Abstract: To form, on a ceramic member or a metal member, a thermal spray ceramic coating film which achieves both the quality of a ceramic coating film and gas barrier property, and with which a composite oxide having a melting point lower than the ambient temperature will not form when used as a coating film on a ceramic member or a metal member constituting a glass article manufacturing apparatus. A ceramic coating film-provided member comprising a ceramic member or a metal member and a thermal spray ceramic coating film formed on at least a part of the surface of the ceramic member or the metal member, wherein the thermal spray ceramic coating film contains Al2O3 and 12CaO.7Al2O3, and the weight ratio of CaO to Al2O3 (CaO/Al2O3) is more than 0.11 to 0.50.

Abstract: A system and method for moulding metal parts having a first metal structure (4) which is integrally attached to a rotating machine, where said structure (4) is associated with a cover (3) and a plurality of fastening elements (1, 2), and where, in turn, the structure (4) is integrally attached to a cylindrical metal die (5) containing a ceramic mould (7) and hardened sand (6) for filling the die (5).

Abstract: A shell mold is described. The shell mold includes a facecoat, a sealcoat, and a support disposed in between the facecoat and the sealcoat. The support includes a stucco in a concentration greater than about 40 volume percent of the support. The stucco includes a material that has a thermal conductivity greater than about 285 W/m-K.

Abstract: The process for investment casting of complex shapes has historically had 6 basic steps in it. Depending upon the path taken, these discrete steps have been reduced to either 5 steps, or to 2 steps, discarding the unwanted steps. Instead of having to generate the shape of each sacrificial pattern, the process generates either (A) a male tree containing a plurality of sacrificial patterns, already on their runners, onto which a mold shell can be formed, or, (B) a female shell, made of a refractory material, and forming internally the outside surfaces of the plurality of patterns and runners. This process removes both capital expenditure for tooling and process time by up to 90%. By removing several lengthy, time-dependant steps from the process the part cost and lead time are reduced.

Abstract: A casting process for producing metal alloy castings, facecoats and apparatuses suitable for carrying out the process, and castings produced by the process. The casting process entails the use of a mold having a cavity with a continuous aluminum-containing solid facecoat on its surface. A molten quantity of a metal alloy is introduced into the mold cavity so that the molten alloy contacts the solid facecoat. The mold is then allowed to cool to solidify the molten alloy and form a cast product. During the casting process, aluminum in the solid facecoat diffuses into the cast product to form an aluminum-containing surface region at the casting surface. Following removal of the cast product from the mold, an alumina-containing scale grows on the casting surface as a result of oxidation of the casting surface region.

Abstract: A method of manufacture of a wax model of an annular bladed turbomachine stator assembly includes in succession the positioning, in a mold, of a core intended to form the impression of a cavity of a blade of the assembly, the injection of a wax in the mold, and the removal of the wax model fitted with the core from the mold. The core is manufactured in metal and is positioned such that its radially internal end is housed in the portion of the mold defining the blade including the cavity, away from the radially internal end of this portion of the mold.

Abstract: The invention relates to a method and to a device for sing out this method, during which the shell molds (3) are filled with a melt (11) in a clocked manner, the respectively required amount of melt being currently provided at the same time. The casting process ensues by marrying the crucible (6), which is filled with a melt (11), with a shell mold (3) so that the crucible (6) and shell mold (3) form a common cavity (10), and this arrangement is subsequently tilted 180°, so that the melt (11) falls into the shell mold (3).

Abstract: A method for forming an article is described. The method includes the step of applying a precursor material to at least one surface of a mold structure for casting the article, and curing the applied precursor material. The precursor material includes facecoat-forming constituents which can be curably converted into a facecoat; and a protective coating-former for the article being cast. Molten material is then introduced into the mold structure, so as to come in contact with the facecoat formed from the cured precursor material. The molten material is cooled, to form the article. The cured precursor material, which is in contact with a surface of the cast article, is then reacted with the article, to form the protective coating on the surface of the article. Related mold structures are also described.

Abstract: A shell mold for casting molten material to form an article is described. The mold includes a shell for containing the molten material, formed from at least one of yttrium silicates, zirconium silicates, hafnium silicates, and rare earth silicates. The mold also includes a facecoat disposed on an inner surface of the shell that contacts the molten material. The facecoat can be made from the materials described above. A method of casting a niobium-silicide article is also described, using the shell mold described herein. A method of making the ceramic shell mold is described as well, along with a slurry composition used in the manufacture of the shell mold.

