Abstract: Precursors, particularly of non-oxide ceramics, are prepared by special seeding, under carefully controlled conditions. Such procedures can lead to the preparation of unique powders, which may be useful, for example as abrasives, or further processed in special manner to prepare a variety of metal substances. Such procedures can permit final firing to sintered product.

Abstract: Finely-divided titanium diboride or zirconium diboride powders are formed by reacting gaseous boron trichloride with a material selected from the group consisting of titanium powder, zirconium powder, titanium dichloride powder, titanium trichloride powder, and gaseous titanium trichloride.

Abstract: A powder composition suitable for the pressureless thermal sintering of articles which may be used in aluminium electro-thermics contains titanium boride with boron and titanium hydride as densifying additives. During sintering these additives form titanium boride. As this is identical to the substance of the sintered article the additives therefore do not constitute impurities in the sintered article.

Abstract: Non-oxide powders such as carbides, nitrides, carbides/nitrides and borides are obtained by reducing an oxide powder in a reducing atmosphere, and after or concurrently with the reduction, treating the reduced powder in a carbonizing atmosphere, a nitrogenizing atmosphere, a carbonizing and nitrogenizing atmosphere, or a boronizing atmosphere. As the above oxide powder, there is used a brittle material obtained by rapid cooling of a melted oxide. The non-oxide powders obtained are utilized as a hard component of cemented carbides and cermet. These powders are fine particles having a particle size of 1.0 .mu.m or smaller and a high purity.

Abstract: A method for removing oxide contamination from titanium diboride powder involves the direct chemical treatment of TiB.sub.2 powders with a gaseous boron halide, such as BCl.sub.3, at temperatures in the range of 500.degree.-800.degree. C. The BCl.sub.3 reacts with the oxides to form volatile species which are removed by the BCl.sub.3 exit stream.

Abstract: A process for production of ZrB.sub.2 powder in a molten salt bath by reaction of ZrCl.sub.4 or ZrCl.sub.2 with a boron halide and Al or Mg. In a preferred embodiment the salt bath comprises ZrCl.sub.4, KCl and NaCl maintained at a temperature of about 540.degree. to 660.degree. C. and solid Al powder is reacted with ZrCl.sub.4 and BCl.sub.3. The ZrB.sub.2 powder produced in a particularly preferred embodiment has a median particle size of about 1.1 microns, is equiaxed, and has only a single phase.

Abstract: TiB.sub.2 -carbon composites are produced by mixing the raw materials comprised of carbon, TiB.sub.2, pitch, and other reactants, forming a shaped article, processing in a nitrogen atmosphere up to 2100.degree. C., and in a noble gas above 2100.degree. C.

Abstract: A cathode component for a Hall aluminum cell is economically produced from a mixture of a carbon source, preferably calcined petroleum coke, and optionally calcined acicular needle petroleum coke, calcined anthracite coal; a binder such as pitch including the various petroleum and coal tar pitches; titanium dioxide, TiO.sub.2 ; and boric acid, B.sub.2 O.sub.3 or boron carbide, B.sub.4 C; forming said mixture into shapes and heating to a TiB.sub.2 -forming temperature.

Abstract: Submicron titanium diboride powder and other hard, refractory metal boride powders, such as zirconium diboride and hafnium diboride powders, are prepared by vapor phase reaction of the corresponding metal halide, e.g., titanium halide, and boron source reactants in the presence of hydrogen in a reaction zone and in the substantial absence of oxygen, either combined or elemental. In a preferred embodiment, the metal halide, e.g., titanium tetrachloride, and boron source, e.g., boron trichloride, reactants are mixed with a hot stream of hydrogen produced by heating hydrogen in a plasma heater. The reaction zone is maintained at metal boride forming temperatures and submicron solid metal boride powder is removed promptly from the reactor and permitted to cool. The preponderant number of metal boride particles comprising the powder product have a particle size in the range of between 0.05 and 0.7 microns.

Abstract: A method of removing boron impurity in a process for purifying silicon is disclosed wherein silicon is crystallized from a solvent metal. The method comprises the steps of providing a molten body containing silicon, the remainder aluminum and impurities and providing a metal selected from the group consisting of titanium, vanadium and zirconium therein, the metal from the group forming a reaction product with boron and permitting the reaction product to settle in the body for removal purposes.

Abstract: Submicron titanium diboride powder and other hard, refractory metal boride powders, such as zirconium diboride and hafnium diboride powders, are prepared by vapor phase reaction of the corresponding metal halide, e.g., titanium halide, and boron source reactants in the presence of hydrogen in a reaction zone and in the substantial absence of oxygen, either combined or elemental. In a preferred embodiment, the metal halide, e.g., titanium tetrachloride, and boron source, e.g., boron trichloride, reactants are mixed with a hot stream of hydrogen produced by heating hydrogen in a plasma heater. The reaction zone is maintained at metal boride forming temperatures and submicron solid metal boride powder is removed promptly from the reactor and permitted to cool. The preponderant number of metal boride particles comprising the powder product have a particle size in the range of between 0.05 and 0.7 microns.

