Abstract: An electrode assembly for a solid oxide fuel cell, the electrode assembly including a porous ceramic oxide matrix and an array of fluid conduits. The porous ceramic oxide matrix includes a labyrinth of reinforcing walls interconnected to one another. Each of the fluid conduits is formed from the porous ceramic oxide matrix and has an external surface with a plurality of struts projecting outwardly therefrom and an internal surface defining a first passage for flowing a first fluid therethrough. The struts are configured to connect the fluid conduits to one another and the external surfaces and the struts define a second passage around the fluid conduits for flowing a second fluid therethrough.

Abstract: The present invention provides a method for producing a rare earth sintered magnet, capable of reducing variation in magnetic characteristics of a rare earth sintered magnet and suppressing deformation of the rare earth sintered magnet.

Abstract: A process for fabricating hollow metal shells such as Be or Al filled with a selected gas such as D or T. An organic preform is coated with a slurry of organic binder and metal powder of Be or Al. The coated preform is heated to remove the preform and any organics to form a hollow shell which is then fired at an elevated temperature in a gas so as to seal the shell and capture the gas inside the sealed shell.

Abstract: Forming a wear- and corrosion-resistant coating on an industrial component such as a chemical processing or nuclear power valve component by applying a cobalt-based dilution buffer layer to an iron-based substrate by slurry coating, and then applying by welding a cobalt-based build-up layer over the cobalt-based dilution buffer layer. An industrial component having a dilution buffer layer and a welding build-up layer thereover.

Abstract: A method for preparing an article is disclosed. The method comprises compacting a mixture of a first pre-alloyed powder and a lubricant to thereby form a green part having a green strength sufficient to permit mechanical handling; applying a slurry to a surface of the green part to thereby form a slurry coated green part, wherein the slurry comprises a second pre-alloyed powder, a binder, and a solvent; and heating the coated green part to a temperature below a solidus temperature of the first pre-alloyed powder and between a solidus temperature and a liquidus temperature of the second pre-alloyed powder to thereby solid state sinter the first pre-alloyed powder into a sintered core and to liquid state sinter the second pre-alloyed powder into a continuous alloy coating over the sintered core.

Abstract: A method for preparing a porous metal article using a powder metallurgy forming process is provided which eliminates the conventional steps associated with removing residual carbon. The method uses a feedstock that includes a ferrous metal powder and a polycarbonate binder. The polycarbonate binder can be removed by thermal decomposition after the metal article is formed without leaving a carbon residue.

Abstract: A method for preparing a metal-based part, the method comprising applying a slurry to a surface of a temporary substrate to thereby form a slurry-coated temporary substrate, wherein the slurry comprises a Co-, Ni-, or Fe-based metal-based material, a binder, and a solvent; drying the slurry-coated temporary substrate to remove the solvent and to thereby form a coating layer having green strength; heating the coating layer to remove the binder; heating the coating layer to sinter the metal-based material into a continuous metal alloy layer; and separating the substrate from the coating layer. A powder metallurgy preform comprising a powder metallurgy green coating on a preform substrate.

Abstract: A process for producing powder green compacts includes centrifugally compacting a slip containing a material powder, a binder resin and a dispersion medium in a mold, into a compact containing the material powder and the binder resin. A process for producing sintered compacts includes sintering the green compact. A powder green compact contains a material powder and a binder resin, the binder resin being present between particles of the material powder and binding the material particles. A sintered compact is obtained by sintering the green compact.

Abstract: The invention provides a process of making porous structures or materials, including the colloidal processing (e.g. slip casting, pressure casting, tape casting or electrophoretic deposition) of solid particle emulsions to form a green body that can be directly sintered without a de-binding step.

Abstract: The present invention provides a method of gel-casting WC—Co cemented carbide powder, where the resulting gelled body can be of complex shape and has a high green density, a good homogeneity and sufficiently good mechanical properties for the gelled body to be demolded and dried without significant shape-distortions and cracking. The method relates to the forming of a gelled body through the gelling of an aqueous slurry of WC—Co cemented carbide powder with good dispersion characteristics, where the gelling is achieved by the temperature induced polymerization reaction between a monomer and a cross-linker, catalyzed by a free-radical initiator. By further subjecting the body to drying, heating, and sintering, a dense cemented carbide body is obtained.

Abstract: A sintered cemented carbide body (e.g., a cutting tool) and a method of making the same. The sintered cemented carbide body includes tungsten carbide, a binder phase of at least one metal of the iron group or an alloy thereof, and one or more solid solution phases. Each one of the solid solution phases has at least one of the carbides and carbonitrides of a combination of zirconium, niobium, and tungsten. The method includes the steps of providing a powder mixture that contains tungsten carbide, a binder metal powder comprising at least one metal of the iron group or an alloy thereof, and at least one of the carbides and carbonitrides of both zirconium and niobium including a powder of the carbides or carbonitrides of zirconium and niobium, forming a green compact of said powder mixture, and vacuum sintering or sinter-HIP said green compact at a temperature of from 1400 to 1560° C.

