摘要:
Ultrafine metal oxide and mixed metal oxide ceramic particles are prepared by flame spray pyrolysis of a ceramic precursor solution containing one or more gycolato polymetallooxanes dissolved in a volatile organic solvent. Recycle of the nanosized particles disposed in additional ceramic precursor solution leads to larger particles. The metal oxide and mixed metal oxide particles may be converted to the respective nitrides by high temperature ammonolysis. The process produces high quality ceramic particles from inexpensive and relatively non-toxic reagents in high space-time yield.
摘要:
A process for the preparation of polymetallooxanes employing inexpensive metal sources such as sand, alumina, and rutile involves dissolving one or more group IIIa, IVa, IVb metaloxy compounds such as metal oxides, metal hydroxides, or hydrates thereof with a di- or polyhydroxyl functional compound in the presence of an amine or alkanolamine. The polymetallooxane products are anionic, neutral, or mixed neutral/anionic moieties, which, when anionic, contain a metallic counterion (cation) or an ammonium or phosphonium ion. Mixed polymetallooxanes, as well as homo polymetallooxanes which may be prepared by the subject process, are suitable for use in preparing coatings, fibers, powders, ceramics, and glasses while being easily processable and economic to manufacture.
摘要:
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).
摘要:
Inorganic/organic hybrid polymers containing silsesquioxane cages are robust and exhibit desirable physical properties such as strength, hardness, and optical transparency at infrared and ultraviolet wavelengths. The polymers are prepared by polymerizing functionalized polyhedral silsesquioxane monomers such as polyhedral silsesquioxanes bearing two complementarily reactive functional groups bonded to cage silicon atoms by means of spacer moieties. The spacer moieties allow for steric mobility and more complete cure than polyhedral silsesquioxanes bearing reactive functional groups bound directly to cage silicon atoms.
摘要:
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.
摘要:
A system for underfilling in a chip package includes an underfill mixture that ameliorates the CTE mismatch that typically exists between a packaged die and a resin-impregnated fiberglass mounting substrate. In one embodiment, the system includes an underfill mixture that comprises a principal underfill composition of a rigid octaaminophenyl silsesquioxane (OAPS) that is used as a curing agent for a tetrafunctional, low viscosity, and relatively rigid TGMX epoxy resin. An embodiment is also directed to the assembly of a flip chip package that uses the underfill mixture.
摘要:
Functionalized silsesquioxanes containing from 6 to 24 silicon atoms and minimally about 67 mol percent RSiO3/2 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.
摘要:
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.
摘要:
A process is provided for the preparation of metals, metal carbides, nitrides, borides, silicides, sulfides and phosphides by low temperature pyrolysis of a selected organometallic precursor. The precursor, in addition to containing organic ligands, contains the metal M, which is a transition metal or tin, and the element X (C, N, B, Si, S, or P), which may be bound directly to M, contained within the ligands, or both. The process enables one to provide surface coatings or shaped articles of metals, metal carbides, nitrides, and the like.
摘要:
Transition metal carbides in which the carbon is in excess and is covalently bound to the metal are produced by pyrolyzing transition metal amides that have two or more metal atomos, such as hexakis(dimethylamido) ditungsten or dimolybdenum.