SiO2 Composite Particles by Mechanical Milling

2011 ◽  
Vol 299-300 ◽  
pp. 1320-1323
Author(s):  
Jian Hua Du ◽  
Xiao Hui Zheng ◽  
Xiao Ying Zhu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Milling ◽  
Milling Time ◽  
Composite Particles ◽  
Composite Powders ◽  
X Ray ◽  
Scanning Electron

Copper based composite powders with nano-SiO2 were prepared by mechanical milling technology. The effects of milling time on morphology and component of the composite particles were characterized by scanning electron microscopy (SEM) and energy disperse X-ray spectroscopy (EDS), respectively. Results showed that dendrite composite particles change to the flaky, and then to spherical ones with the milling time increasing. The n-SiO2 particles disperse more homogeneously in the composite particles with the milling time increasing.

scholarly journals Influence of the Oxide and Ethanol Surface Layer on Phase Transformation of Al-Based Nanocomposite Powders under High-Energy Milling

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1305 ◽  
Author(s):  
Dora Janovszky
Keyword(s):  
Particle Size ◽  
Milling Time ◽  
High Energy ◽  
Amorphous Structure ◽  
Control Agent ◽  
Dry Milling ◽  
Process Control Agent ◽  
Composite Powders ◽  
High Energy Milling ◽  
Nanocomposite Powders

Pure Al particles reinforced with amorphous-nanocrystalline Cu36Zr48Ag8Al8 particles composite powders were prepared by high-energy milling without and with ethanol. The mechanical milling procedures were compared so that in the case of dry milling the particle size increased owing to cold welding, but the crystallite size decreased below 113 nm. The amorphous phase disappeared and was not developed until 30 h of milling time. Using ethanol as a process control agent, the particle size did not increase, while the amorphous fraction increased to 15 wt.%. Ethanol decomposed to carbon dioxide, water, and ethane. Its addition was necessary to increase the amount of the amorphous structure.

Effect of Powder Particle Size and Substrate Hardening on the Formation of Nanostructured TiC Coating on AISI-D2 Steel by Mechanical Milling

2013 ◽  
Vol 829 ◽  
pp. 471-475
Author(s):  
Farhad Saba ◽  
Shahram Raygan ◽  
Hossein Abdizadeh
Keyword(s):  
Particle Size ◽  
Powder Particle ◽  
Mechanical Milling ◽  
Milling Time ◽  
Structural Characteristics ◽  
High Energy ◽  
Powder Particle Size ◽  
Aisi D2 Steel ◽  
Aisi D2 ◽  
D2 Steel

In this study TiC coating was formed on AISI-D2 steel by mechanical milling. In this regard, steel sample, balls and the powder were placed within a milling vial. Ball milling were carried out with annealed and quench-tempered samples using TiC powder having particle sizes of 44 and 200 μm for 5, 10, 15, 20, 50 and 100 h. During milling treatment, sample surface was exposed to high energy collisions and powder particles trapped between balls and sample adhered to the surface through cold welding. It was shown that the thickness and the structure of the coating depended on powder particle size; hardness and milling time. The thickness of the coating increased at first and decreased thereafter with milling time. The results showed that the substrate hardening decreased the thickness of the coating. Scanning Electron Microscopy (SEM) was employed to investigate the structural characteristics of the coatings. X-ray Diffraction (XRD) analysis was also conducted to determine the kind of phases in the coating. SEM investigations showed that the greatest thickness of the coating was reached after 20 h of milling. Furthermore, no new phases were detected in the XRD results after 100 h. It was shown that the thickness and hardness of coatings with coarse particle size were lower than that of the other. It was revealed that lattice parameter of TiC coating increased with milling time.

