Abstract: A process for the preparation of preceramic metallopolysilanes is described. The process consists of reacting polysilanes with metallic compounds from which can be generated open coordination sites associated with the metallic element. Such open coordination sites can be generated by the reduction of the metallic compound with an alkali metal reducing agent, or by heating a metallic compound which has thermally labile ligands, or by the UV irradiation of a carbonyl-containing metallic compound. The metals which can be incorporated into the polysilane include aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium, and tantalum. These metallopolysilanes are useful, when fired at high temperatures, to form metal-containing ceramic materials.

Abstract: The present invention relates to a process for the production of ferrosilicon in a closed two-stage reduction furnace. In the present invention, carbon monoxide released as a result of the smelting process, in the first stage of the furnace, is used to prereduce higher oxides of iron, for example Fe.sub.2 O.sub.3 and Fe.sub.3 O.sub.4, contained in a second stage of a furnace, to iron monoxide (FeO). The iron monoxide is then used as a feed material to the first stage of the furnace. The use of a closed furnace and a pre-reduction process results in substantial energy savings in the production of ferrosilicon alloy.

Abstract: What is disclosed is a method of improving the performance of the direct process for preparing alkylhalosilanes using an alkylhalide and silicon. The method is based on the control of the phosphorous that enters the silicon used in the direct process, by controlling the amount of phosphorous that enters the silicon during the manufacture of the silicon itself.

Abstract: This invention relates to materials produced by diluting in a solvent a platinum or rhodium catalyzed preceramic mixture of a hydrogen silsesquioxane resin. The preceramic mixture solvent solution is applied to a substrate and ceramified by heating. One or more ceramic coatings containing silicon carbon, silicon nitrogen, or silicon carbon nitrogen can be applied over the ceramified SiO.sub.2 coating. A CVD or PECVD top coating can be applied for further protection. The invention is particularly useful for coating electronic devices.

Abstract: A silicon smelting furnace and a process for utilizing this furnace for the production of silicon is described. The process involves a process in which equilmolar proportions of silicon carbide and silicon dioxide are charged to the reaction zone of a silicon furnace. Above the furnace is placed a shaft containing particulate carbon in the amount of 2 moles of carbon per mole of silicon dioxide charged to the reaction zone. As energy is applied to the reaction zone, molten silicon, gaseous silicon monoxide, and gaseous carbon monoxide are formed, the gases passing through the shaft of carbon, converting the carbon to silicon carbide. The silicon carbide, so formed, is combined with an equimolar proportion of silicon dioxide, and the cycle is repeated. Aside from an initial charge of silicon carbide, the feeds to the smelting furnace are silicon dioxide and carbon, silicon carbide being formed concurrently in a bed of carbon separated from the furnace reaction zone during the smelting cycle.

Abstract: A method is described to prepare preceramic polysilanes which contain at least one weight percent vinyl. To ensure the survival of the vinyl groups in the polysilane the reaction and process conditions must be carefully controlled. The vinyl-containing polysilanes can be formed into fibers, cured either thermally or by UV irradiation, and then pyrolyzed to form ceramic fibers. Thermal curing and pyrolysis can be combined into a single process step.

Abstract: An improved process for the preparation of multi-organic substituted silanes from the reaction of halides of silicon with an alkyl halide in the presence of a halogen-accepting metal is described. The improvement integrates a redistribution process into the alkylation process. The redistribution process involves an interaction between a multi-organic substituted silane and a halosilane with fewer organic substituents whereby an organic group from the multi-organic substituted silane is exchanged with a halogen group of the less organic substituted halosilane.

Abstract: The preparation of highly densified ceramic bodies by sintering certain curable organopolysiloxanes filled with silicon carbide powders, metal-containing sintering aids, and organopolysiloxane curing agents described. Such highly densified ceramic bodies can be prepared by either a pressure-less or a hot press sintering process. The compositions of this invention can be formed into desired shapes and then sintered to form ceramic, shaped bodies with high densities. One advantage of the present invention is that the green bodies have relative high strengths and thus can be easily handled and, if desired, machined before sintering. The curable organopolysiloxanes useful in this invention must yield a ceramic char which contains free or excess carbon in addition to carbon in the form of silicon carbide upon pyrolysis to elevated temperatures.

Abstract: Polysilanes of the general formula (RSi).sub.n wherein R is an alkyl, aryl, alkaryl or aralkyl group having 4 to 18 carbon atoms and where n has a value of at least 8, are soluble in a liquid organic medium when R is a stearically hindered or large group. Compositions comprising the organic liquid medium and dissolved therein the polysilane are also described.