Abstract: The preparation of refractory metal borides of Group 4b of the Periodic Table of the Elements by reaction in the vapor phase of the corresponding metal halide, e.g., metal chloride, with a boron source reactant in the presence of hydrogen in a reactor is described. Reactants are introduced into a reactant mixing zone containing hydrogen through reactant inlet assembly means. Refractory metal boride product deposits on the exposed surfaces of the reactant inlet assembly means are reduced significantly by introducing metal halide reactant and substantially anhydrous hydrogen halide into the hydrogen stream upstream of the boron source reactant while introducing boron source reactant mixed with inert carrier gas, e.g., argon, into said hydrogen stream downstream of the metal halide and hydrogen halide streams.

Abstract: A plasma-arc process is disclosed for the production of powders of various chemical products, according to endothermic reactions, such as TiC and the like. The process consists essentially in carrying out, in a furnace with an anodic function without dissipative cooling, a series of steps comprising:(a) forming a chemically reactive fluidodynamic mass having a high thermal content and a high concentration of the desired reactive species, by injecting into the electronic column of a plasma-arc of a noble gas at least one reactant selected from the class consisting of metal and metalloid halides, the injection taking place, with mixing through a choker-injector-mixer nozzle which is electrically insulated;(b) causing the electronic condensation of said mass inside a main nozzle anode without dissipative cooling; and(c) injecting into said electronically condensed mass the residual part of said reactants necessary to the desired main chemical reaction for producing the chemical powder.

Abstract: A bimetallic adhesive for surface bonding and for controlled release applications that is non-explosive and which also provides improved shock, moisture, temperature and spark resistance characteristics. The bimetallic adhesive comprises a resinous adhesive binder and a bimetallic mixture, which consists of boron and titanium powders. The bimetallic adhesive mixture provides a controlled release function to separate a bonded surface when heated to a temperature above 600.degree. C., thereby causing the mixture to react exothermically to effect complete deflagration of the mixture.

Abstract: A sintered compact of boron nitride with high density form having high oxidation resistance, water resistance, compressive strength and hardness can be obtained by sintering wurtzite-structured boron nitride together with a boride of titanium, zirconium or hafnium, or with mixtures thereof under a condition of high temperature and high pressure.

Abstract: Refractory metal diboride articles having an overall density of 50-90 percent of theoretical and a matrix of near theoretical density, e.g., 95-99 percent are described. They may be made by cold pressing and sintering an intimate mixture of submicron Group IVb metal diboride powder and finely divided solid hydrocarbon, e.g., microcrystalline petroleum wax. The hydrocarbon remains particulate in the cold pressed piece but is driven out by heat at the beginning of the sintering operation, thereby leaving voids which remain as gross pores surrounded by a dense matrix in the sintered article. Submicron boride powders capable of forming the dense matrix contain a minor proportion of a sintering or densifying aid such as carbon or a metal carbide such as titanium carbide, tungsten carbide, or boron carbide. The articles so produced are lighter in weight than non-porous articles of the same size, have high electrical conductivity and, by virtue of the dense matrix, have excellent resistance to chemical attack.

Abstract: Finely divided borides, carbides, and nitrides of metals of Groups III-VI of the Periodic Table, formed by reacting vaporous metal halide and a boron, carbon, or nitrogen source reactant at high temperatures, e.g., 1500.degree. C., are separated from gaseous reactor effluent stream at temperatures between about 200.degree. C. and 1500.degree. C. with the use of a porous sintered filter. By separating the finely divided product from the effluent stream before the stream cools to below about 200.degree. C., adsorption of impurities, e.g., unreacted metal halide or metal subhalides, on the product is reduced. The use of a filter, e.g., a porous sintered filter, avoids the size classification of product which may result when cyclones and a bag filter are used to collect product.

Abstract: Helical flow of hot plasma gas, e.g., hydrogen gas, produced by a gas vortex stabilized plasma arc is cancelled by introducing attenuating gas, e.g., hydrogen gas, into the hot plasma gas in a manner such that the attenuating gas assumes a vortical direction opposite to the helical flow of the hot plasma gas. The resulting gas stream is well-collimated. The well-collimated plasma gas stream is used in the preparation of finely-divided refractory metal and metalloid carbides, borides, nitrides, silicides and sulfides. Reactants for the preparation of the aforementioned refractory powders are introduced into the collimated plasma gas stream. The reaction is conducted in the gas phase within a reactor and solid, finely-divided refractory powder removed from the reactor.

Abstract: The preparation of metal and metalloid carbides, borides, nitrides silicides and sulfides by reaction in the vapor phase of the corresponding vaporous metal halide, e.g., metal chloride, with a source of carbon, boron, nitrogen, silicon or sulfur respectively in a reactor is described. Reactants can be introduced into the reactor through a reactant inlet nozzle assembly. Inhibition and often substantial elimination of product growth on exposed surfaces of such assembly is accomplished by introducing the corresponding substantially anhydrous hydrogen halide, e.g., hydrogen chloride, into the principal reactant mixing zone.

Abstract: Latex-based coating materials are prepared frequently by compounding the latex with large quantities of calcium carbonate fillers. Whenever these fillers contain water-soluble calcium and magnesium compounds as impurities latices prepared with anionic emulsifiers are made more unstable, apparently because of reaction between these impurities and the emulsifier. This instability can be overcome by including in the latex a water-soluble fluoride such as ammonium or potassium fluoride in an amount generally under 5 parts by weight per 100 parts dry weight of latex. The process involves adding such a fluoride in an amount sufficient to stabilize the latex, generally under 5 parts per hundred of latex, dry weight.