Iron-silicon oxide particles having an improved heating rate in an alternating magnetic and electromagnetic field

摘要

Iron-silicon oxide particles with a core and an outer shell have improved heating rates in a magnetic field. The core contains maghemite, magnetite, and haematite. The outer shell is essentially or exclusively silicon dioxide. The crystallite diameter of the haematite determined by X-ray diffraction is greater than 120 nm. A ratio of the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.20+/−0.02 nm, comprising maghemite and magnetite, to the brightness of the Debye-Scherrer diffraction ring by electron diffraction at a lattice plane spacing of 0.25+/−0.02 nm, comprising maghemite, magnetite and haematite, is no more than 0.2.

主权项

1. An iron-silicon oxide particle, comprising:
a core and an outer shell, wherein the core comprises maghemite, magnetite, and haematite, as iron oxide modifications, the outer shell consists essentially or exclusively of amorphous silicon dioxide, the particle satisfies: B0.20 nm/B0.25 nm is ≦0.2, B0.20 nm is brightness of a Debye-Scherrer diffraction ring determined by electron diffraction at a lattice plane spacing of 0.20+/−0.02 nm, comprising maghemite and magnetite, B0.25 nm is brightness of a Debye-Scherrer diffraction ring determined by electron diffraction at a lattice plane spacing of 0.25+/−0.02 nm, comprising maghemite, magnetite and haematite, and a crystallite diameter of the haematite determined by X-ray diffraction is greater than 120 nm.