scholarly journals The influence of powder particle size on properties of Cu-Al2O3 composites

2009 ◽  
Vol 41 (2) ◽  
pp. 185-192 ◽  
Author(s):  
V. Rajkovic ◽  
D. Bozic ◽  
M. Popovic ◽  
M.T. Jovanovic
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Grain Size ◽  
Copper Powder ◽  
Average Particle Size ◽  
High Energy ◽  
Average Particle ◽  
Size Refinement ◽  
Al2o3 Particles ◽  
Milled Powders

Inert gas atomized prealloyed copper powder containing 2 wt.% Al (average particle size ? 30 ?m) and a mixture consisting of copper (average particle sizes ? 15 ?m and 30 ?m) and 4 wt.% of commercial Al2O3 powder particles (average particle size ? 0.75 ?m) were milled separately in a high-energy planetary ball mill up to 20 h in air. Milling was performed in order to strengthen the copper matrix by grain size refinement and Al2O3 particles. Milling in air of prealloyed copper powder promoted formation of finely dispersed nano-sized Al2O3 particles by internal oxidation. On the other side, composite powders with commercial micro-sized Al2O3 particles were obtained by mechanical alloying. Following milling, powders were treated in hydrogen at 400 0C for 1h in order to eliminate copper oxides formed on their surface during milling. Hot-pressing (800 0C for 3 h in argon at pressure of 35 MPa) was used for compaction of milled powders. Hot-pressed composite compacts processed from 5 and 20 h milled powders were additionally subjected to high temperature exposure (800?C for 1 and 5h in argon) in order to examine their thermal stability. The results were discussed in terms of the effects of different size of starting powders, the grain size refinement and different size of Al2O3 particles on strengthening, thermal stability and electrical conductivity of copper-based composites.

The Analysis of Microstructure and the Properties of the Metallic-Matrix Composite on the Basis of the Copper and Aluminum Oxide

2015 ◽  
Vol 770 ◽  
pp. 151-155
Author(s):  
Aleksander S. Ivashutenko ◽  
Nikita V. Martyushev ◽  
E.M. Vodopyanov ◽  
Eugene P. Naiden
Keyword(s):  
Particle Size ◽  
Aluminum Oxide ◽  
Copper Powder ◽  
Pure Copper ◽  
Average Particle Size ◽  
Metallic Matrix ◽  
Oxide Powder ◽  
Average Particle ◽  
Aluminum Oxide Powder ◽  
Plasma Sintering

The article is devoted to the analysis of the possibilities to obtain gradient materials by the method of spark plasma sintering. Pure copper powders consisting of particles with the average particle size 100 microns and the nanodispersed powder of aluminum oxide were used in this study. Two powder compositions - pure copper powder and a mixture of copper powder and aluminum oxide powder were sintered:. As a result of the sintering process a sample with a double-area structure has been formed with a well-defined boundary between these areas. After sintering the copper powder porosity remained at the initial level. But having been mixed and sintered, the aluminum oxide powder particles agglomerated up to the average particle size of 80 – 100 microns.

Study on the Microstructure and Properties of ZL205A Alloy under Partial Remelting Treatment

2012 ◽  
Vol 538-541 ◽  
pp. 1183-1186
Author(s):  
Min Li ◽  
Lan Rong Cai ◽  
Peng Xin Liu
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Tensile Strength ◽  
Average Particle Size ◽  
Average Particle ◽  
High Tensile Strength ◽  
Microstructure And Properties ◽  
Partial Remelting ◽  
Average Grain Size ◽  
Zl205a Alloy

In this paper, effects of partial remelting treatment on microstructure and properties of ZL205A alloy were studied in detail. The results show that the grain size of ZL205A alloy decreases at different degree. The grain size increases first and then decreases with increasing of returns content. The average grain size of the primary ZL205A alloy was measured to be about 60 μm, and the good result can be got of the ZL205A alloys with the average particle size of α (Al) phase being about 33 μm after adding 20wt.% returns. The ZL205A alloy with 20 wt.% returns has a considerably high tensile strength and yield strength of 525MPa and 445 MPa, respectively, which is much higher than 501 MPa and 421 MPa of primary ZL205A alloy, meanwhile the elongation level is up to14%.

