scholarly journals Physical modeling of representative particles of electrodeposited copper powders

2006 ◽  
Vol 71 (4) ◽  
pp. 397-400 ◽  
Author(s):  
Konstantin Popov ◽  
Nebojsa Nikolic ◽  
Snezana Krstic ◽  
Miomir Pavlovic
Keyword(s):  
Cross Sections ◽  
Copper Powder ◽  
Physical Modeling ◽  
Copper Powders

A method for the estimation of the size of the representative particle of a copper powder is given. Cross sections of representative particles of flowing and non-flowing powders estimated by this procedure are also presented.

Expansion Behavior of Iron-Copper Compact from (FeCu) Pre-Alloyed Powder

2007 ◽  
Vol 534-536 ◽  
pp. 517-520
Author(s):  
Youn Che Kim ◽  
Myung Jin Suk
Keyword(s):  
Copper Powder ◽  
Copper Content ◽  
Liquid Copper ◽  
Alloyed Powder ◽  
Maximum Expansion ◽  
Iron Copper ◽  
Expansion Behavior ◽  
Expansion Mechanism ◽  
Copper Powders ◽  
Powder Content

Dilatometric curves of iron-copper compact made from elemental or pre-alloyed powder were compared in order to study its expansion mechanism. The compacts from a mixture of elemental iron and copper powders showed the maximum expansion at the copper powder content of 7.44mass% and at the sintering temperatures above the copper melting-point. In the case of the compacts from a mixture of iron pre-alloyed powder of (Fe- 3.44mass%Cu) and copper powder, the maximum expansion which is lower than the former case was obtained at the additive copper powder content of 4.00mass%. But the compact from a mixture of iron pre-alloyed powder of (Fe-7.18mass%Cu) and copper powder showed only shrinkages at any additive copper powder content. The penetration of liquid copper into the interstices between solid grains was observed in all sintered compacts. The iron-copper compacts containing the same content of copper powder showed a very different expansion behavior depending on the amount of copper content in the starting iron raw powder.

scholarly journals Metallographical Aspects of the Application of Special Paint Layers for the Protection of Machine Part Sections against the Effect of lonitriding

2019 ◽  
Vol 290 ◽  
pp. 03002
Author(s):  
Marius Bibu ◽  
Florin Ciofu
Keyword(s):  
Copper Powder ◽  
Machine Part ◽  
Plasma Nitriding ◽  
Metallic Component ◽  
Copper Powders ◽  
Ionic Nitriding ◽  
Local Protection ◽  
Before And After ◽  
Gas Volume ◽  
Physical And Chemical

The paper presents aspects concerning the appreciation of the protection through special paints based on copper powders used against plasma nitriding. First of all the choice of copper is motivated as an important metallic component of protecting paints, with the characteristics that the copper presents in the context of the physical and chemical phenomena (from the cathode and from gas volume) specific for the ionic nitriding process. The paper contains comparatively some characteristics (the duration of drying on the coat, the compatibility of the components, the capacity of extension and of avoiding the leakage, the power of covering, the capacity of joining, and the emitting of gases, the resistance in friction before and after the ionic nitriding, the way of obtaining the copper powder and its quality, the capacity of removing after ionic nitriding etc.) of the mixtures, for the protection against ionic nitriding. Following the researches on making more efficient technologies of local protection of metal pieces on certain areas with isolated layers against plasma nitride, the authors realized 2 different kinds of special original paints noted V-1 and V-2 used for this purpose. These paints are made having a basis of copper powder combined with magnesium oxide and polystiren dissolved in carbon chloride.

scholarly journals The apparent density as a function of the specific surface of copper powder and the shape of the particle size distribution curve

2003 ◽  
Vol 68 (11) ◽  
pp. 903-907 ◽  
Author(s):  
Konstantin Popov ◽  
Predrag Zivkovic ◽  
Snezana Krstic
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Specific Surface ◽  
Size Distribution ◽  
Apparent Density ◽  
Copper Powder ◽  
Distribution Curve ◽  
Particle Size Distribution Curve ◽  
Sulfate Solutions ◽  
Copper Powders

The relation between the specific surface and apparent density of copper powders electrodeposited from acid copper sulfate solutions is established. It is shown that the apparent density is inversely proportional to the specific surface of copper powder. The shape of the particle size distribution curve is also discussed.

