SiO_2-Coated Fe-Ni Alloy Core-Shell Structures Synthesized by A Facile Chemical Method

摘要

Fe-Ni@ SiO_2core-shell structured micrometer spherical particles with nanometer thick SiO_2 shell were fabricated by a facile wet chemical process, their compositions and mechanisms were investigated using x-ray diffraction and Fourier transform of infra-red spectra, and their microstructures and magnetic properties were analyzed by high-resolution transmission electron microscopy and vibrating sample magnetometer. The structure of the synthesized SiO_2-coated Fe-Ni alloy particles varied with adding TEOS contents. As-prepared Fe-Ni@SiO_2 composites exhibit typical soft magnetic properties. Their highest saturation magnetization approximately linear decreases from 176 emu g~(-1)for pure Fe-Ni alloy powders to 121 emu g~(-1)for the coated powders with 20nm amorphous silica layers, but the coercivity of all different thickness SiO_2-coated Fe-Ni alloy powders maintains in the range of about 25 Oe.