Effect of Synthetic Technology on the Properties of Co2O3 Powder

2018 ◽  
Vol 281 ◽  
pp. 46-51
Author(s):  
Ge Xiong ◽  
Hui Min Sun ◽  
Xue Yang ◽  
Jin Shi Li ◽  
Mei Hua Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Salt Solution ◽  
Average Particle Size ◽  
Particle Aggregation ◽  
Molar Ratio ◽  
Average Particle

Ultrafine Co2O3powder was prepared via hydrothermal synthesis. The effect of technology on the performance of the superfine Co2O3powders was investigated, and the hydrothermal parameters in preparing Co2O3were gradually improved. In addition, the morphology and grain size of the Co2O3powder were analyzed by FESEM. Results show that reducing the salt–alkali molar ratio resulted in more uniform Co2O3powder and smaller particles, with average particle size of approximately 40 nm. Reaction time displayed little effect on the Co2O3powder, but the particle size decreased with the reaction time. The concentration of salt solution remarkably affected the morphology of the Co2O3powder. Lower concentration resulted in smaller particle aggregation and particle size.

Characterization of Hematite Nanoparticles (Fe2O3) Produced by High Energy Milling for Dye Removal Catalyst

2015 ◽  
Vol 819 ◽  
pp. 423-428
Author(s):  
Roshaida Arbain ◽  
Norlia Baharun
Keyword(s):  
Particle Size ◽  
Textile Industry ◽  
Large Scale ◽  
Average Particle Size ◽  
Industrial Effluent ◽  
High Energy ◽  
Average Particle ◽  
Hematite Nanoparticles ◽  
Grinding Technique ◽  
Remazol Red

Hematite nanoparticles with average particle size of 75.6 and 93.4 nm were produced by mechanical grinding technique using planetary ball mill. The ground hematite were characterized by X-ray diffraction analysis technique, specific surface area analysis (BET), transmission microscope (TEM) and scanning electron microscope (SEM). The effects of different properties of hematite particles used as a catalyst for decolorization of synthetic dye, Remazol Red 3B (RR3B) were investigated. The experimental results show that smaller particle size of 75.6 nm decolourized at the rate of 95.8% within 10 min reaction while larger particle size of 93.4 nm decolorized at the rate of 95.9% within 60 min reaction. The decolorization of RR3B dye by both catalyst were achieved with minimum iron leached (<5 mgL-1) which fulfill the Malaysian Environmental Quality (Industrial Effluent) Regulations 2009. The continuous mode for decolorization of RR3B was carried out and complete decolorization was achieved with low iron dissolution which demonstrates the possibilities of using milled hematite as catalyst for large-scale textile industry wastewater treatment applications.

The Analysis of Microstructure and the Properties of the Metallic-Matrix Composite on the Basis of the Copper and Aluminum Oxide

2015 ◽  
Vol 770 ◽  
pp. 76-80
Author(s):  
Aleksander S. Ivashutenko ◽  
Nikita V. Martyushev ◽  
E.M. Vodopyanov ◽  
Valeriy P. Bezborodov
Keyword(s):  
Particle Size ◽  
Aluminum Oxide ◽  
Copper Powder ◽  
Pure Copper ◽  
Average Particle Size ◽  
Metallic Matrix ◽  
Oxide Powder ◽  
Average Particle ◽  
Aluminum Oxide Powder ◽  
Plasma Sintering

The article is devoted to the analysis of the possibilities to obtain gradient materials by the method of spark plasma sintering. Pure copper powders consisting of particles with the average particle size 100 microns and the nanodispersed powder of aluminum oxide were used in this study. Two powder compositions - pure copper powder and a mixture of copper powder and aluminum oxide powder were sintered:. As a result of the sintering process a sample with a double-area structure has been formed with a well-defined boundary between these areas. After sintering the copper powder porosity remained at the initial level. But having been mixed and sintered, the aluminum oxide powder particles agglomerated up to the average particle size of 80 – 100 microns.

