The present disclosure relates to a combined treatment method for surface modification of fumed silica, which comprises the following steps: (1) two sets of modification devices are used to jointly treat fumed silica; the fumed silica is modified with a modifier in the reaction furnace of each set of modification devices to obtain two groups of modified fumed silica and exhaust gas respectively; (2) the exhaust gas obtained in step (1) is separated respectively to obtain unreacted modifier and by-products, and the obtained by-products are input into the reaction furnace of the other set of modification devices as reaction assistants to participate in the modification reaction; and the obtained unreacted modifiers are returned to the reaction furnace of the original modification device for repeated use.

A method of manufacturing synthetic quartz used for supporting and placing a wafer with a focus ring or edge ring ceramic member which is used during a semiconductor manufacturing process, and the present invention is directed to providing a method of manufacturing cylindrical synthetic quartz which is capable of improving a yield by minimizing temporal loss and quantitative loss and significantly increasing the rate of synthetic quartz production.

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: 0≤A≤6, —the molar ratio B of positively charged silane(s) to negatively charged silane(s) is defined as follows: 0≤B≤5, —the molar ratio C of neutral and positively charged silanes to negatively charged silane(s) is defined as follows: 0<C≤8. The invention also relates to the obtained ultrasmall silica nanoparticles.

A cristobalite includes: a d50 particle size selected within a range of from 1 μm to 15 μm; an L color coordinate of greater than 96; a color coordinate of less than 1; and a b color coordinate of 1 or less, in which the cristobalite is a powder. Also provided are compositions containing the cristobalite, coatings formed with compositions, and methods of preparing cristobalite.

An object of the present invention is to provide a nanobubble-containing inorganic oxide fine particle dispersion having excellent concentration stability in a process used as an abrasive. The object is achieved by the nanobubble-containing inorganic oxide fine particle dispersion including: inorganic oxide fine particles having an average particle size of 1 to 500 nm and containing fine particles containing Ce; and nanobubbles having an average cell size of 50 to 500 nm and being at least one non-oxidizing gas selected from a group consisting of N.sub.2 and H.sub.2.

A silicon material can include a silicon aggregate comprising a plurality of porous silicon nanoparticles welded together. The silicon aggregate can optionally have a polyhedral morphology. A method can include: receiving a plurality of porous silicon nanoparticles and cold welding the plurality of porous silicon nanoparticles into an aggregated silicon particle.

The present invention relates to an abrasive and a planarization method using the same, and more particularly, includes fumed silica. A BET specific surface area of the fumed silica is 200 m.sup.2/g to 450 m.sup.2/g, a shape of aggregates dispersed in the abrasive has an elongated shape or a round shape, and a ratio of the round shape of the aggregates is 50% to 90%.

The present invention relates to an abrasive and a planarization method using the same, and more particularly, includes fumed silica. A BET specific surface area of the fumed silica is 200 m.sup.2/g to 450 m.sup.2/g, a shape of aggregates dispersed in the abrasive has an elongated shape or a round shape, and a ratio of the round shape of the aggregates is 50% to 90%.

A method for producing hollow silica particles, comprising: (i) producing a first batch of core-shell particles in which each core-shell particle contains a sacrificial core coated with a silica shell, by adding a tetrahydrocarbyl orthosilicate and hydroxide base to a suspension of sacrificial core particles in a solvent-water mixture, wherein the resulting suspension has a pH of at least 10, and wherein the foregoing steps result in a coating of silica on the sacrificial core particles to produce the first batch of core-shell particles; (ii) separating the first batch of core-shell particles from the solvent-water mixture; (iii) producing a second batch of core-shell particles in the first-stage recovered solvent-water; (iv) separating the second batch of core-shell particles from the first-stage recovered solvent-water mixture; and (v) subjecting the dry first and second batches of core-shell particles to a core removal process to produce the hollow silica particles.

A method for producing hollow silica particles, comprising: (i) producing a first batch of core-shell particles in which each core-shell particle contains a sacrificial core coated with a silica shell, by adding a tetrahydrocarbyl orthosilicate and hydroxide base to a suspension of sacrificial core particles in a solvent-water mixture, wherein the resulting suspension has a pH of at least 10, and wherein the foregoing steps result in a coating of silica on the sacrificial core particles to produce the first batch of core-shell particles; (ii) separating the first batch of core-shell particles from the solvent-water mixture; (iii) producing a second batch of core-shell particles in the first-stage recovered solvent-water; (iv) separating the second batch of core-shell particles from the first-stage recovered solvent-water mixture; and (v) subjecting the dry first and second batches of core-shell particles to a core removal process to produce the hollow silica particles.