Patent · US Active

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

US8906983B2 · kind B2 · utility

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18Claims

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Assignee

EVONIK DEGUSSA GMBH · DE

Inventors

Stipan Katusic · Bad Soden, DE
Peter Kress · Alzenau, DE
Peter Albers · Hanau, DE
Harald Herzog · Karlstein, DE

Key dates

Filing date	Dec 7, 2011
Grant date	Dec 9, 2014
Priority date	—
Expiry date	Dec 22, 2031

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC04B2235/549
WIPO fieldMaterials, metallurgy
WIPO sectorChemistry

Abstract

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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.