Abstract: A green article comprising an A-B powder mixture and methods of manufacturing such green articles and corresponding sintered articles are disclosed. The A-B powder mixture consists of a minor volume fraction of a relatively fine powder A and a complementary major volume fraction of a relatively coarse prealloyed powder B wherein the A-B powder mean particle size ratio is at least about 1:5. Metal powder A consists of one or more elemental metals or alloys which has a melting or solidus temperature above the highest sintering temperature at which the A-B powder mixture may be sintered without slumping. Prealloyed metal powder B consists of one or more alloys which are amenable to supersolidus liquid phase sintering. Green articles made from the A-B powder have a wider sintering temperature window than do articles made from prealloyed metal powder B alone.

Abstract: The present invention relates to economic and environment-friendly slurries and their preparation, handling, and spray drying for the production of cemented carbide based hard metals. The slurry is ethanol-water based and contains metallic and metal carbide raw materials as well as polyethylene glycol (PEG) and a very low concentration of polyethylenimine (PEI). The concentration of PEI is 0.01-<0.1% of the raw material weight. As a result, low-viscous slurries are produced which require less use of ethanol, energy, manpower and equipment time in their preparation, handling, and spray drying.

Abstract: A method for preparing compositionally graded metallic plates and compositionally graded metallic plates suitable for use as interconnects for solid oxide fuel cells are provided. The method of the invention, utilizing powder metallurgy, enables making metallic plates of generally any desired composition to meet the corrosion requirements of fuel cells and other applications, and enables making metallic plates of graded composition from one surface of the plate to the other. A powder of the desired alloy composition is obtained, then solvents, dispersants, a plasticizer and an organic binder are added to form a slip. The slip is then formed into a layer on a desired substrate that can be flat or textured. Once dried, the layer is removed from the substrate and the binder is burned out. The layer is sintered in a reducing atmosphere at a set temperature for a predefined duration specific to the materials used and the desired final properties.

Abstract: A porous metal body having a foam structure of 500 ?m or less in average pore diameter, wherein the skeleton is composed of an alloy primarily including Fe and Cr, and Cr carbide or FeCr carbide is uniformly dispersed in the texture. The metal porous body is produced by preparing a slurry primarily containing an Fe oxide powder having an average particle diameter of 5 ?m or less, at least one powder selected from metallic Cr, Cr alloys, and Cr oxides, a thermosetting resin, and a diluent, applying a coating of this slurry to a resin core body having a foam structure, performing drying, and thereafter, performing firing in a non-oxidizing atmosphere so as to produce a metal porous body having the aforementioned skeleton structure.

Abstract: A hard metal grade powder is produced from hard material, metal binder, and non-water-soluble pressing aid components, by forming a slurry containing the components and pure water as a liquid phase and then drying the slurry. Here, the hard material and metal binder components are first milled in water, to form a slurry. Then the pressing aid components are added to the slurry in the form of an emulsion produced with the aid of an emulsifier with the addition of water.

Abstract: The specification and drawings describe and show embodiments of the present invention in the cesium vapor emitter and the method of fabricating the same. More specifically, the cesium vapor emitter of the present invention includes a housing having at least one chamber therein and at least one channel, wherein the channel has a size wide enough to introduce a desired amount of cesium vapor, a cesium reservoir placed in the chamber, wherein the cesium reservoir is filled with a cesium pellet and a plug located between the cesium pellet and the channel, thereby emitting the cesium vapor from the cesium pellet through the channel, and a stopper securing the cesium reservoir in the chamber, so that the cesium vapor is emitted through the channel.

Abstract: In a process for handling green compacts made from a rare earth metal-based magnetic alloy powder by a press machine to slide, on a sintering support plate, the green compacts, the support plate used has a surface roughness degree Ra in a range of 0.6 to 47 &mgr;m. At a first step, the green compacts are disposed in a first position near a final transport position, and at a second step, the said green compacts disposed in the first position are slid on the sintering support plate and disposed in the final transport position. Thus, by using the support plate having a surface roughness degree in a particular range, the green compacts made from the rare earth metal-based magnetic alloy powder can be sintered without occurrence of the deposition of the green compacts to the support plate, the chipping of the green compacts and the like. In addition, the efficiency of operation of the press machine can be increased.

Abstract: An improved X-ray tube target comprises a refractory metal target substrate and a refractory metal focal track applied to the target substrate by a tape casting process. The X-ray tube target comprises a refractory metal target substrate and a refractory metal focal track formed on the target substrate to form a focal track/target substrate interface plane that varies less than about ±0.13 mm.