Side‐looking underground radar (SLUR): Physical modeling and case history

Geophysics ◽  
1998 ◽  
Vol 63 (6) ◽  
pp. 1925-1932 ◽  
Author(s):  
Jeffrey J. Daniels ◽  
James Brower
Keyword(s):  
Cross Sections ◽  
Ground Penetrating Radar ◽  
Physical Modeling ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Plan View ◽  
Different Depths ◽  
Ground Penetrating ◽  
Oriented Object ◽  
Horizontal Layers

A modification of conventional surface ground‐penetrating radar (GPR) was conceived, tested, and successfully applied in the field at Brookhaven National Laboratory (BNL) to investigate waste pits. The modified GPR method consists of making measurements along a traverse line in a sloping trench with the radar’s antenna oriented at an angle of up to 45° from the horizontal. The direction of propagation of the electromagnetic field for this configuration is not vertical, and the amount of energy scattered from objects that are oriented vertically relative to the energy scattered from horizontal layers is increased. This fundamental feature of side‐looking underground radar (SLUR) measurements is illustrated by physical modeling. Measurements made along parallel trenches that are offset at different distances from a vertically oriented object provides GPR cross‐sections with a primary plane of investigation that intersects the vertical feature at different depths. SLUR was used at BNL in conjunction with conventional surface GPR measurements (displayed as 3-D blocks and plan‐view time slices) to enhance the vertical definition and improve the depth estimates of the waste pits.

scholarly journals Testing of Sinters Made of Copper Powders Coated with Carbon Structure Containing Graphene

2021 ◽  
Vol 12 (2) ◽  
pp. 75-90
Author(s):  
Kamil RAJKOWSKI ◽  
Tomasz MAJEWSKI
Keyword(s):  
Powder Mixture ◽  
Copper Powder ◽  
Brinell Hardness ◽  
Optical Microscope ◽  
Cold Isostatic Pressing ◽  
Powder Mixtures ◽  
Copper Powders ◽  
Tap Density ◽  
Process Measurements ◽  
Made In

This paper presents the results of preliminary tests on specimens made from mixtures of dendritic copper powder (CuE) with the graphene-coated copper powder (CuG) in a range from 20% to 100% (CuG). The properties of the powder mixtures, green compacts and sinters were determined. To study the properties of the powder mixtures, the following tests were carried out: a measurement of the CuG powder grain size after the grinding process, measurements of the bulk density and tap density of the prepared powder mixtures. The porosity of the produced green compacts and the sinters was calculated as well as the densification capabilities of the powder mixtures by die pressing, cold isostatic pressing and sintering in a reducing atmosphere were tested. Moreover, the nature of the porosity formation was analysed using an optical microscope and the Brinell hardness was determined. The measured Brinell hardness was in the range of 17 HB for sinters made from CuG to 34 HB for sinters made from a 20% CuG powder mixture. More than six hundred measurements that were made in this study show that the high CuG content in the powder mixture reduce the hardness of the sinters as well increase their porosity.

scholarly journals Characteristics and Processing of Hydrogen-Treated Copper Powders for EB-PBF Additive Manufacturing

2019 ◽  
Vol 9 (19) ◽  
pp. 3993 ◽  
Author(s):  
Christopher Ledford ◽  
Christopher Rock ◽  
Paul Carriere ◽  
Pedro Frigola ◽  
Diana Gamzina ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Grain Boundaries ◽  
Oxygen Content ◽  
Copper Powder ◽  
High Purity ◽  
High Speed ◽  
Track Width ◽  
Copper Powders ◽  
Initial Oxygen ◽  
Purity Copper

The fabrication of high purity copper using additive manufacturing has proven difficult because of oxidation of the powder feedstock. Here, we present work on the hydrogen heat treatment of copper powders for electron beam powder bed fusion (EB-PBF), in order to enable the fabrication of high purity copper components for applications such as accelerator components and vacuum electronic devices. Copper powder with varying initial oxygen contents were hydrogen heat-treated and characterized for their chemistry, morphology, and microstructure. Higher initial oxygen content powders were found to not only reduce surface oxides, but also reduce oxides along the grain boundaries and form trapped H2O vapor inside the particles. The trapped H2O vapor was verified by thermogravimetric analysis (TGA) and residual gas analysis (RGA) while melting. The mechanism of the H2O vapor escaping the particles was determined by in-situ SEM heated stage experiments, where the particles were observed to crack along the grain boundaries. To determine the effect of the EB-PBF processing on the H2O vapor, the thermal simulation and the validation of single melt track width wafers were conducted along with melting single layer discs for chemistry analysis. A high speed video of the EB-PBF melting was performed in order to determine the effect of the trapped H2O vapor on the melt pool. Finally, solid samples were fabricated from hydrogen-treated copper powder, where the final oxygen content measured ~50 wt. ppm, with a minimal residue hydrogen content, indicating the complete removal of trapped H2O vapor from the solid parts.