Abstract: Method and apparatus for prolonging the stability (working life) of a ceramic slurry and other aqueous mixture or dispersion containing a liquid silica-bearing or other component as well as the raw liquid silica-bearing component in ambient air over time by providing a gas blanket that reduces exposure to ambient air.

Abstract: A composition and method for forming investment casting shells includes using colloidal silica, zircon flour, and fused silica in a slurry which is applied to a pattern. After the slurry is applied to the pattern, it is allowed to partially or completely solidify. After the shell has solidified, the pattern may be melted or otherwise removed. A molten material is introduced into the shell and allowed to cool to form an article. Finally, the shell is broken away or otherwise removed from the article. The improved shell slurry composition and corresponding method minimizes pattern-to-pour cycle times and is environmentally friendly.

Abstract: Embodiments of a method for increasing the lifetime of a casting slurry are described. One feature of the disclosed embodiments comprises processing refractory materials that are used to form casting slurries to provide a substantial increase in slurry lifetime for slurries made using such processed materials compared to slurries made using materials not processed as described herein. One embodiment of the method comprises heat processing at least one refractory powder. Without limiting the invention to a theory of operation, processing is continued for a period of time sufficient to reduce the amount of hydration from a first hydration level to a second hydration level. A slurry is formed using the refractory powder at a hydration level which provides an increased slurry lifetime relative to the same material without processing according to the disclosed embodiments.

Abstract: A ceramic mould slurry is disclosed for forming moulds and metal castings of improved surface quality. The slurry comprises a binder, a gelling agent, a first refractory material having a density of &rgr;1 and a mean particle size of &agr;1, and a second refractory material having a density of &rgr;2 and a mean particle size of &agr;2, wherein &rgr;1>&rgr;2 and &agr;1<&agr;2. The denser refractory material migrates downward through the slurry toward the upward-facing mould surface, thereby allowing formation of a smooth and accurate surface.

Abstract: A method for imaging inclusions in metal or metal alloy castings is described. One embodiment of the present method first involves casting a metal or metal alloy article using an investment casting mold where the mold facecoat, and perhaps one or more of the mold backup layers, comprises an imaging agent distributed substantially uniformly throughout in amounts sufficient for imaging inclusions. The facecoat preferably comprises an intimate mixture of a refractory material and the imaging agent. Intimate mixtures can be produced in a number of ways, but a currently preferred method is to cocalcine the refractory material, such as yttria, with the imaging agent, such as gadolinia. The facecoat also can comprise plural mold-forming materials and/or plural imaging agents. The difference between the linear attenuation coefficient of the article and the linear attenuation coefficient of the imaging agent should be sufficient to allow imaging of the inclusion throughout the article.

Abstract: A method for imaging inclusions in metal or metal alloy castings is described. One embodiment of the present method first involves casting a metal or metal alloy article using an investment casting mold where the mold facecoat, and perhaps one or more of the mold backup layers, comprises an imaging agent distributed substantially uniformly throughout in amounts sufficient for imaging inclusions. The facecoat preferably comprises an intimate mixture of a refractory material and the imaging agent. Intimate mixtures can be produced in a number of ways, but a currently preferred method is to cocalcine the refractory material, such as yttria, with the imaging agent, such as gadolinia. The facecoat also can comprise plural mold-forming materials and/or plural imaging agents. The difference between the linear attenuation coefficient of the article and the linear attenuation coefficient of the imaging agent should be sufficient to allow imaging of the inclusion throughout the article.

Abstract: The molding sand comprises hollow microspheres of aluminum silicate, preferably with an aluminum content between 15 and 45% by weight, a wall thickness between 3 and 10% of the particle diameter and a particle size between 10 and 350 &mgr;m. These sands are useful to manufacture low density cores with good “veining” and penetration characteristics, moreover maintaining the mechanical properties of the core obtained. These cores are useful in the manufacture of iron casting.