Abstract: An aspect of this invention is an electrode rod for spark alloying, comprising a compact of a first powder of a first component which comprises a metal selected from a group of Fe, Co, Ni, metals of 4a, 5a and 6a of the periodic table and Si, and a second powder of a second component which is capable of self-propagating high temperature synthesis to form with said first component carbide, nitride, boride, silicide or intermetallic compound, said first and second powders being mixed intimately with each other and formed into an axial rod.

Abstract: A method of manufacturing a hollow piston including: fixing a core insert formed of a non-metallic material in a desired location within a mold cavity, injecting a mixture of non-metallic binder material and metal particles into the cavity so as to surround at least a portion of the core insert and form a piston, and eradicating the core insert from the piston.

Abstract: A composition for forming molded metal containing articles having improved stability. More particularly, a corrosion resistant composition for forming injection molded articles having a sodium silicate corrosion inhibiting additive. The corrosion inhibitor prevents metal oxidation when a metal containing powder is mixed with a water based binder, providing stability to the article and preventing generation of hydrogen gas. This significantly enhances the shelf life of the moldable composition prior to molding.

Abstract: A method of producing an R--Fe--B-based, sintered permanent magnet, wherein R is at least one rare earth element including Y, having a small oxygen content. A coarse alloy powder prepared by a reductive diffusion method is milled and recovered into a solvent to form a slurry. The slurry is wet-compacted to form a green body which is then sintered after removing the solvent. The milling, recovering, wet-compacting, solvent-removing and sintering steps are carried out while preventing the powder, slurry and green body from being brought into contact with air to minimize the oxygen content in the final sintered permanent magnet. The sintered permanent magnet produced has a high density and a high magnetic properties due to a low oxygen content.

Abstract: Shaped article replicas which are proportionately accurate replicas of a shaped article and which are equal, greater or smaller in size than said shaped article are made by preparing a swellable polymer replica of said shaped article; immersing said swellable polymer replica in a swelling agent system under conditions which will enlarge said polymer replica to a predetermined extent; forming a casting mold of such enlarged polymer replica; making a powder compact in said casting mold and heating said powder compact to produced a proportionately accurate solid replica of a predetermined size.

Abstract: The invention relates to the field of ceramic and hard metal industries and concerns a process for manufacturing hard metal parts, in particular th having a complex geometry, such as those used for example as machining tools and wear elements. The object of the invention is to create a process which allows the manufacture of hard metal parts with a complex geometry by using a stable dispersed hard metal-binder suspension, wherein the binder is a thermoplastic binder having a viscosity of 3 to 6 mPa s, and without using an organic solvent to eliminate the binder. For that purpose, a process is disclosed wherein a hard metal powder having an average grain size smaller than 2.0 .mu.m is mixed with a liquefied thermoplastic binder, with viscosity of the mixture being set upon a value of at least 100 mPa s and up to 4,000 mPa s during the whole production and treatment process.

Abstract: A method of making flowable tungsten/copper composite powder by milling an aqueous slurry of a mixture of the desired weight ratio of tungsten powder and copper oxide powder and, optionally, a small amount of cobalt powder, spray-drying the slurry to form spherical, flowable agglomerates, and reducing the agglomerates in a hydrogen atmosphere.

Abstract: A process is provided for the manufacture of porous metal components. The process involves preparing a colloidal suspension comprising a metal-containing powder in admixture with a binder system, and a plasticizer in an organic solvent. Optionally, a particulate pore forming agent may be added to the suspension. The suspension is cast into a thin sheet and air dried to thereby form a tape. The tapes are layered and formed by compacting at predetermined pressures to laminate the tapes, thus forming a green body. Optionally, a second pore-forming agent may be introduced between, or associated with, the tape layers. The green body is heated at a controlled rate to form a brown body, and finally sintered under controlled conditions to produce the finished component.

Abstract: The porous metallic material of the present invention has an overall porosity of 80 to 99%, and a skeleton in a three dimensional network structure which is entirely composed of a sintered metal powder having a porosity of 10 to 60%. The specific surface area is very high, for example, 300 to 11000 cm.sup.2 /cm.sup.3. The porous metallic material can be reinforced by a reinforcing plate. The porous metallic material is also suitable for an electrode of an alkaline secondary battery and enables achievement of increases in the life and the amount of the active material contained therein. The porous metallic material can be produced by preparing a foamable slurry containing a metal powder, forming the foamable slurry, drying the formed product, preferably after foaming, and finally burning the dry formed product.

Abstract: Methods for making, methods for using and articles comprising cermets, preferably cemented carbides and more preferably tungsten carbide, having at least two regions exhibiting at least one property that differs are discussed. Preferably, the cermets further exhibit uniform or controlled wear to impart a self-sharpening character to an article. The multiple-region cermets are particularly useful in wear applications. The cermets are manufactured by juxtaposing and densifying at least two powder blends having different properties (e.g., differential carbide grain size or differential carbide chemistry or differential binder content or differential binder chemistry or any combination of the preceding).

