An economic process for producing high quality finely divided silicon dioxide from mixtures comprising economical silicon compounds without operational disturbances is characterized by using as an Si source mixture of at least two silicon compounds, at least one being carbon-containing and at least one being carbon-free, supplying a fuel gas and an oxygen-containing source, the molar C/Si ratio of this mixture being between 10/BET and 35/BET, and the molar H/Cl ratio of this mixture being between 0.45+(BET/600) and 0.95+(BET/600), with BET being the specific surface area of the pyrogenic silicon dioxide under production, introducing this mixture as the main flow into a reaction space and igniting and reacting it, and isolating the resulting solid.

The invention relates to a method for synthesizing ultrasmall silica nanoparticles, useful in particular for diagnostics and/or therapy. More specifically, a method for synthesizing silica nanoparticles, said method comprising the mixing of at least one silane which is negatively charged at physiological pH with at least one silane which is neutral at physiological pH, and/or at least one silane which is positively charged at physiological pH, wherein: the molar ratio A of neutral silane(s) to negatively charged silane(s) is defined as follows: 0A6, the molar ratio B of positively charged silane(s) to negatively charged silane(s) is defined as follows: 0B5, the molar ratio C of neutral and positively charged silanes to negatively charged silane(s) is defined as follows: 0<C8. The invention also relates to the obtained ultrasmall silica nanoparticles.

A Si-containing film forming composition comprising a catalyst and/or a polysilane and a NH free, C-free, and Si-rich perhydropolysilazane having a molecular weight ranging from approximately 332 dalton to approximately 100,000 dalton and comprising NH free repeating units having the formula [N(SiH3)x(SiH2-)y], wherein x=0, 1, or 2 and y=0, 1, or 2 with x+y=2; and x=0, 1 or 2 and y=1, 2, or 3 with x+y=3. Also disclosed are synthesis methods and applications for using the same.

The present disclosure provides a method for fabrication of a glass preform. The method includes production of soot particles in a combustion chamber using a precursor material. The heating of the precursor material produces the soot particles along with one or more impurities. In addition, the method includes agglomeration of the soot particles. Further, the method includes separation of the soot particles from the one or more impurities. Also, the separation of the soot particles is performed in a cyclone separator. Furthermore, the method includes collection of the soot particles. Also, the soot particles are compacted with facilitation of a preform compaction chamber. Also, the compacted preform is sintered with facilitation of a sintering furnace. The compaction of the soot particles followed by sintering results in formation of the glass preform.

The present disclosure provides a system for generating fumed silica particles for manufacturing of an optical fiber preform. The system includes a generator and a plurality of inlets connected with the generator. The generator includes a plurality of burners. The plurality of inlets include a first inlet, a second inlet, a third inlet and a fourth inlet. The first inlet provides passage for flow of a precursor material to the generator. The second inlet provides passage for flow of a first gas to the generator. The third inlet provides passage for flow of a second gas to the generator. The fourth inlet provides passage for flow of a carrier gas to the generator. The plurality of burners enables a chemical reaction between the precursor material, the first gas and the second gas that facilitates the generation of the fumed silica particles.

A method of forming nanoparticles having superhydrophobicity includes preparing a PDMS film including a structure having a predetermined shape on a surface thereof, and generating the nanoparticles having superhydrophobicity on the surface of the PDMS film by combusting the surface of the PDMS film using a diffusion flame. Transparent nanoparticles having superhydrophobicity and oleophobicity may be generated simply and easily on the surface of the PDMS film.

A process for the production of nanoparticles from a liquid mixture comprising at least one precursor and at least one solvent in a reactor with continuous through-flow comprises the steps of feeding at least one oxygen-containing gas inflow stream having a temperature into the at least one reactor, adding at least one fuel having a temperature to the oxygen-containing gas inflow stream, wherein the fuel and the oxygen-containing gas inflow stream form a homogeneous ignitable mixture having a temperature, wherein the temperature of the homogeneous ignitable mixture is above the autoignition temperature of the homogeneous ignitable mixture, introducing at least one precursor-solvent mixture into the homogeneous ignitable mixture; autoignition of the ignitable mixture of oxygen-containing gas and fuel after an ignition delay time to form a stabilized flame and reacting the precursor-solvent mixture in the stabilized flame to form nanoparticles from the metal salt precursor, removing the formed nanoparticles.

Disclosed is a black powder comprising silica particles that contain carbon. Each of the silica particles is single-layered. The content of carbon contained in the surfaces of the silica particles measured by an X-ray photoelectron spectroscopy is 1% by mass or less.

The present invention relates to a process for preparing a metal oxide,

comprising a) spraying a liquid raw material comprising at least one metal compound by mixing it with a gas to form an aerosol;
b) forming a gaseous reaction mixture from the aerosol obtained in step a) by complete evaporation thereof;
c) converting the gaseous reaction mixture obtained in step b) to metal oxide in the presence of oxygen.

One aspect relates to a process for the preparation of a quartz glass body including: i.) providing a silicon dioxide granulate, ii.) making a first glass melt out of the silicon dioxide granulate, iii.) making a glass product out of at least one part of the glass melt, iv.) reducing the size of the glass product to obtain a quartz glass grain, v.) making a further glass melt from the quartz glass grain and vi.) making a quartz glass body out of at least one part of the further glass melt. Furthermore, one aspect relates to a quartz glass body obtainable by this process. Furthermore, one aspect relates to a reactor, which is obtainable by further processing of the quartz glass body.