A novel sol–gel process to facilely synthesize Ni3Fe nanoalloy nanoparticles supported with carbon and silica

• Ultrafine Ni3Fe nanoalloy nanoparticles were synthesized via a modified novel sol–gel process.
• The prepared Ni3Fe nanoalloy nanoparticles have a narrow size distribution.
• The Ni3Fe nanoparticles exhibit superparamagnetic behaviors at room temperature.

In this paper, we present a modified novel silica sol–gel process and explored the possibility, for the first time, to synthesize binary nanoalloy nanoparticles. We successfully prepared ultrafine Ni3Fe nanoparticles supported with carbon and silica via this simple one-pot reaction without H2 reduction. X-ray diffraction (XRD) and selected area electron diffraction (SAED) investigations of the Ni3Fe nanoparticles show that the nanoparticles have a face-centered-cubic (fcc) crystal structure. The TEM images show that grain sizes of Ni3Fe nanoparticles have a narrow size distribution. Moreover, the grain size of the nanoparticles is not very sensitive to the elevated annealing temperature. The Ni3Fe nanoparticles exhibit typical superparamagnetic behavior at room temperature, and the blocking temperatures (TB) are determined by the temperature-dependent magnetization (M–T curves) measurements. This novel silica sol–gel method is expected to have broad applications in synthesizing nanoalloy nanoparticles.

The TEM and HRTEM images and the magnetization curves taken in both zero-field-cooled (ZFC) and field-cooled (FC) modes of Ni3Fe nanoparticles calcined at 300 °C for 2 h under Ar flowing.Figure optionsDownload as PowerPoint slide