Effect of Ti Particle Size on Reaction Synthesis of Ti Aluminide

2012 ◽  
Vol 710 ◽  
pp. 314-319 ◽  
Author(s):  
Rohit Kumar Gupta ◽  
Bhanu Pant ◽  
Vijaya Agarwala ◽  
Parameshwar Prasad Sinha
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Titanium Aluminide ◽  
Reaction Synthesis ◽  
Particle Sizes ◽  
Minor Phase ◽  
Chemical Homogeneity ◽  
Major Phase ◽  
Ti Powder

Titanium aluminide intermetallic was made through reaction synthesis (RS) process using elemental powders. Pressure assisted synthesis was carried out at high temperature under vacuum. Ti powder with two different particle sizes (200μm and 30μm average) were used in RS. Synthesized blocks were homogenized and characterized for chemical homogeneity, density, phase formation and microstructure evolution. Products near to theoretical density have been obtained with uniform chemistry after homogenization. Al3Ti as a major phase along with TiAl as minor phase was confirmed after RS and TiAl along with Ti3Al was observed after homogenization. Homogenization cycle was found to be different for the alloys made through different Ti particle sizes. Significant role of Ti particle size has been observed in this pressure assisted RS process.

Study on the Preparation of Cu/n-SiO2 Composite Particles by Mechanical Milling

2011 ◽  
Vol 295-297 ◽  
pp. 840-843
Author(s):  
Jian Hua Du ◽  
Yuan Yuan Li ◽  
Xiao Hui Zheng
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Mechanical Milling ◽  
Milling Time ◽  
Composite Particles ◽  
Laser Particle Size Analyzer ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Electronic Microscope

Copper coated nano-SiO2 composite particles were prepared by mechanical milling technology. The effects of milling time on morphology, granularity, component and microstructure of the composite particles were characterized by scanning electronic microscope, laser particle size analyzer, energy depressives spectrometer and transmission electron microscope, respectively. Results showed that dendrite composite particles change to the flaky, and then to spherical ones with the milling time increasing. The particle size decreases firstly and then increases with the milling time increasing. The n-SiO2 particles disperse more homogeneously in the composite particles with the milling time increasing.

Crystallite Growth Kinetics of BaFe12O19/SrTiO3 Based Composites Derived from Mechanical Alloying

2013 ◽  
Vol 789 ◽  
pp. 42-48
Author(s):  
Rahmat Doni Widodo ◽  
A. Manaf ◽  
P. Sardjono
Keyword(s):  
Particle Size ◽  
Growth Kinetics ◽  
Milling Time ◽  
Piezoelectric Materials ◽  
Barium Hexaferrite ◽  
Functional Materials ◽  
Grain Structure ◽  
Crystallite Growth ◽  
Relaxation Equation ◽  
Composite Powders

Barium hexaferrite and strontium titanate are respectively well established permanent magnet and piezoelectric materials which are technologically and scientifically attractive due to their potential for various applications in the field of magnetic electronics functional materials. However, the material properties for both require a careful control of grain structure as well as microstructure design to meet specific applications. In this work, we report some results of materials characterization especially particles and crystallites in a BaFe12O19/SrTiO3 composite which were promoted during mechanical milling. The composite was synthesized using a planetary ball mill with a ball to powder ratio 10:1. Changing in the particle and crystallite-sizes at various milling time up to 60 hours are studied with the aid of particle-size analyzer and X-ray diffraction. It was found that the particle size of composite powders initially increased due to laminated layers formation of a composite and then decreased to an asymptotic value of ~8 μm as the milling time extended even to a relatively longer time. However, based on results of line broadening analysis the mean crystallite size of the particles was found in the nanometer scale. We thus believed that mechanical blending and milling of mixture components for the composite materials has promoted heterogeneous nucleation and only after successive sintering at 1100 °C the millled powder transformed into particles of nanograin. The crystallite growth kinetics at isothermal temperatures follow the relaxation equation with the activation energy value for BHF (QBHF) and STO (QSTO) are respectively 73.63 kJ/mol and 122.69 kJ/mol.