Abstract: A ceramic casting shell mold having a pre-selected shape comprises alternate, repeating layers of a ceramic coating material and a ceramic stucco, defining a total thickness of the shell mold; and a ceramic-based reinforcing sheet disposed in the alternate, repeating layers of coating material and stucco at an intermediate thickness. The ceramic-based reinforcing sheet comprises a one-piece monolithic, integral body, which comprises a pattern of holes that enhance bonding between the ceramic-based reinforcing sheet and adjacent ones of the alternate, repeating layers of ceramic coating material. The ceramic-based reinforcing sheet conforms to the shape of the mold and providing structural reinforcement to the mold.

Abstract: The present invention relates to improvements in and relating to investment casting. In particular, the invention provides a method of investment casting, comprising the steps of mixing a binder, a refractory material, and a quantity of water-insoluble organic fibers to form a slurry; coating an expendable pattern with a coat of said slurry; and drying said coat or allowing said coat to dry to form a shell. The present invention further provides a refractory slurry for use in the method of the invention, and a kit of ingredients for putting the method of the invention into effect.

Abstract: Methods for increasing the lifetime of a casting slurry are described. One feature of the invention is processing refractory powders at a first hydration level to produce powders having a second, lower hydration level before the processed materials are used to form casting slurries. Processing according to the disclosed methods results in a substantial increase in the lifetime of a slurry made using such processed materials compared to slurries made using materials not processed as described herein. One embodiment of the method comprises heat processing at least one refractory powder, typically refractory powders which have undergone hydration subsequent to commercial production, for a period of time sufficient to reduce the amount of hydration from a first hydration level to a second hydration level. A slurry is formed using the refractory powder at an hydration level which provides an increased slurry lifetime relative to the same material without processing according to the method of the present invention.

Abstract: A ceramic investment shell mold is reinforced with a carbon based fibrous reinforcement having an extremely high tensile strength that increases as the mold temperature is increased especially within the range of casting temperatures employed for casting large directionally solidified industrial gas turbine components. The carbon based fibrous reinforcement is wrapped or otherwise positioned around the repeating ceramic slurry/stucco layers forming the intermediate thickness of the shell mold wall. The reinforced shell mold can be used to cast large directionally solidified industrial gas turbine components with accurate dimensional control.

Abstract: A disposable plunger for use in a pressing furnace for the fabrication of dental restorations. The plunger is fabricated of a refractory investment material such as gypsum-bonded, phosphate-bonded or ethyl silicate-bonded investment materials. The plunger is fabricated by known casting methods. The mold used for making the plunger can be supplied by a manufacturer of molds or can be easily made by using an alumina or similar plunger as a model. Laborious cleaning and grinding are not required with plungers herein described. Cracking problems that occur with prior art plungers are decreased, if not completely eliminated.

Abstract: Method of making a casting by investment casting of a metal or alloy, especially titanium and its alloys, in a ceramic investment shell mold in a manner to provide enhanced x-ray detectability of any sub-surface ceramic inclusions that may be present below exterior surfaces of the casting. The method involves forming a ceramic mold facecoat and/or back-up layer including erbia or other x-ray or neutron-ray detectable ceramic component. The facecoat/back-up layer is/are formed using a ceramic slurry comprising erbia and other optional ceramic particulates, an inorganic binder, and an inorganic pH control agent. The slurry is applied to a pattern of component to be cast to form the mold. A metal or alloy is cast in the mold, and the solidified casting is removed from the mold. The casting is subjected to radiography to detect any sub-surface ceramic inclusions below the exterior surface thereof not detectable by visual inspection of the casting.

Abstract: A technique for smoothing and otherwise changing the surfaces of porous bodies, such as ceramic molds, made using layer manufacturing processes, such as three dimensional printing processes. The surface finish of the mold can be smoothed by casting a slip of fine particles onto the surface to form a generally level, and preferably non-conformal, coating on the surfaces. In general, the fine particles of the slip are caused to be filtered out from the liquid, so that the fine particles come to rest at or near the surface of the body formed. They are typically, preferentially drawn toward concave regions of the surface, as compared to convex regions, thereby forming a non-conformal coating. Furthermore, other surface properties can be changed by tailoring the slip to produce those properties. The coating can be applied to external surfaces, and internal surfaces, such as would become the surface against which a molded part would be formed.

