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

• Published in: Metals (Basel ) Vol. 8; no. 7; p. 538
• Main Authors: Dudina, Dina, Matvienko, Alexander, Sidelnikov, Anatoly, Legan, Mikhail, Mali, Vyacheslav, Esikov, Maksim, Anisimov, Alexander, Gribov, Pavel, Boldyrev, Vladimir
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-07-2018
• Subjects: Bonding strength; Brazing; Configurations; Conflicts of interest; Copper; Decomposition; Electric contacts; electric current; Electric currents; Experiments; Geometry; Graphite; Interfacial bonding; Interlayers; Joining; Metal plates; Morphology; Nanoparticles; Plasma sintering; Porous materials; Shear strength; Silver; silver oxalate; Spark Plasma Sintering; Tooling; Russia
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met8070538

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.