Nickel-Graphite Composites of Variable Architecture by Graphitization-Accompanied Spark Plasma Sintering and Hot Pressing and their Response to Phase Separation

  • D. V. Dudina Institute of Solid State Chemistry and Mechanochemistry SB RAS; Novosibirsk State University
  • A. V. Ukhina Institute of Solid State Chemistry and Mechanochemistry SB RAS
  • B. B. Bokhonov Institute of Solid State Chemistry and Mechanochemistry SB RAS; Novosibirsk State University
  • V. I. Mali Lavrentiev Institute of Hydrodynamics SB RAS
  • A. G. Animisov Lavrentiev Institute of Hydrodynamics SB RAS
  • N. V. Bulina Institute of Solid State Chemistry and Mechanochemistry SB RAS
  • I. N. Skovorodin Institute of Automation and Electrometry SB RAS

Abstract

We report the formation and phase separation response of nickel-graphite composites with variable-architecture phases by graphitization-accompanied consolidation via Spark Plasma Sintering and hot pressing. It was shown that the application of pressure during consolidation is crucial for the occurrence of graphitization and formation of 3D graphite structures. We evaluated the suitability of the synthesized composites as precursors for making porous structures. Nickel behaved as a space holder with the particle size and spatial distribution changing during consolidation with the temperature and determining the structure of porous graphite formed by phase separation by dissolution in HCl. The response of the consolidated Ni-Cgr to separation of carbon by its burnout in air was studied. The result of the carbon removal was either the formation of a dense and continuous NiO film on the surface of the compacts or oxidation through the compact thickness. The choice between these two options depended on the density of the compacts and on the presence of carbon dissolved in nickel. It was found that during the burnout of graphite from Ni-Cgr composites, sintering, rather than formation of pores, dominated.

Published
2017-12-13
Issue
Vol 47 No 3 (2015)
Section
Articles

Copyright 

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