Abstract: A metal or metal alloy article is cast using an investment casting mold where the mold facecoat, and perhaps one or more of the mold backup layers, comprises an imaging agent distributed substantially uniformly throughout in amounts sufficient for imaging inclusions. The facecoat preferably comprises an intimate mixture of a refractory material and the imaging agent. Intimate mixtures can be produced in a number of ways, but a currently preferred method is to cocalcine the refractory material, such as yttria, with the imaging agent, such as gadolinia. The facecoat also can comprise plural mold-forming materials and/or plural imaging agents. The difference between the linear attenuation coefficient of the article and the linear attenuation coefficient of the imaging agent should be sufficient to allow imaging of the inclusion throughout the article. The metal or metal alloy article is then analyzed for inclusions by N-ray analysis.

Abstract: A non-metallic end effector for use in an endoscopic surgical tool includes a metallic core for strength and for providing a selected electrode surface on the end effector. Selectively conductive end effectors are manufactured by insert molding a plastic or ceramic or other non-conductive body around a metallic or otherwise conductive core. The conductive core is exposed on a selected portion of the working surface of the end effector and extends through the non-conductive body of the end effector for coupling to an electrical source. Selectively conductive end effectors of this type can also be manufactured by coating a cast end effector member with a non-conductive polymer or by metallically plating a non-conductive ceramic end effector member. By extending the conductive core of a selectively conductive end effector member to the pivot hole of the member, electrical coupling can be made through the clevis and tube of an endoscopic instrument.

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 mould is provided having a surface which defines a mould cavity, and the mould surface includes on at a least part thereof a compound comprising a nucleation agent. The mould is heated. A metal heated to a temperature 0-15.degree. C. above the liquidus temperature is poured into the heated mould cavity and the molten metal is solidified in the mould cavity.

Abstract: Method of making a casting by investment casting of a metal or alloy, especially titanium and its alloys, in a ceramic investment shell mold in a manner to provide enhanced x-ray detectability of any sub-surface ceramic inclusions that may be present below exterior surfaces of the casting. The method involves forming a ceramic mold facecoat and/or back-up layer including erbia or other x-ray or neutron-ray detectable ceramic component. The facecoat/back-up layer is/are formed using a ceramic slurry comprising erbia and other optional ceramic particulates, an inorganic binder, and an inorganic pH control agent. The slurry is applied to a pattern of component to be cast to form the mold. A metal or alloy is cast in the mold, and the solidified casting is removed from the mold. The casting is subjected to radiography to detect any sub-surface ceramic inclusions below the exterior surface thereof not detectable by visual inspection of the casting.

Abstract: A calcia mold facecoat is applied to a mold for casting parts composed of reactive metals such as titanium and titanium aluminide. The facecoat is composed of a calcium carbonate based slurry comprising a dense grain calcium carbonate powder and an aqueous based binder. It is applied to a wax or plastic pattern used in the lost wax process for fabricating a casting shell. The mold is built using multiple dipping of alumina-silicate slurries, and then fired at high temperatures in an oxygen rich environment. The metal part is cast before the fired mold can cool below about 800.degree. C. Organometallic based slurry binders are avoided and significant cost savings are realized owing to the benign nature of the aqueous based suspensions with respect to the environment.

Abstract: Time-stable yttria slurries, and a method for forming such yttria slurries and articles therefrom are described. The method involves forming an intimate mixture comprising yttria and at least about 0.1 weight percent of a dopant material. An aqueous slurry is then formed comprising from about 1 weight percent to about 95 weight percent of the intimate mixture. The intimate mixture may be formed by heating the mixture to a temperature sufficient to calcine the mixture. Alternatively, the intimate mixture may be formed by heating the mixture to a temperature sufficient to fuse the mixture. The dopant also may be provided as a surface coating on the yttria particles.

Abstract: Mold coatings that are relatively unreactive with titanium and titanium alloys during casting are prepared from yttria slurries, which may contain other refractory materials, an acid and an inert organic solvent.

Abstract: The present invention pertains to a process for preparing ceramic shells as casting molds, wherein a) a pattern of a part to be cast, which pattern can be melted or dissolved out, is prepared, b) the pattern is dipped into a dip-coating composition of a slurry of a refractory material and a binder in order to form a wet coating on the pattern, c) a coarse refractory powder is sprinkled onto the coating, d) the coating is dried, and e) steps b), c) and d) are repeated until the mold shell has reached the desired thickness. A ceramic protective material is added to the dip-coating composition and/or to the coarse refractory powder. Carbon is introduced into the ceramic protective material during the preparation in the molten state. The carbon is able to chemically bind oxygen at the time of the cooling of the casting essentially at mold temperatures above the firing temperature of the casting mold and is thus able to prevent skin decarburization and surface defects in carbon-containing steels.

