Graphite encapsulated nanocrystals produced using a low carbon: Metal ratio

Jonathon J. Host*, Mao H. Teng, Brian R. Elliott, Jin Ha Hwang, Thomas O. Mason, D. Lynn Johnson, Vinayak P. Dravid

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Graphite encapsulated nanocrystals produced by a low carbon tungsten arc were analyzed to determine their chemistry, crystallography, and nanostructural morphology. Metallic nanocrystals of Fe, Co, and Ni are in the face-centered cubic (fcc) phase, and no trace of the bulk equilibrium phases of body-centered cubic (Fe) and hexagonal close-packed (Co) were found. Various analytical techniques have revealed that the encased nanocrystals are pure metal (some carbide was found in the case of Fe), ferromagnetic, and generally spherical. The nanocrystals are protected by turbostratic graphite, regardless of the size of the nanocrystals. The turbostratic graphite coating is usually made up of between 2 and 10 layers. No trace of any unwanted elements (e.g., oxygen) was found. The low carbon : metal ratio arc technique is a relatively clean process for the production of graphite encapsulated nanocrystals.

Original languageEnglish (US)
Pages (from-to)1268-1273
Number of pages6
JournalJournal of Materials Research
Volume12
Issue number5
DOIs
StatePublished - May 1997

Funding

This work was supported by National Science Foundation, Grant DMR-9202574, and by the MRL Program of the National Science Foundation at the Materials Research Center of Northwestern University, under Award No. DMR-9120521. Vinayak P. Dravid was also partially supported by the National Science Foundation NYI program, Grant DMR-9357513, with matching support from the Exxon Education Foundation.

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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