Abstract: Recycle friendly aluminum alloys are described which are variants of AA 3000 and AA 5000 series alloys containing higher than usual amounts of silicon and iron. The alloys contain in percentages by weight, more than 0.6-2.0% silicon, 0.9-2.4% iron, wherein the ratio of the amount of iron to the amount of silicon is in the range of 1.2-1.8:1. Other components of the alloys may include 0-0.4% copper, 0-1.5% manganese, 0-5.0% magnesium, 0-0.5% zinc, 0-3.5% chromium, 0-0.1% titanium and the balance aluminum and incidental impurities.

Abstract: Recycle friendly aluminum alloys are described which are variants of AA 3000 and AA 5000 series alloys containing higher than usual amounts of silicon and iron. The alloys contain in percentages by weight, more than 0.6-2.0% silicon, 0.9-2.4% iron, wherein the ratio of the amount of iron to the amount of silicon is in the range of 1.2-1.8:1. Other components of the alloys may include 0-0.4% copper, 0-1.5% manganese, 0-5.0% magnesium, 0-0.5% zinc, 0-3.5% chromium, 0-0.1% titanium and the balance aluminum and incidental impurities.

Abstract: A nonabrasive, corrosion-resistant, hydrophilic coating on aluminum sheet such as fin stock, produced by applying to the sheet surface a coating material containing, in an aqueous vehicle, effective amounts of nitrilotrismethylenetriphosphonic acid, phosphoric acid, and borate material of the group consisting of zinc borate and sodium borate, and essentially free of silica, alumina and precursors thereof, and heating the surface to establish the coating thereon. The coating formulation may also contains up to about 1 wt. % of polyacrylic acid and a surfactant to aid in application.

Abstract: A nonabrasive, corrosion-resistant, hydrophilic coating on aluminum sheet such as fin stock, produced by applying to the sheet surface a coating material containing, in an aqueous vehicle, effective amounts of nitrilotrismethylenetriphosphonic acid, phosphoric acid, and borate material of the group consisting of zinc borate and sodium borate, and essentially free of silica, alumina and precursors thereof, and heating the surface to establish the coating thereon. The coating formulation may also contains up to about 1 wt. % of polyacrylic acid and a surfactant to aid in application.

Abstract: A process for coloring metal flakes by dispersing the flakes in an inorganic metal oxide sol to coat the flakes with the sol, dispersing the sol-coated flakes in a solution of an inorganic metal compound in a solvent, and thereafter heating the flakes for producing thereon a sol-gel coating that imparts to the flakes a visible color different from the color of the metal flakes when uncoated. The sol, the compound and the solvent are mutually selected to form the color-providing sol-gel coating on the metal flakes upon heating. Aluminum flake pigments are colored in this manner using an aqueous alkaline zirconia sol and a solution of cobalt nitrate in ethanol and/or water or a solution of iron nitrate in ethanol (followed, in the case of iron nitrate, by a treatment with ammonium hydroxide in ethanol). The steps of successively dispersing the flakes in the sol and solution may be repeated to intensify the produced color.

Abstract: A process for producing fibres composed of or coated with carbides or nitrides. The process involves forming a first reaction zone containing microfine particles of an oxide (or oxide precursor) of silicon or a suitable metal (e.g. boron) uniformly mixed with carbon (or a carbon precursor); forming a second reaction zone comprising a layer having a thickness of 1 cm or less of a porous mass having a density of 1 g/cc or less formed of short or continuous fibres made of or coated with carbon (or carbon precursor); heating the first reaction zone in a non-oxidizing atmosphere to generate a gaseous sub-oxide of the silicon or metal; simultaneously heating the second reaction zone so that the gaseous sub-oxide diffuses into it and reacts with the carbon to form carbide or nitride on the fibres; and separating the resulting fibres from any carbide or nitride whiskers that may have formed in the second rection zone. Short or continuous fibres (e.g.

Abstract: A process of producing nitrides of aluminum and titanium. The process involves producing a uniform dispersion of microfine particles of the corresponding metal oxide in an infusible polymer, carbonizing the resulting dispersion in a non-oxidizing atmosphere and heating the carbonized product in a nitrogen atmosphere at high temperature to cause the oxide to react with the carbon and nitrogen to form the nitride. Before carbonization, however, the dispersion is formed into shapes in which none of the oxide particles is more than about 2.5 mm (0.098 inch) from an external surface and the shapes are loosely packed in a reactor. The process can achieve a good conversion of the oxide to the nitride to yield a product of high purity and small particle size.

Abstract: A process for producing unagglomerated single crystals of aluminum nitride having a size of at least 10 microns suitable for the reinforcement of metal and ceramic matrix composite materials. The process involves reacting alumina (or a precursor) with carbon under an atmosphere of nitrogen (or a precursor such as ammonia or an amine) at a temperature in the range of 1800.degree.-1950.degree. C. in the presence of an alkaki metal oxide (or precursor such as a carbonate) as a crystal growth promoter or catalyst. The alkali metal oxide is present in an amount required for the formation of crystals of the required size, preferably in the range of 10-60 microns. Particularly desirable crystals are produced if electrostatic precipitator dust is used as a source of the alumina, if petroleum coke or calcined anthracite coal is used as a source of the carbon and if the reaction is carried out in the presence of a porosity enhancer for the reaction mass, especially short cellulose fibres.