Non-template synthesis of titania hollow spheres and their thermal stability

2005 ◽  
Vol 20 (4) ◽  
pp. 796-800 ◽  
Author(s):  
Xin M. Wang ◽  
Ping Xiao
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Phase Stability ◽  
Template Synthesis ◽  
Anatase Phase ◽  
Average Particle Size ◽  
Hollow Spheres ◽  
Average Particle ◽  
Spherical Structure ◽  
Scale Preparation

Uniform and thermally stable spherical titania particles with hollow interiors were directly prepared by a novel solvothermal precipitation of TiCl4 in isopropanol without templates or shape-controller reagents. An average particle size of 700 nm to 1 μm was obtained. The hollow spheres consisted of pure anatase phase nanocrystals with an estimated crystallite size of 12–15 nm. Upon heating, the pure anatase phase was retained for temperatures up to 800 °C, which suggested that the spherical structure contributed to phase stability. This method is a promising process for industrial-scale preparation of titania hollow spheres.

Effect of VC/Cr3C2 Additions on Microstructure and Mechanical Properties of WC-16TiC-XTaC-10Co Ultrafine Cemented Carbides

2012 ◽  
Vol 476-478 ◽  
pp. 1214-1217 ◽  
Author(s):  
Chong Cai Zhang ◽  
Quan Wang ◽  
Qun Qun Yuan ◽  
Long Wang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Ball Milling ◽  
Rupture Strength ◽  
Average Particle Size ◽  
High Energy ◽  
Cemented Carbides ◽  
Average Particle ◽  
Hardness Increase ◽  
Energy Ball

In this paper, the WC-16TiC-xTaC-10Co mixture mixed by WC 0.52μm, (W, Ti, Ta)C 2.9μm and Co1.36μm and prepared by high-energy ball milling, changed the VC and Cr3C2 adding amount. After ball milling for 60 hours, an average particle size of 220nm powder was prepared and it was cold isostatic pressed at 300MPa and vacuum sintered at 1410°C. The physical properties and the micrographs of samples were detected. The main conclusions are as follow: the coercivity and hardness increase and Cobalt magnetic decreases with the content of Cr3C2 increasing, the transverse rupture strength (TRS) does not vary. The VC and Cr3C2 inhibit the growth of WC grain, but can’t inhibite the (W, Ti, Ta)C grain growth effectively.

scholarly journals NANOENKAPSULASI ASAM STEARAT DENGAN MODIFIKASI GRAFENA mG/SA WALL-CORE SEBAGAI KOMPOSIT PERUBAHAN FASA

2020 ◽  
Vol 8 (1) ◽  
pp. 53
Author(s):  
Saharman Gea ◽  
Vivi Purwandari
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Particle Size ◽  
Average Particle Size ◽  
Active Phase ◽  
Stable Form ◽  
Average Particle ◽  
Effective Protection ◽  
Excellent Thermal Stability ◽  
Modified Graphene

The fabrication of phase-changed composite (PCC) utilized to store thermal energy through encapsulation has been performed by utilizing the stearate acid (SA) and modified graphene (mG) with sentrimoinum bromide (CTAB). The composite was fabricated via latex method, while the liquid SA was able to be encapsulated and stabilized due to the presence of mG. The active phase of SA altered to be a thermal storing site obtained from latent heat, while the mG wall has protective features which can prevent the leakage of SA core during the transition phase. The active phase itself increased the thermal conductivity from 4.93 W/mK to 7.65 W/mK with maximum storing energy for 84.8%. The stable form of mG was measured extremely low for 2 phr with an average particle size of 13.68 nm. Thus, mG wall has excellent thermal stability and effective protection in shielding the SA core which improves the thermal properties of the composite.

scholarly journals Mechanochemical synthesis and consolidation of nanostructured cerium hexaboride

