Abstract: Core-shell particles containing crystalline iron oxide in the core and amorphous silicon dioxide in the shell and in which a) the shell contains from 5 to 40% by weight of silicon dioxide, b) the core contains b1) from 60 to 95% by weight of iron oxide and b2) from 0.5 to 5% by weight of at least one doping component selected from the group consisting of aluminum, calcium, copper, magnesium, silver, titanium, yttrium, zinc, tin and zirconium, c) where the % by weight indicated are based on the core-shell particles and the sum of a) and b) is at least 98% by weight of the core-shell particles, d) the core has lattice plane spacings of 0.20 nm, 0.25 nm and 0.29 nm, in each case+/?0.02 nm, determined by means of HR-TEM.

Abstract: Provided is a composite material which is in pellet form and which has particles with a core-shell structure, where the core of the particles has one or more magnetic materials, and the shell is made of silicon dioxide, and the pellet has one or more crosslinkable polyethylene and/or polyethylene-containing copolymers. Also provided is a process for crosslinking polyethylenes, by mixing the composite material, one or more free radical initiators, and at least one polyethylene, and heating the mixture inductively.

Abstract: Functionalized magnetic core-shell particles which are present predominantly in the form of isolated, essentially spherical individual particles, the core of which consists essentially of one or more magnetic iron oxides, the shell of which consists essentially of impervious, amorphous silicon dioxide, and the functionalization of which consists of amino or epoxy group units on the surface of the particles, and which additionally have a mean particle diameter d50 such that 2<d50<10 ?m, the particles have a content of iron oxide of 83 to 92% by weight, of silicon dioxide of 5 to 15% by weight, and of carbon of 0.5 to 3% by weight, the amino or epoxy group is part of the structural unit —OSi-alkyl-X where X is NH2 or epoxy and alkyl is C2-C8, and the concentration of the amino groups or of the epoxy groups is at least 30 ?mol/g of particles. The particles are used for immobilization of enzymes.

Abstract: Core-shell particles containing crystalline iron oxide in the core and amorphous silicon dioxide in the shell and in which a) the shell contains from 5 to 40% by weight of silicon dioxide, b) the core contains b1) from 60 to 95% by weight of iron oxide and b2) from 0.5 to 5% by weight of at least one doping component selected from the group consisting of aluminium, calcium, copper, magnesium, silver, titanium, yttrium, zinc, tin and zirconium, c) where the % by weight indicated are based on the core-shell particles and the sum of a) and b) is at least 98% by weight of the core-shell particles, d) the core has lattice plane spacings of 0.20 nm, 0.25 nm and 0.29 nm, in each case +/?0.02 nm, determined by means of HR-TEM.

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.

Abstract: Composite material comprising—one or more heat-activatable free-radical initiators selected from the group consisting of organic peroxides and/or initiators having labile carbon-carbon bonds and particles which have a core-shell structure and the core of which comprises one or more magnetic materials, while the shell comprises silicon dioxide.

Abstract: Iron-silicon oxide particles with a core-shell structure, which have a) a BET-surface area of 10 to 80 m2/g, b) a thickness of the shell of 2 to 30 nm and c) a content of iron oxide of 60 to 90% by weight, of silicon dioxide of 10 to 40% by weight, based in each case on the enveloped particles, where d) the proportion of iron, silicon and oxygen is at least 99% by weight, based on the enveloped particles, and where e) the core is crystalline and the iron oxides comprise haematite, magnetite and maghemite, f) the shell consists of amorphous silicon dioxide and g) at least one compound or a plurality of compounds consisting of the elements silicon, iron and oxygen is/are present between shell and core.

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.

Abstract: Composite material comprising—one or more heat-activatable free-radical initiators selected from the group consisting of organic peroxides and/or initiators having labile carbon-carbon bonds and particles which have a core-shell structure and the core of which comprises one or more magnetic materials, while the shell comprises silicon dioxide.

Abstract: Composite material which is in pellet form and which comprises particles with a core-shell structure, where the core of the particles comprises one or more magnetic materials, and the shell comprises silicon dioxide, and which comprises a polyethylene crosslinkable in the presence of a heat-activatable free-radical initiator and/or polyethylene-containing copolymers. Process for the crosslinking of polyethylenes, by mixing the composite material, one or more heat-activatable free-radical initiator(s) and at least one polyethylene, and heating the mixture inductively.

Abstract: Iron-silicon oxide particles with a core-shell structure, which have a) a BET-surface area of 10 to 80 m2/g, b) a thickness of the shell of 2 to 30 nm and c) a content of iron oxide of 60 to 90% by weight, of silicon dioxide of 10 to 40% by weight, based in each case on the enveloped particles, where d) the proportion of iron, silicon and oxygen is at least 99% by weight, based on the enveloped particles, and where e) the core is crystalline and the iron oxides comprise haematite, magnetite and maghemite, f) the shell consists of amorphous silicon dioxide and g) at least one compound or a plurality of compounds consisting of the elements silicon, iron and oxygen is/are present between shell and core.

Abstract: An artificial stone for flat structures having antistatic properties, which contains ionic liquids or solutions of metal salts in ionic liquids as antistatic component, its use and a process for producing it.