Abstract: A method of producing platelets of refractory metal borides and the platelets so-produced. The method involves reacting an oxide of a refractory metal or a precursor thereof and B.sub.2 O.sub.3 or a precursor thereof with carbon or a carbon precursor in the presence of a small amount of an alkali metal oxide, such as sodium oxide or potassium oxide, or a precursor. The reaction should take place under an atmosphere of an inert (non-reactive) gas. The alkali metal oxide allows the reaction temperature to be brought below 1800.degree. C., which reduces impurities in the product, and affects the shape of the particulate boride product, resulting in the formation of platelets. The carbon used in the reaction is preferably derived from calcined anthracite coal or petroleum coke because such carbon sources permit the reaction to be carried out at lower temperatures. The platelets of the refractory metal borides so-produced can be used as reinforcements for ceramic or metal matrix composites or for other purposes.

Abstract: A process for producing silicon carbide platelets and the platelets so produced. The process comprises reacting particles of a non-graphitizable form of hard carbon containing 0.5-1.5% by weight of aluminum and at least 0.2% by weight of iron (preferably anthracite coal, most preferably Pennsylvania anthracite), with silica or a silica precursor at a temperature in the range of 1900.degree.-2100.degree. C. under an inert atmosphere. If the carbon contains 0.2-1.0% by weight of iron, 0.1-10% by weight of boron, relative to the weight of SiO.sub.2, is added (if not already present). The carbon is in the form of particles of less than 50.mu. and the silica or precursor is preferably in the form of particles of less than about 1 .mu.. The weight ratio of silica to carbon is greater than 1.67:1. The resulting platelets are substantially unagglomerated and preferably of a size of less than 50.mu. with an aspect ratio greater than 5. The platelets can be used as reinforcements for ceramic and metal matrix materials.

Abstract: Shaped refractory products, particularly in the form of hollow spheres, and a process for their formation. The process involves dispersing particles of silica or a metal oxide, e.g. Al.sub.2 O.sub.3, in an organic polymer, shaping the dispersion into a desired shape, heating the shaped dispersion in a non-oxidizing atmosphere to carbonize the polymer, and heating the carbonized product at high temperature in a non-oxidizing atmosphere containing nitrogen so that some of the oxide is converted to the corresponding nitride and the particles of unreacted oxide sinter together. The ratio of oxide to carbon should be high so that some but not all of the oxide is converted to the nitride and, preferably, only a relatively small amount should be converted. The resulting refractory material is strong and can be used for a variety of uses, e.g. catalyst supports, packing materials and insulating materials.

Abstract: Porous membranes made of sintered refractory metal oxides, e.g., silica aluimina, titania, zirconia, tungsten oxide, etc., and to a process for their formation. The membranes are formed by dispersing a powder of the metal oxide in an organic polymer. The relative amount of metal oxide to polymer is such that, after the polymer has been carbonized in a subsquent step, there is a stoichiometrical excess of the oxide to carbon. The solution is then shaped to form a desired thin membrane, and the polymer is then carbonized by heating it in a non-oxidizing atmosphere. The resulting oxide/carbon product is heated to a temperature at which (a) the carbon reacts with the oxide to form a volatile sub-oxide and carbon monoxide and (b) the remaining (unreacted) oxide particles sinter together. The heating is carried out in a non-oxidizing atmosphere containing either no nitrogen whatsoever, or an amount of nitrogen less than that which results in the formation of a non-porous product.

Abstract: A cement for collector bar-carbon block joints of electrolytic cells, particularly for cells used for the production of aluminum. The cement comprises an aggregate of calcined anthracite or an anthracite/graphite mixture, a settable liquid polymeric binder and a curing agent for causing the binder to set. The cement is formulated so that it has a linear shrinkage of about 0.3 to 1.5% when exposed to the operating temperatures of the cell. The cement maintains a good electrical connection between the collector bar and carbon block without causing cracking of the block or of the cement.

Abstract: A method of producing whiskers of silicon carbide and other materials. For the formation of silicon carbide, the method involves forming a first reaction zone containing microfine particles of silicon dioxide uniformly mixed with carbon or a carbon precursor, with the ratio of the silicon dioxide to the carbon present as a starting material or derivable from the precursor being greater than about 5 to 1 by weight. A closely adjacent second reaction zone is formed containing a porous fibrous mass of active carbon or an infusible carbon precursor. The reaction zones are heated under a non-oxidizing atmosphere to temperatures at which silicon monoxide is formed in the first reaction zone, diffuses to the second reaction zone and reacts with carbon derived from the carbon precursor in the second reaction zone to form silicon carbide whiskers.