Abstract: The present invention relates to novel binder and slurry formulations used to form molds for casting metal alloys and, more particularly, reactive metal alloys. The shell molds lead to more uniform castings which exhibit limited alpha case as compared to other currently available shell mold systems.

Abstract: The present invention relates to novel binder and slurry formulations used to form molds for casting metal alloys and, more particularly, reactive metal alloys. The shell molds lead to more uniform castings which exhibit limited alpha case as compared to other currently available shell mold systems.

Abstract: The present invention relates to novel binder and slurry formulations used to form molds for casting metal alloys and, more particularly, reactive metal alloys. The shell molds lead to more uniform castings which exhibit limited alpha case as compared to other currently available shell mold systems.

Abstract: The present invention relates to novel binder and slurry formulations used to form molds for casting metal alloys and, more particularly, reactive metal alloys. The shell molds lead to more uniform castings which exhibit limited alpha case as compared to other currently available shell mold systems.

Abstract: Investment casting shells, methods for their manufacture and methods for casting metals and alloys using such shells are disclosed. One feature of the shells is that the facecoat plus interior backup layers are purposefully designed to have substantially similar coefficients of thermal expansion to the seal dip layers. This helps reduce the occurrence of dimensional casting defects caused by differential thermal expansions of the layers comprising the shell. One embodiment of such a shell comprises a facecoat, plural interior backup layers and plural intermediate backup layers wherein at least one of the plural intermediate backup layers comprises a material capable of undergoing a volumetric transformation during cool down, and wherein the seal-dip layers have a coefficient of thermal expansion that varies from the coefficient of thermal expansion of the facecoat and interior backup layers by less than about 10 percent.

Abstract: A method for dispersing and reducing the rate of dissolution and/or hydration of colloidal ceramic suspensions is described. The method comprises adding to a ceramic suspension a non-polymeric hydroxylated organic compound. The organic compound has at least one hydroxyl group, preferably at least two hydroxyl groups. The organic compound also includes a functional group selected from the group consisting of a carboxyl, a carboxylate, a sulfonic acid, a sulfonate, a phosphoric acid, a phosphate, an amine, and a quaternary ammonium salt. The ceramic suspension typically comprises a colloidal suspension of a metal oxide, wherein the metal of the metal oxide is an alkali metal, alkaline-earth metal or a rare-earth metal, but preferably is magnesium, calcium or a rare-earth metal. The non-polymeric organic compound is added to the suspension in an amount effective to substantially disperse and reduce the rate of dissolution of the ceramic particles, such as from about 0.01 weight percent to about 5.

Abstract: The disclosure describes an aqueous ceramic slurry having from about 70-weight percent to about 85 weight-percent of a fused yttria-zirconia material. The weight percent of zirconia in the fused yttria-zirconia preferably varies from about 1.0 weight percent to about 10.0 weight percent. Fused slurries may comprise, in addition to fused yttria-zirconia, an inorganic binder (preferably silica), an organic binder (preferably a latex binder), a surfactant (preferably a sodium dioctyl sulfosuccinate), an antifoaming agent (preferably a water-dilutable active silicone defoamer) and titanium dioxide. The slurries of the present invention are used to form ceramic mold facecoatings for casting reactive materials. These slurries are less sensitive to pH fluctuations than are slurries made from 100 percent yttria (yttria slurries). Moreover, slurries as described in the disclosure do not gel prematurely, and exhibit substantially the same formation of oxygen-enriched titanium (alpha case) than do yttria slurries.

