Abstract:
The present invention is directed to a method for providing an agricultural waste product having amorphous silica, carbon, and impurities; extracting from the agricultural waste product an amount of the impurities; changing the ratio of carbon to silica; and reducing the silica to a high purity silicon (e.g., to photovoltaic silicon).
Abstract:
Nano- and micron sized metal oxide and mixed metal oxide particles are injected into a high temperature region wherein the temperature is between about 400°C and less than 2000°C, and collected as particles or as coatings wherein a particulate nature is substantially maintained. The particles are altered in at least one of phase, morphology, composition, and particle size distribution, and may achieve further changes in these characteristics by coinjection of metal oxide precursor in liquid form.
Abstract:
Silazanes and related compounds are prepared by (a) providing a precursor containing at least one Si-N bond, cleaving an Si-N bond in the precursor in the presence of hydrogen or a hydrogen donor, and reacting the cleavage product with a second cleavage product or with a compound containing an Si-H bond, an N-H bond, or both, to produce an initial silazane product having at least one newly formed Si-N bond or (b) providing one or more reactants which contain an Si-H bond and an N-H bond, and causing reaction to occur between the two bonds in the presence of a transition metal catalyst to form an initial silazane product having newly formed Si-N bonds. Further products may result from additional reaction of either type. Novel compounds, including siloxazanes and high molecular weight polysilazanes, are provided. The compounds may be pyrolyzed to yield ceramic materials such as silicon nitride, silicon carbide and silicon oxynitride. In a preferred embodiment, substantially pure silicon nitride and articles prepared therefrom are provided. Fibers, coatings, binders, and the like may be prepared from the novel materials.
Abstract:
The present invention discloses glycoxy silanes as a source of silica and silica precipitated by advantageous chemical reactions preferably beginning with biogenic silica. Alkoxy C-O-S 1 are hydrolyzed in a controlled fashion to nucleate formation of nanoparticles of silica. The growth rate of the particles is controlled by various parameters such that particles of known sizes, size distributions, specific surface areas and pore sizes and size distributions are recovered.
Abstract:
Fluoride catalyzed rearrangement reactions of polymeric silsesquioxanes [RSiO1.5]n involve reacting at least one silsesquioxane material with a catalytic amount of an organic fluoride at a temperature ranging from about -50C to about 120C thereby forming a reaction mixture for a period ranging from 60 minutes to 48 hours. To the reaction mixture, a quenching agent is added to remove fluoride from the reaction mixture. A silsesquioxane cage compound can be isolated from the reaction mixture using a precipitation or other extraction process.
Abstract:
Methods of making and compositions of dense sintered ceramic nano- and micro-composite materials that are highly stable in a variety of conditions and exhibit superior toughness and strength. Liquid feed flame spray pyrolysis techniques form a plurality of nanoparticles (e.g., powder), each having a core region including a first metal oxide composition comprising Ce and/or Zr or other metals and a shell region including a second metal oxide composition comprising Al or other metals. In certain aspects, the core region comprises a partially stabilized tetragonal ZrO2 and the shell region comprises an a-Al2O3 phase. The average actual density of the ceramic after sintering is greater than 50% and up to or exceeding 90% of a theoretical density of the ceramic.
Abstract translation:在各种条件下高度稳定且具有优异的韧性和强度的致密烧结陶瓷纳米和微复合材料的制备方法和组成。 液体进料火焰喷雾热解技术形成多个纳米颗粒(例如,粉末),每个纳米颗粒具有包含包含Ce和/或Zr或其它金属的第一金属氧化物组合物的芯区域和包含第二金属氧化物组合物的壳区域,所述第二金属氧化物组合物包含Al或 其他金属。 在某些方面,核心区域包括部分稳定的四方晶ZrO 2,并且壳区域包含a-Al 2 O 3相。 烧结后陶瓷的平均实际密度大于陶瓷的理论密度的50%以上且高达90%以上。
Abstract:
The invention is generally related to process for generating one or more molecules having the formula Si x H y , where x and y are integers ≥1, such as silane, comprising the steps of: providing a silicon containing material, wherein the silicon containing material includes at least 20 weight percent silicon atoms based on the total weight of the silicon containing material; generating a plasma capable of vaporizing a silicon atom, sputtering a silicon atom, or both using a plasma generating device; and contacting the plasma to the silicon containing material in a chamber having an atmosphere that includes at least about 0.5 mole percent hydrogen atoms based on the total moles of atoms in the atmosphere; so that a molecule having the formula Si x H y; (e.g., silane) is generated. The process preferably includes a step of removing one or more impurities from the Si x H y (e.g., the silane) to form a clean Si x H y (e.g., silane). The process may also include a step of reacting the Si x H y (e.g., the silane) to produce a high purity silicon containing material such as electronic grade metallic silicon, photovoltaic grade metallic silicon, or both.
Abstract:
Methods of forming UV-absorbent transparent coatings and transparent substrates coated with the same allow for a relatively lower temperature cross-linkage reaction between a UV-absorbent compound and an epoxy-alkoxysilane. More specifically, UV-absorbent coatings on transparent substrates are formed by prepolymerizing a mixture consisting essentially of a benzophenone, an epoxy alkoxysilane and an organic catalyst at a temperature of between about 40°C to about 130°C and for a time sufficient such that between about 30% to about 70% of the epoxy alkoxysilane has been converted to a ring-opened oligomer or polymer. Such prepolymerized mixture may then be hydrolyzed and coated onto the surface of a transparent substrate, and thereafter cured at a temperature of less than about 200°C for a time sufficient to cross-link the hydrolyzed alkoxysilane with itself and the glass surface. Most preferably , the prepolymerized mixture is hydrolyzed prior to being coated onto the substrate in an acidic alcoholic solution. Preferred for use in the present invention as a UV-absorbent compound is tetrahydroxybenzophenone. The preferred epoxy alkoxysilane is 3-glycidoxypropyl trimethoxysilane. It is especially preferred that prepolymerization be effected in the presence of an organic catalyst, such as triethylamine (TEA).
Abstract:
The present invention is directed to a method for providing an agricultural waste product having amorphous silica, carbon, and impurities; extracting from the agricultural waste product an amount of the impurities; changing the ratio of carbon to silica; and reducing the silica to a high purity silicon (e.g., to photovoltaic silicon).
Abstract:
Functionalized silsesquioxanes containing from 6 to 24 silicon atoms and minimally about 67 mol percent RSiO 3/2 moieties where R is a phenyl group bearing a chemically reactive functional group are highly suitable for use as nanoparticles in producing highly ordered nanocomposites of many types, containing a high proportion of interphase. The nanocomposites have unusual physicochemical properties due to the use of uniform, highly functionalized nanoparticles.