Effects of Vibratory Disc Milling Time on the Physiochemical and Morphological Properties of Coal Fly Ash Nanoparticles

2019 ◽  
Vol 796 ◽  
pp. 38-45 ◽  
Author(s):  
Omolayo M. Ikumapayi ◽  
Esther Titilayo Akinlabi
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Milling Time ◽  
Coal Fly Ash ◽  
Xrd Analysis ◽  
Morphological Properties ◽  
Particle Sizes ◽  
Pore Size Distributions ◽  
Crystal Phases ◽  
Calcium Iron

In this study, the mechanical disc milling of coal fly ash (CFA) produced by ESKOM thermal station in South Africa has been investigated. The present work covers the effects of milling time on the characteristics such as crystal phases, particle sizes, morphology and physiology of the powder. The produced nanoparticle powders were characterized by SEM-EDX, XRD, and XRF. The milling time was carried out at (t=0, 20, 40, and 60 minutes) at a constant milling speed of 940 rpm. The results showed that mean area of the particles of the particle sizes increased from 75 µm size to approximately 200 nm which revealed that there was 62.5 % increase in the number of particle size as a result of the disintegration of the area of particle sizes. The crystal phases detected by the XRD in CFA are hexagonal, orthorhombic, rhombohedral and anorthic. XRD analysis showed that the most dominant minerals in coal fly ash are Quartz (SiO2), Mullite (Al2.32Si0.68O4.84), Sillimanite (Al2(SiO4)O, Calcite high (CaCO3), Hematite (Fe2O3), Microcline (KAlSi3O8). It was also revealed by EDX that the main elemental compositions present in CFA are silicon, aluminium, calcium, iron, titanium and magnesium. It was established in the study that the duration of the milling affects volume, surface area, particle size, pore size distributions, as well as the microstructure

Nb-W Alloy Prepared by Mechanical Alloying and Optimal Design of Corresponding Milling Variables

2014 ◽  
Vol 1033-1034 ◽  
pp. 839-848
Author(s):  
Bai Ru Li ◽  
Yong Dong Wang ◽  
Xing Liu
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Particle Size ◽  
Milling Time ◽  
Milled Powder ◽  
Orthogonal Test ◽  
Particle Sizes ◽  
Liquid Ratio ◽  
Mechanically Alloyed ◽  
Fe Content

The effects of milling variables on the particle sizes and purity of mechanically alloyed Nb-30W powders were quantitatively investigated using orthogonal test of three factors consisting of milling time A (12h, 24h and 48h), ball-to-powder ratio B (6:1, 10:1 and 20:1) and solid-to-liquid ratio C (1:0.2, 1:0.5 and 1:1) at three levels in order to optimize the milling variables of mechanically alloyed Nb-30W powders. Results indicated that the particle size was mainly determined by the solid-to-liquid ratio and the purity of powder was mainly affected by the ball-to-powder ratio and the milling time; best combination of all variables was found to be A2B2C1 with the particle size 12.62μm and Fe content 0.399%. After hot pressed, A2B2C1 combination obtained the highest mechanical properties. With the refining of particles during milling, the Fe contaminations of milled powder increased and were dissolved into Nb lattices to form Nb (Fe) solid solution; meanwhile, macro stress caused by plastic deformation of Nb particles was released.

Preparation of Barium Titanate Powders by Gel-Solid Reaction

2011 ◽  
Vol 412 ◽  
pp. 473-476 ◽  
Author(s):  
Chun Rong Jiao ◽  
Da Ming Chen ◽  
Jian Feng Tong
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Raw Materials ◽  
Raw Material ◽  
Particle Sizes ◽  
Solid Reaction ◽  
Composite Powders ◽  
Calcination Temperatures ◽  
Large Size ◽  
The One

BaTiO3ceramic composite powders were prepared by a gel-solid reaction method using the raw materials of two particle sizes, DSC was used to study the thermal decomposition of the green body. The effect of the calcination temperatures on the phase structure of the powders was investigated. The influence of the particle sizes of the raw materials on the reaction temperature and the microstructure of the powders was explored. The results showed that reaction temperature of BaTiO3ceramic powders reacted from BaCO3of the large size was about 933.0°C, and the one from BaCO3of the smaller size was about 903.5°C, respectively. XRD results indicated that BaTiO3powders could be prepared at a temperature range of 900°C ~ 1000°C using the raw materials of either size. The particle size of the synthesized powders was determined by the particle size of the raw material. Therefore, the raw materials of small size should be chosen to prepare the synthesized powders of small size, and at a lower reaction temperature.

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