摘要:
Silicon-containing particles are used for protection of industrial materials, such as electrooptical layers or electrooptical components, from electromagnetic radiation in the UV range and optionally in the visible as far as the IR range, wherein the particles take the form of primary particles having a particle size in the range from 1 to 100 nm and may optionally take the form of clusters of the primary particles. A particular advantage is the possibility of matching the absorption of the electromagnetic radiation to the wavelength region to be absorbed that is of interest in a defined manner via the particle size and the particle size distribution. The silicon-containing particles can be used as biocompatible and biodegradable UV protection in industrial applications and compositions for industrial applications as formulations, such as preferably in coating compositions, such as paint.
摘要:
A method of fractionating a dispersion of oxidic nanoparticles wherein at least one step of the method is a membrane crossflow filtration step, the flow of the dispersion over the membrane being brought about by means of driven rotating parts; and dispersions of oxidic nanoparticles that are obtainable by the method.
摘要:
Surface-modified superparamagnetic oxidic particles, characterized by the following physicochemical characteristics: BET surface area 20 to 75 m2/g; Carbon content 0.5 to 6.0% by weight; Tamped density 150 to 500 g/l; Chlorine content 50 to 1000 ppm; Drying loss 0.1 to 4.0% by weight are prepared by contacting the oxides with the surface modifier either by spraying or vapour deposition and then heat-treating them. The surface-modified oxidic particles can be used as a filler in adhesives. Further fields of application are use for data carriers, as a contrast agent in imaging processes, for biochemical separation and analysis processes, for medical applications, as an abrasive, as a catalyst or as a catalyst support, as a thickener, for thermal insulation, as a dispersing assistant, as a flow assistant and in ferrofluids.
摘要:
A dispersion comprising particles of cerium oxide and sheet silicate and one or more aminocarboxylic acids and/or salts thereof, where the zeta potential of sheet silicate particles is negative and that of the cerium oxide particles is positive or equal to zero, and the zeta potential of the dispersion is negative overall, the mean diameter of the•cerium oxide particles is not more than 200 nm•sheet silicate particles is less than 100 nm, the content, based in each case on the total amount of the dispersion, of•cerium oxide particles is from 0.1 to 5% by weight•sheet silicate particles is from 0.01 to 10% by weight and•aminocarboxylic acid or salt thereof is from 0.01 to 5% by weight and the pH of the dispersion is from 7.5 to 10.5.
摘要:
A dispersion comprising cerium oxide particles and colloidal silicon dioxide particles, where—the zeta potential of the silicon dioxide particles is negative and that of the cerium oxide particles is positive or equal to zero, and the zeta potential of the dispersion is negative overall, and—the mean particle diameter of the cerium oxide particles is not more than 200 nm and that of the silicon dioxide particles is not more than 100 nm, the mean particle diameter of the cerium oxide particles being greater than that of the silicon dioxide particles—the cerium oxide/silicon dioxide weight ratio is from 1.1:1 to 100:1 and—the pH of the dispersion is from 7.5 to 10.5.
摘要:
Process for the production of a metal oxide powder having a BET surface area of at least 20 m2/g by reacting an aerosol with oxygen in a reaction space at a reaction temperature of more than 700° C. and then separating the resulting powder from gaseous substances in the reaction space, wherein the aerosol is obtained by atomisation using a multi-component nozzle of at least one starting material, as such in liquid form or in solution, and at least one atomising gas, the volume-related mean drop diameter D30 of the aerosol is from 30 to 100 μm and the number of aerosol drops larger than 100 μm is up to 10%, based on the total number of drops, and metal oxide powder obtainable by this process.
摘要:
A method of fractionating a dispersion of oxidic nanoparticles wherein at least one step of the method is a membrane crossflow filtration step, the flow of the dispersion over the membrane being brought about by means of driven rotating parts; and dispersions of oxidic nanoparticles that are obtainable by the method.
摘要:
Process for the production of a metal oxide powder having a BET surface area of at least 20 m2/g by reacting an aerosol with oxygen in a reaction space at a reaction temperature of more than 700° C. and then separating the resulting powder from gaseous substances in the reaction space, wherein the aerosol is obtained by atomisation using a multi-component nozzle of at least one starting material, as such in liquid form or in solution, and at least one atomising gas, the volume-related mean drop diameter D30 of the aerosol is from 30 to 100 μm and the number of aerosol drops larger than 100 μm is up to 10%, based on the total number of drops, and metal oxide powder obtainable by this process.
摘要:
A dispersion comprising particles of cerium oxide and sheet silicate, where—the zeta potential of the sheet silicate particles is negative and that of the cerium oxide particles is positive or equal to zero, and the zeta potential of the dispersion is negative overall, —the mean diameter of the cerium oxide particles is not more than 200 nm sheet silicate particles is less than 100 nm, —the proportion, based in each case on the total amount of the dispersion, of cerium oxide particles is from 0.1 to 5% by weight sheet silicate particles is from 0.01 to 10% by weight and—the pH of the dispersion is from 3.5 to
摘要:
Composite particles useful for absorbing in the UV-A and UV-B regions contain a zinc oxide matrix and cerium oxide domains, wherein the domains are located in and on the matrix, wherein a fraction of zinc oxide is 80 to 98% by weight and a fraction of cerium oxide is 2 to 20% by weight, in each case based on the composite particles, and wherein a BET surface area of said composite particles is from 5 to 100 m2/g.