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.

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.

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.

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.

Structural Evolution in the Processing of Fe/ BaFe12O19 Nano Composite via Mechanical Alloying

2008 ◽  
Vol 55-57 ◽  
pp. 569-572
Author(s):  
Abolghasem Ataie ◽  
R. Nikkhah-Moshaie
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Milling Time ◽  
Magnetic Phase ◽  
Sol Gel ◽  
Barium Hexaferrite ◽  
Combustion Method ◽  
Magnetic Composite ◽  
Phase Constitution ◽  
Mean Particle Size

Barium hexaferrite particles derived from sol-gel combustion method with a mean particle size of 160 nm and Fe particles with a mean particle size of 150 µm were mechanically alloyed using planetary ball mill. Phase constitution and EDS analysis of the products were investigated by XRD and SEM, respectively. Magnetic properties of samples were measured by VSM. Influence of the milling time and Fe content on the phase constitution of synthesized composites has been investigated. XRD results indicated that in sample with 90 and 50wt% Fe, the magnetic composite with enhanced magnetic properties, formed based on Fe phase while barium hexaferrite particles embedded within Fe particles. In sample with 90% Fe, the crystallite size of Fe reduced from 173 to 87 nm by increasing the milling time from 1 to 20 h; saturation magnetization of the 20 h milled sample was measured as 94.8 emu/g. Besides, in sample with 50wt% Fe, some FeO phase was detected which is probably due to the partial decomposition of hard magnetic phase during milling. Sample with 10wt% Fe showed completely different behavior and magnetite appeared as a major magnetic phase.

Nanostructured Polymetallic Powders to Create New Functional Materials on its Base

2015 ◽  
Vol 670 ◽  
pp. 49-54 ◽  
Author(s):  
Yuriy A. Zaharov ◽  
Valeriy M. Pugachev ◽  
Kseniya A. Datiy ◽  
Anna N. Popova ◽  
Anastasiya S. Valnyukova ◽  
...  
Keyword(s):  
Particle Size ◽  
Phase Diagrams ◽  
Spatial Organization ◽  
Functional Materials ◽  
Particle Morphology ◽  
Cloud Type ◽  
Synthesis Conditions ◽  
Micron Size ◽  
Common Nature ◽  
20 Nm

In the paper, the particle morphology is considered and the slices of phase diagrams of nanosystems agreeable to the synthesis conditions are constructed according to the data obtained earlier by authors, as well as new results of the study of nanostructured Fe-Co, Fe-Ni, Co-Ni, Fe-Co-Ni, Fe-Pt, Cu-Ni and Ni-Cd powders. It is found that all considered polymetallic systems have common nature of the particle size spatial organization, i.e., 7-20 nm nanocrystals (for different systems) form highly compact aggregates (40-100 nm) which put together into loose porous agglomerates (up to 200-250 nm) and then into unconsolidated micron size formation of cloud type. It is classified uncovered features of nanostructured polymetallic phase diagrams in comparison with phase diagrams of bulk systems. Magnetic properties of nanosystems are studied.

scholarly journals Particle Size Effect of Lanthanum-Modified Bismuth Titanate Ceramics on Ferroelectric Effect for Energy Harvesting

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Sangmo Kim ◽  
Thi My Huyen Nguyen ◽  
Rui He ◽  
Chung Wung Bark
Keyword(s):  
Particle Size ◽  
Energy Harvesting ◽  
High Speed ◽  
High Performance ◽  
Bismuth Titanate ◽  
Vinylidene Fluoride ◽  
Piezoelectric Materials ◽  
Renewable Energy Sources ◽  
Particle Size Effect ◽  
Ferroelectric Materials

AbstractPiezoelectric nanogenerators (PNGs) have been studied as renewable energy sources. PNGs consisting of organic piezoelectric materials such as poly(vinylidene fluoride) (PVDF) containing oxide complex powder have attracted much attention for their stretchable and high-performance energy conversion. In this study, we prepared a PNG combined with PVDF and lanthanum-modified bismuth titanate (Bi4−XLaXTi3O12, BLT) ceramics as representative ferroelectric materials. The inserted BLT powder was treated by high-speed ball milling and its particle size reduced to the nanoscale. We also investigated the effect of particle size on the energy-harvesting performance of PNG without polling. As a result, nano-sized powder has a much larger surface area than micro-sized powder and is uniformly distributed inside the PNG. Moreover, nano-sized powder-mixed PNG generated higher power energy (> 4 times) than the PNG inserted micro-sized powder.

Hydrogen Generation by Hydrolysis of the Ball Milled Al-C-KCl Composite Powder in Distilled Water

2012 ◽  
Vol 519 ◽  
pp. 87-91 ◽  
Author(s):  
Xia Ni Huang ◽  
Zhang Han Wu ◽  
Ke Cao ◽  
Wen Zeng ◽  
Chun Ju Lv ◽  
...  
Keyword(s):  
Particle Size ◽  
Reaction Temperature ◽  
Fine Particle ◽  
Composite Powder ◽  
Hydrogen Generation ◽  
Aluminum Particle ◽  
Generation Rate ◽  
Composite Powders ◽  
Fine Particle Size ◽  
Hydrolysis Of

In the present investigation, the Al-C-KCl composite powders were prepared by a ball milling processing in an attempt to improve the hydrogen evolution capacity of aluminum in water. The results showed that the hydrogen generation reaction is affected by KCl amount, preparation processing, initial aluminum particle size and reaction temperature. Increasing KCl amount led to an increased hydrogen generation volume. The use of aluminum powder with a fine particle size could promote the aluminum hydrolysis reaction and get an increased hydrogen generation rate. The reaction temperature played an important role in hydrogen generation rate and the maximum hydrogen generation rate of 44.8 cm3 min-1g-1of Al was obtained at 75oC. The XRD results identified that the hydrolysis byproducts are bayerite (Al(OH)3) and boehmite (AlOOH).

Development of Ni/h-BN Self-Lubricating Composite Powder by High-Energy Ball Milling

2016 ◽  
Vol 869 ◽  
pp. 277-282
Author(s):  
Moisés Luiz Parucker ◽  
César Edil da Costa ◽  
Viviane Lilian Soethe
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Solid Lubricants ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Second Phase ◽  
Average Particle ◽  
Composite Powders ◽  
The Matrix ◽  
Energy Ball

Solid lubricants have had good acceptance when used in problem areas where the conventional lubricants cannot be applied: under extreme temperatures, high charges and in chemically reactive environments. In case of materials manufactured by powder metallurgy, particles of solid lubricants powders can be easily incorporated to the matrix volume at the mixing stage. In operation, this kind of material provides a thin layer of lubricant that prevents direct contact between the surfaces. The present study aimed at incorporating particles of second phase lubricant (h-BN) into a matrix of nickel by high-energy ball milling in order to obtain a self-lubricating composite with homogeneous phase distribution of lubricant in the matrix. Mixtures with 10 vol.% of h-BN varying the milling time of 5, 10, 15 and 20 hours and their relationship ball/powder of 20:1 were performed. The effect of milling time on the morphology and microstructure of the powders was studied by X-ray diffraction, SEM and EDS. The composite powders showed reduction in average particle size with increasing milling time and the milling higher than 5 hours resulted in equiaxial particles and the formation of nickel boride.

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