Abstract: Cyclic silethynyl polymers, having at least 4 silicon atoms per polymer, have the average formula ##STR1## Preferably x has a value of 5 or 6, and each R is independently methyl or phenyl. They are prepared by reacting a lithium salt of one or more diehtynylsilanes with one or more dihalosilanes. These polymers are useful for example in semi- or photoconductive applications.

Abstract: This invention deals with new and novel polysilazane polymers, a method for their preparation, and the ceramic materials prepared thereby. An example of such a material is one which is prepared by the reaction of HSiCl.sub.3 and {(CH.sub.3).sub.2 SiNH}.sub.x.

Abstract: What is disclosed is a process for the rearrangement of cylcoorganopolysilazanes to cycloorganotrisilazanes using quaternary ammonium halides as a catalyst. The quaternary ammonium halide has the formula R.sup.i.sub.4 NX where at least one R.sup.i is a group containing greater than 11 carbon atoms and X is a halogen atom. The rearrangement process is ran either as a batch or a continuous distillation procedure.

Abstract: Mixtures of hydrogen silsesquioxane resin and metal oxide precursors such as acyloxy and alkoxy compounds of aluminum, zirconium, and titanium can be coated on substrates and subsequently ceramified at low temperature in the presence of ammonia, with or without platinum or rhodium catalysis, to form a nitrided ceramic coating on the surface of the substrate. The nitrided coatings produced are useful as interlevel dielectric films or for planarizing and protecting the surface of electronic devices. For further surface protection, overcoating the nitrided coating with an additional layer of a passivating ceramic material and a top layer of a barrier ceramic material is also described.

Abstract: A method is disclosed for the preparation of ceramic materials or articles by the pyrolysis of preceramic polymers wherein the preceramic polymers are rendered infusible prior to pyrolysis by exposure to gaseous nitric oxide. Ceramic materials with low oxygen content, excellent physical properties, and good thermal stability can be obtained by the practice of this invention. This method is especially suited for the preparation of ceramic fibers.

Abstract: Hydrogen silsesquioxane resin can be ceramified at low temperature in the presence of ammonia, with or without platinum or rhodium catalysis, to form a ceramic coating on the surface of a substrate. The nitrified silica coatings produced are useful as interlevel dielectric films or for planarizing and protecting the surface of electronic devices. For further surface protection, overcoating the nitrided silica with an additional layer of a passivating ceramic material and a top layer of a barrier ceramic material is also described.

Abstract: Polysilanes having higher molecular weight are prepared in a higher yield by reacting diorganodihalosilanes with an alkali metal at a temperature of at least 150.degree. C. in a medium which comprises a solvent in which the diorganodihalosilane is soluble. Preferred solvents comprise siloxanes, particularly cyclic dimethylsiloxanes.

Abstract: Hydrolyzed or partially hydrolyzed mixtures of silicate esters and metal oxide precursors, are pyrolyzed at relatively low temperature in the presence of ammonia to form ceramic coatings on substrates such as electronic devices. The metal oxide precursors are soluble compounds, for example alkoxides, of aluminum, titanium, or zirconium. The coatings produced are useful for the protection of electronic devices. One or more coatings containing amorphous silicon, silicon carbon, silicon nitrogen, or silicon carbon nitrogen can be applied over the nitrided ceramic SiO.sub.2 /metal oxide coating for still further protection of electronic devices.

Abstract: The reaction of 1,1-dichlorosilacyclobutanes with nitrogen-containing difunctional nucleophiles gives polysilacyclobutasilazanes which can be crosslinked and also converted to ceramic materials.

Abstract: A method is disclosed for the preparation of ceramic materials or articles by the pyrolysis of vinyl- or allyl-containing preceramic silazane polymers wherein the vinyl- or allyl-containing preceramic silazane polymers are rendered infusible prior to pyrolysis by high energy radiation such as gamma rays or an electron beam. Preceramic polymer compositions containing a vinyl- or allyl-containing silazane polymers and mercapto compounds containing at least two mercapto groups may also be rendered infusible by such high energy radiation. This method is especially suited for the preparation of ceramic fibers.

Abstract: A method of forming at low temperatures silicon- and nitrogen-containing ceramic or ceramic-like coatings for the protection of electronic devices. The coatings are produced by the ceramification at temperatures of, or below, 400 degrees Centigrade of preceramic silicon nitrogen-containing polymer coatings deposited from a solvent solution. The coatings are useful for planarizing the surfaces of electronic devices and for passivation.