Abstract: The disclosure describes an aqueous ceramic slurry having from about 70-weight percent to about 85 weight-percent of a fused yttria-zirconia material. The weight percent of zirconia in the fused yttria-zirconia preferably varies from about 1.0 weight percent to about 10.0 weight percent. Fused slurries may comprise, in addition to fused yttria-zirconia, an inorganic binder (preferably silica), an organic binder (preferably a latex binder), a surfactant (preferably a sodium dioctyl sulfosuccinate), an antifoaming agent (preferably a water-dilutable active silicone defoamer) and titanium dioxide. The slurries of the present invention are used to form ceramic mold facecoatings for casting reactive materials. These slurries are less sensitive to pH fluctuations than are slurries made from 100 percent yttria (yttria slurries). Moreover, slurries as described in the disclosure do not gel prematurely, and exhibit substantially the same formation of oxygen-enriched titanium (alpha case) than do yttria slurries.

Abstract: A method and process for producing a yttrium oxide metal casting refractory composition is disclosed. Powdered Y.sub.2 O.sub.3 is combined with a sintering agent (preferably V.sub.2 O.sub.5) and an organic binder. The mixture is sintered and ground to produce a stable Y.sub.2 O.sub.3 flour. The flour is added to another binder having specific SiO.sub.2, hydrolysis and viscosity levels in order to produce a slurry. Slurries prepared in accordance with the invention avoid problems traditionally associated with Y.sub.2 O.sub.3 hydration and/or carbonation, and have long storage lives. In addition, the material costs associated with the slurries are low in comparison with products using fused Y.sub.2 O.sub.3. The Y.sub.2 O.sub.3 slurries may also find application as solid preformed cores formed by any conventional injection molding, transfer molding, or slurry casting process.

Abstract: Y.sub.2 O.sub.3 is recovered from investment casting shell molds by introducing used mold materials into a dissolution reactor preferably consisting of a rotating vessel having an interior lining of acid and abrasion resistant material. An acid is combined with the materials in the reactor and agitated for a selected time period. Thereafter, the liquid remaining in the reactor is separated from the residual solids and removed. The liquid contains dissolved Y.sub.2 O.sub.3 which is precipitated, preferably using oxalic acid to produce yttrium oxalate [Y.sub.2 (C.sub.2 O.sub.4).sub.3.9H.sub.2 O]. The Y.sub.2 (C.sub.2 O.sub.4).sub.3.9H.sub.2 O is ultimately removed from the solution and calcined to produce high purity Y.sub.2 O.sub.3.

Abstract: A highly efficient method for recovering Y.sub.2 O.sub.3 from casting slurries and cores containing Y.sub.2 O.sub.3 in combination with a binder is disclosed. The slurry is first treated with a gelling agent which causes the slurry to gel. The gelled slurry is then ignited in order to remove residual organic compounds. After ignition, the product is crushed and pulverized to form a powder. Thereafter, the powder is calcined at a temperature sufficient to crystallize the silica binder in the powder. The calcined product is subsequently dissolved in a heated acid solution for a selected time period. The resulting solution contains dissolved Y.sub.2 O.sub.3 and undissolved binder residue, which is filtered and removed. The Y.sub.2 O.sub.3 in the solution is then diluted with deionized water, and precipitated, preferably using oxalic acid to produce yttrium oxalate. The yttrium oxalate is ultimately removed from the solution and calcined to produce high purity Y.sub.2 O.sub.3.

Abstract: A system for the casting of metal comprising a filter through which the metal passes during pouring into a mold cavity. The filter is formed by providing a multiplicity of substantially spherical refractory particles. A ceramic binder is employed for securing the particles in a bonded assembly, the binder substantially completely coating the particles. Openings are defined between the adjoining coated particles to permit the flow of molten metal through the filter. The binder is of a type having an affinity for dross and slag constituents in the molten metal whereby the constituents are removed during passage of the metal through the filter. The refractory particles are preferably bonded into an assembly by processing which includes coating the particles with the binder material, introducing the coated particles into a mold and drying and firing the coated particles in the mold to achieve the desired bonded relationship.

Abstract: This invention is addressed to cores for use in the casting of high melting point metals wherein the core is formed of a refractory material, a silicone resin and a catalyst in the form of an anhydride of an organic carboxylic acid.