Characterizations of Plating Structures and Electromagnetic Shielding Properties of the Micron-Sized Flaky Silver-Coated Copper Powder

2011 ◽  
Vol 217-218 ◽  
pp. 321-325 ◽  
Author(s):  
Deng Gao Guan ◽  
Chuan Min Sun ◽  
Jin Hui Lin ◽  
Yao Sun ◽  
Guan Li Xu ◽  
...  
Keyword(s):  
Copper Powder ◽  
Composite Coatings ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Copper Powders ◽  
Study Results ◽  
Plating Method ◽  
Shielding Properties ◽  
Electroless Silver Plating ◽  
Coating Layer Thickness

A new kind of the micron-sized flaky silver-coated copper powder was prepared by electroless silver plating in this paper. Its plating structures were characterized by XRD, SEM and EDS. And a new kind of the electromagnetic shielding composite coatings containing 60 wt% the micron-sized flaky silver-coated copper powders and 40 wt% epoxy resin was prepared. Its electromagnetic shielding properties were analyzed by coaxial transmission line equipment. The study results show the micron-sized flaky silver-coated copper powders are composed of 91.35 wt% Cu and 8.65 wt% Ag and have high width-thickness ratio and crystal structure characteristics. In the frequency range of 0.3-1000 MHz, the shielding effectiveness of the coatings is up to 70.15-77.46 dB and increased an average of 22.18 dB compared with the coatings containing 60 wt% micron-sized flaky copper powders when the coating layer thickness is 300 μm. It is seen that the electroless silver plating method effectively improves the inoxidizability, conductivity and electromagnetic shielding properties of copper powders.

scholarly journals The effect of reversing current deposition on the apparent density of electrolytic copper powder

2002 ◽  
Vol 67 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Konstantin Popov ◽  
Ljubica Pavlovic ◽  
Evica Ivanovic ◽  
Velimir Radmilovic ◽  
Miomir Pavlovic
Keyword(s):  
Apparent Density ◽  
Copper Powder ◽  
Particle Morphology ◽  
Electrolytic Copper ◽  
Current Wave ◽  
Electrolytic Copper Powder ◽  
Copper Powders ◽  
Morphology And Structure ◽  
Powder Particles

The possibility of depositing copper powders with different apparent density by changing the shape of reversing current wave is shown. The morphology and crystallinity of powder particles can be varied considerably by changing shape of the reversing current wave and, hence, the apparent density of powders. The relation of apparent density with particle morphology and structure was illustrated.

scholarly journals The effect of particle structure on apparent density of electrolytic copper powder

2001 ◽  
Vol 66 (11-12) ◽  
pp. 923-933 ◽  
Author(s):  
M.G. Pavlovic ◽  
Lj.J. Pavlovic ◽  
E.R. Ivanovic ◽  
V. Radmilovic ◽  
K.I. Popov
Keyword(s):  
Apparent Density ◽  
Copper Powder ◽  
Metallic Copper ◽  
Microstructural Analysis ◽  
Sieve Analysis ◽  
Particle Structure ◽  
Copper Powders ◽  
Electron Microscopy Analysis ◽  
Powder Particles ◽  
The Difference

The quantitative microstructural analysis and the sieve analysis of copper powder as well as the scanning electron microscopy analysis of the copper powders particles were performed. It was found that the structure of the copper powder particles determines the apparent density of copper powder. The powder particles from the same fractions of different powders occupy approximately the same volume, but the structure of metallic copper is very different. This causes the difference in apparent densities of copper powder obtained under different conditions. The more dendritic is the structure of powder particles the smaller is the apparent density of copper powder.

scholarly journals The representative particle of copper powder and branch of copper dendrites

2002 ◽  
Vol 67 (12) ◽  
pp. 861-866 ◽  
Author(s):  
Konstantin Popov ◽  
Nebojsa Nikolic ◽  
Zlatko Rakocevic
Keyword(s):  
Specific Surface ◽  
Apparent Density ◽  
Powder Particle ◽  
Copper Powder ◽  
Copper Powders ◽  
Electrochemically Deposited ◽  
Size And Morphology

Electrochemically deposited copper powders, which are formed of particles of different size and morphology, are characterized by some properties like specific surface and apparent density. Aprocedure of the determination of a representative powder particle, exhibiting the same values of specific surface and apparent density as the powder is proposed. The proposed procedure also permints an explanation of the branching of copper dendrites.

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