scholarly journals Effect of Electric Current on SPS Densification of Spherical Copper Powder

2021 ◽  
Vol 5 (4) ◽  
pp. 119
Author(s):  
Romaric Collet ◽  
Sophie Le Gallet ◽  
Frédéric Charlot ◽  
Sabine Lay ◽  
Jean-Marc Chaix ◽  
...  
Keyword(s):  
Electric Current ◽  
Copper Powder ◽  
Pure Copper ◽  
Joule Effect ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Significant Temperature ◽  
Two Parameters ◽  
A Current

When a current is involved, as in spark plasma sintering, metallic powders are heated by the Joule effect through both tool and specimen. Other mechanisms might occur, but it is difficult to separate the role of the temperature from the role of the current inside the sample as, in most cases, the two parameters are not controlled independently. In this paper, the consolidation and the densification of a pure copper powder were studied in three configurations for obtaining different electric current paths: (i) current flowing through both the powder and the die, (ii) current forced into the powder and (iii) no current allowed in the powder. Electrical conductivity measurements showed that even low-density samples displayed higher conductivities than graphite by several orders of magnitude. FEM simulations confirmed that these copper specimens were mainly heated by the graphite punches. No modification of the microstructure by the flow of current could be observed. However, the absence of current in the specimen led to a decrease in densification. No significant temperature difference was modeled between the configurations, suggesting that differences are not linked to a thermal cause but rather to a current effect.

scholarly journals Electric Current-Assisted Joining of Copper Plates Using Silver Formed by In-Situ Decomposition of Ag2C2O4

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 538 ◽  
Author(s):  
Dina Dudina ◽  
Alexander Matvienko ◽  
Anatoly Sidelnikov ◽  
Mikhail Legan ◽  
Vyacheslav Mali ◽  
...  
Keyword(s):  
Shear Strength ◽  
Electric Current ◽  
Reference Sample ◽  
Silver Layer ◽  
Metallic Silver ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
In Situ Decomposition

Pulsed electric current can be used for the fast sintering of powders as well as joining of macroobjects. In this work, we brazed copper plates using a silver layer that was formed in situ by the decomposition of a silver oxalate Ag2C2O4 powder placed between the plates. Joining was conducted in the chamber of a Spark Plasma Sintering (SPS) facility with and without a graphite die. In the die-assisted tooling configuration, indirect heating of the assembly from the graphite die carrying electric current occurred until the brazing layer transformed into metallic silver. The passage of electric current through a Cu/Ag2C2O4/Cu stack placed between the electrodes without a die was possible because of the formation of Cu/Cu contacts in the areas free from the Ag2C2O4 particles. Joints that were formed in the die-assisted experiments showed a slightly higher shear strength (45 MPa) in comparison with joints formed without a die (41 MPa). The shear strength of the reference sample (obtained without a die), a stack of copper plates joined without any brazing layer, was only 31 MPa, which indicates a key role of the silver in producing strong bonding between the plates. This study shows that both die-assisted tooling configurations and those without a die can be used for the SPS brazing of materials by the oxalate-derived silver interlayer.

Preparing Magnetocaloric LaFeSi Uniform Microstructures by Spark Plasma Sintering

2014 ◽  
Vol 802 ◽  
pp. 491-495
Author(s):  
N. Vicente ◽  
J. Ocanã ◽  
H.N. Bez ◽  
C.S. Teixeira ◽  
Izabel Fernanda Machado ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electric Current ◽  
Spark Plasma Sintering ◽  
Joule Effect ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Vicker’S Microhardness ◽  
Scanning Electron

Spark Plasma Sintering (SPS) of LaFeSi alloy powders was conducted to prepare magnetocaloric La-Fe-Si-based uniform microstructures. Two electrically insulating discs made of alumina were interposed between the punches and powder sample inhibiting the flow of electric current across the powder. This approaching aiming at improving the sample temperature distribution by deviating the electric current throughout the graphite die, since the electric current induces overheating byin situJoule effect on powder. The LaFeSi powder with particles under 150 µm was obtained by mechanical milling of particles from hydrogenated and decrypted casting ingot. The characterizations of sintered samples were performed by Scanning Electron Microscopy (SEM), Archimedes principle, Vicker’s hardness and microhardness. The uniformity of the microstructure was evaluated by checking the evidence of position on the Vicker’s microhardness by means of ANOVA statistics.

scholarly journals On the Role of the Electrical Field in Spark Plasma Sintering of UO2+x

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Vaclav Tyrpekl ◽  
Mohamed Naji ◽  
Michael Holzhäuser ◽  
Daniel Freis ◽  
Damien Prieur ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Electrical Field ◽  
Plasma Sintering ◽  
Spark Plasma

The influence of the local effect of electric current on densification of tungsten powder during spark plasma sintering

2019 ◽  
Vol 356 ◽  
pp. 769-777 ◽  
Author(s):  
Shenghua Deng ◽  
Hongjin Zhao ◽  
Ruidi Li ◽  
Tiechui Yuan ◽  
Lanbo Li ◽  
...  
Keyword(s):  
Electric Current ◽  
Spark Plasma Sintering ◽  
Tungsten Powder ◽  
Local Effect ◽  
Plasma Sintering ◽  
Spark Plasma

Effect of Zr and C co-addition on the characteristics of ZrB2-based ceramics: Role of spark plasma sintering temperature

2020 ◽  
Vol 46 (16) ◽  
pp. 24975-24985 ◽  
Author(s):  
Behzad Nayebi ◽  
Nader Parvin ◽  
Jamshid Aghazadeh Mohandesi ◽  
Mehdi Shahedi Asl
Keyword(s):  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Co Addition

Enhanced electrical properties of ZnO varistor ceramics by spark plasma sintering: Role of annealing

2020 ◽  
Vol 46 (10) ◽  
pp. 15076-15083 ◽  
Author(s):  
Jie Liang ◽  
Xuetong Zhao ◽  
Jianjie Sun ◽  
Lulu Ren ◽  
Ruijin Liao ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Spark Plasma Sintering ◽  
Zno Varistor ◽  
Plasma Sintering ◽  
Spark Plasma

Enhanced electrical properties of CaCu3Ti4O12 ceramics by spark plasma sintering: Role of Zn and Al co-doping

2019 ◽  
Vol 792 ◽  
pp. 1079-1087 ◽  
Author(s):  
Chao Xu ◽  
Xuetong Zhao ◽  
Lulu Ren ◽  
Jianjie Sun ◽  
Lijun Yang ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Spark Plasma Sintering ◽  
Co Doping ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Role Of Zn

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.

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