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

Journal Article · · Chemistry of Materials
DOI:https://doi.org/10.1021/cm901708v· OSTI ID:1019733

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 Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
Sponsoring Organization:
DOE - OFFICE OF SCIENCE
DOE Contract Number:
DE-AC02-98CH10886
OSTI ID:
1019733
Report Number(s):
BNL-95579-2011-JA; CMATEX; TRN: US201115%%372
Journal Information:
Chemistry of Materials, Vol. 21, Issue 23; ISSN 0897-4756
Country of Publication:
United States
Language:
English