Abstract: This invention provides a process for preparing a refractory molded article comprising the steps of (a) forming a molded article matrix from an aggregate and the first binder, (b) impregnating the molded article matrix formed in step (a) with the second binder consisting of an alcoholic solution of one kind or two or more kinds of metal alkoxides selected from alkoxides of metals of Group 4A or Group 4B (excepting carbon) and Group 3A or Group 3B of the periodic table and their partial hydrolysates and an alkaline compound of alkali metal or alkaline earth metal (one kind or a mixture of two or more kinds selected from alkoxides, hydroxides and salts of the metal) and (c) drying and firing the molded article matrix at high temperature and also provides a binder for the preparation of such refractory molded article.

Abstract: Emissive compositions are described that can be applied as a coating to the surface of an investment casting mold to increase or decrease the rate of cooling of a casting within the mold. A coating that decreases the rate of cooling of an investment casting within an investment casting mold may comprise a compound having an emissivity less than the emissivity of the mold; a high temperature glass-forming material and a solvent to make a slurry. Similarly, a coating that increases the rate of cooling may comprise a compound having an emissivity greater than the emissivity of the mold; a low temperature glass-forming material and a solvent to make a slurry. Also disclosed in a method of investment casting wherein an emissive composition is applied to the investment casting mold.

Abstract: A method of making a shell mould, particularly for a lost wax casting operation, includes the deposition of an adhesion agent on the pattern before the deposition of layers of ceramic material to build up the mould. The adhesion agent used is preferably a 3% solution of aminosilane in a solvent consisting of ethanol and ethyl acetate in amounts from 25% to 75% of the solvent. The method avoids the phenomenon of detachment at the pattern/ceramic interface.

Abstract: A reinforced ceramic investment casting shell mold and method of making such mold. The ceramic investment casting shell mold includes alternate, repeating layers of a ceramic material and a ceramic stucco defining an overall thickness of the shell mold. A fibrous reinforcing material is disposed in the alternate, repeating layers at an intermediate thickness of the shell mold. The fibrous reinforcing material has high tensile strength at elevated temperature and a coefficient of thermal expansion that is less than the coefficient of thermal expansion of the ceramic material and the ceramic stucco. The fibrous reinforcing material is preferably woven into a twisted yarn and disposed in a generally spiral configuration.

Abstract: Reactive metals, such as titanium or nickel-chrome superalloys containing rare earths, are cast with mold and/or core surface areas formed from an improved slurry. The improved slurry contains yttria to form an inert surface which is exposed to the molten reactive metal. In order to prevent premature gelation of the slurry, the forming of defects in the mold and/or core surface areas, and the forming of defects in the cast article, the slurry contains a source of hydroxyl ions. The source of hydroxyl ions is sufficient to result in the slurry having a pH of at least 10.2 six days after initially mixing the slurry. The source of hydroxyl ions may be a metal alkali or an organic hydroxide. It is believed that the source of hydroxyl ions functions as a hydration suppressant for the yttria to prevent premature gelation of the slurry. The slurry contains a silicon oxide (SiO.sub.2) to alkali ratio which is equivalent to a silicon oxide to sodium oxide (Na.sub.

Abstract: A method for the manufacture of an investment shell mold is disclosed which comprises applying to the surface of a wax pattern at least one layer of slurry formed by dissolving in an organic solvent a soluble organic cellulose derivative containing a dispersed metallic oxide, subsequenty applying to the first layer at least one layer of slurry formed by mixing a refractory powder with a cellulose binder, and thereafter causing the applied slurry layers to set and removing the pattern by the ordinary method.

Abstract: A reinforced ceramic investment casting shell mold and method of making such mold. The ceramic investment casting shell mold includes alternate, repeating layers of a ceramic material and a ceramic stucco defining an overall thickness of the shell mold. A fibrous reinforcing material is disposed in the alternate, repeating layers at an intermediate thickness of the shell mold. The fibrous reinforcing material has high tensile strength at elevated temperature and a coefficient of thermal expansion that is less than the coefficient of thermal expansion of the ceramic material and the ceramic stucco. The fibrous reinforcing material is preferably woven into a twisted yarn and disposed in a generally spiral configuration.