Gold-Coated Cementite Nanoparticles: An Oxidation-Resistant Alternative to -Iron

Journal Article · Thu Jan 01 04:00:00 EST 2009 · Chemistry of Materials

DOI:https://doi.org/10.1021/cm901708v· OSTI ID:1019733

Shultz, M; Calvin, S; Gonzalez-Jimenez, F; Mujica, V; Alleluia, B; Carpenter, E

Iron-based nanoparticles are desirable for many applications because of their magnetic properties and inherent biocompatibility. Metallic iron, or {alpha}-Fe, is the most sought after because of its high saturation magnetization (up to 220 emu/g). This magnetization in iron nanoparticles is difficult to reach or maintain because of the ease of oxidation, which greatly reduces the magnetization values (90 emu/g or less). Here, we report the synthesis of an iron-based nanoparticle comprising a magnetic cementite core (Fe{sub 3}C) that is more oxidation-resistant than {alpha}-Fe, an oxide layer, and a gold coating for passivation and easy functionalization. The nanoparticle structure was confirmed via X-ray absorption fine structure and Moessbauer experiments, and morphology was confirmed using transmission electron microscopy. Magnetic characterization yielded a saturation magnetization of 110 emu/g, thus demonstrating cementite as more stable alternative to {alpha}-Fe with higher magnetic moments than the iron oxides.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1019733
• Report Number(s): BNL--95579-2011-JA
• Journal Information: Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 23 Vol. 21; ISSN CMATEX; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION
CEMENTITE
COATINGS
FINE STRUCTURE
GOLD
IRON
IRON OXIDES
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MAGNETIZATION
MORPHOLOGY
OXIDATION
OXIDES
PASSIVATION
SATURATION
SYNTHESIS
TRANSMISSION ELECTRON MICROSCOPY
national synchrotron light source