2019 ◽  
Vol 13 (1) ◽  
pp. 32-43 ◽  
Author(s):  
Duygu Ağaoğulları ◽  
Özge Balcı ◽  
Nazlı Akçamlı ◽  
Challapalli Suryanarayana ◽  
İsmail Duman ◽  
...  
Keyword(s):  
Particle Size ◽  
Electrical Resistivity ◽  
Mechanochemical Synthesis ◽  
High Purity ◽  
Average Particle Size ◽  
High Energy ◽  
Wear Behaviour ◽  
Size Analysis ◽  
Average Particle ◽  
Scanning Calorimetry

This study reports on the mechanochemical synthesis (MCS) and consolidation of nanostructured CeB6 powders of high purity. CeB6 powders were prepared via MCS by milling CeO2, B2O3 and Mg powders in a high-energy ball mill for different milling times. The effects of milling time on the formation, microstructure and thermal behaviour of the synthesized powders were investigated and the optimum MCS duration was determined. Purified powders were obtained after HCl leaching by removing MgO by-product. The prepared powders were characterized by a number of techniques including X-ray diffraction, stereomicroscopy, scanning and transmission electron microscopy coupled with energy dispersive spectrometry, differential scanning calorimetry, atomic absorption spectrometry, particle size analysis, surface area analysis and vibrating sample magnetometry. The high-purity CeB6 powders having an average particle size of 86 nm were consolidated by cold-pressing followed by pressureless sintering at 1700 ?C for 5 h. The bulk CeB6 specimen was investigated for its microstructure, density, electrical resistivity, surface roughness and some mechanical properties (microhardness and wear behaviour). The relative density, electrical resistivity, microhardness and wear rate of the bulk CeB6 were determined as 95.2%TD, 57.50 ?W?cm, 11.65GPa and 1.46 ? 10?4 mm3/N?m, respectively.

Production of BaTiO2 Nanocrystalline Powders by High Energy Milling and Piezoelectric Properties of Corresponding Ceramics

2013 ◽  
Vol 547 ◽  
pp. 133-138
Author(s):  
K. Chandramani Singh ◽  
Chongtham Jiten
Keyword(s):  
Particle Size ◽  
Piezoelectric Properties ◽  
Average Particle Size ◽  
Hysteresis Loops ◽  
Functional Materials ◽  
High Energy ◽  
Nanocrystalline Powders ◽  
Average Particle ◽  
Ceramic Samples ◽  
Energy Ball

Barium titanate (BaTiO3 or BT) has become one of the most studied functional materials due to its potential application as multilayer ceramic capacitors, PTC thermistors, electromechanical devices, piezoelectric transducers, actuators, dynamic RAM or logic circuitry as well as a great variety of electro-optical devices. In the present study, high energy ball milling has been used to produce nanocrystalline powders of BT. Two categories of powders having average particle size of 35 nm and 25 nm were prepared by setting the milling speed at 250 rpm and 300 rpm respectively, fixing the milling time at 30 hours. Four ceramic samples, BT35-1350, BT25-1350, BT35-1400 and BT25-1400, were formed by sintering the two types of powders at 1350oC and 1400oC for 3 hours. The ferroelectric and piezoelectric properties of the ceramic samples were studied and found to be dependent on the size of the starting nanopowders. The bulk density and piezoelectric constant (d33) of B25-1350 were found to be less than those of BT35-1350, while the reverse was true in case of BT25-1400 and BT35-1400. Well saturated P-E hysteresis loops were observed for all the ceramics with the size and shape of the loops appearing different for the four samples. For both the pairs of ceramics sintered at 1350oC and 1400oC, the remnant polarization (Pr) decreases with starting particle size, that is, as we go from BT35-1350 to BT25-1350 as well as from BT35-1400 to BT25-1400. However, with decreasing particle size of the starting powders, the coercive field (Ec) increases for the ceramics sintered at 1350oC and decreases for the ceramics sintered at 1400oC. The study reveals the importance of an optimized combination of the size of the starting nanopowders and sintering temperature for obtaining BT ceramics with the desired properties.

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