The Synthesis of Silica-Coated Permalloy Nanoparticles Using a Water-in-Oil Microemulsion

摘要

A water-in-oil microemulsion method was used for the preparation of silica-coated permalloy (Ni_(0.80)Fe_(0.20)) nanoparticles. The particles were prepared by the reduction of their salts with sodium borohydride NaBH_4 in a cationic water-in-oil (w/o) microemulsion of water/cetyl-trimethyl-amonium bromide (CTAB) and n-butanol/isooctane at 25°C. According to the TEM and x-ray diffraction analyses, the synthesized material was in the form of nanoparticles. The magnetization of the silica-coated nanoparticles was lower than that of the uncoated particles, reflecting the influence of the nonmagnetic silica surface layer on the magnetization.