Abstract: A device for the production of a green from slurry by solidification after injection into a mold having a temperature of less than 0.degree. C. The device includes a mold having a jack wherein moveable parts of the jack ensure closure thereof and which are housed within a gas-tight vessel. A distributor for dry gas with a dew point lower then the temperature of the mold emits a gas current into the vessel through apertures. A chute conducts the green towards an exit aperture and to a receiving member outside the vessel.

Abstract: An unsintered aluminum nitride body including:(a) 1 to 5 weight percent of a vitreous solid of boria, alumina, and calcia in the proportions of (1) boria between 3 and 25 weight percent, (2) alumina between 10 and 50 weight percent, and (3) calcia between 40 and 80 weight percent; and(b) aluminum nitride powder as the balance of the aluminum nitride body.The invention further relates to a method of forming the unsintered aluminum nitride body and then sintering it at a temperature between 1550 and 1650 degrees Centrigrade so as to form a dense, thermally conductive aluminum nitride body.

Abstract: A method for forming molten carbonate fuel cell (MCFC) anodes by adjusting the reaction condition of pack cementation is disclosed. The method includes the steps of embedding a base metal sheet containing at least Ni in a pack containing alloy metal powder, an activator and a filler, pre-heating the pack to remove the organic material included in the base metal sheet, and maintaining the pack under a H.sub.2 /N.sub.2 atmosphere at a temperature of 500.degree. C. to 800.degree. C. for one to eight hours to form a Ni alloy. The method has a simplified procedure and is very useful to manufacture MCFC anodes having a very low creep deformation rate while porosity is in an appropriate range.

Abstract: A method of preparing a durable air-permeable mold having dimensional accuracy and without cracks clue to the segregation of the ingredients of the aggregate and without a surface irregularity, which comprises compounding 100 parts by weight of an aggregate obtained by compounding metal powders with metal oxide powders in a weight ratio of 5:95 to 30:70, the metal of said metal oxide powders being the same as that of the metal powders, 80% or more of said metal powders and said metal oxide powders having grain sizes of 300 .mu.m or less, with 10 to 35 by weight of an auxiliary hardening material that is softened and melted during the sintering process, and 10 to 25 by weight of a binder that contains an evaporable component, mixing them to form a slurry mixture, pouring it in a pattern mold to obtain a mold, drying the thus-obtained mold, and sintering the dried mold in an oxidative atmosphere at a temperature of 600.degree. to 1200.degree. C.

Abstract: A method for forming a wear surface on a metal substrate has a slurry which includes wear resistant particles, powdered steel, and binder system positioned on the metal substrate by retaining walls for a time sufficient for drying the slurry and forming a composite material of preselected thickness "T". The retaining walls are then removed and the substrate and the composite material are heated and passed through a rolling mill compressing the composite material.

Abstract: Disclosed is a stainless steel member with a high corrosion resistance suitable for a structural member used in highly corrosive environments, such as an edge seal plate of a molten carbonate fuel cell. This stainless steel member includes a base material consisting of stainless steel containing chromium, and a corrosion-protective layer formed on the surface of the base material. In this corrosion-protective layer, a granular heterophase containing chromium is precipitated in an ordered alloy consisting of aluminum and the constituent elements of the base material.

Abstract: A method for manufacturing a sintered body by a) forming a slurry comprising a powder mixture, a dispersant providing steric stabilization for the powders and an organic solvent with a possible addition of one or more soluble polymers; b) transferring the slurry into a mold; and c) changing the temperature sufficient to cause gelation of the sterically stabilized suspension to form a green body. The method also includes d) removing the green body from the mold; e) transferring the green body to a chamber where the gelation temperature can be maintained and the pressure decreased to facilitate removal of the solvent to form a dried body; f) heating the body for a time sufficient to substantially remove the dispersant from the body and; g) sintering the body. The sintered body can be an insert for metal cutting tools.

Abstract: The present invention presents a method of processing ferrous powder materials to produce small component parts exhibiting excellent soft magnetic properties, in particular, residual magnetic flux density. The processing steps involve, in part, mixing with a binder, dewaxing or presintering at a temperature higher than in the conventional dewaxing process, followed by final sintering and a further conversion sintering, at a temperature lower than in the conventional sintering process, to produce parts having density values of over 96% theoretical density and excellent soft magnetic properties. The invented method is suitable for producing small component parts having sufficient strength and excellent soft magnetic properties to make them suitable for miniaturized electrical and electronic equipment.

Abstract: The finished metallic material of this invention is constituted by an agglomerate of finely divided metallic powder, the grains of which are bonded together by means of an organic substance, the volume of such substance being comprised between 0.5 and 7% of the total volume of the material. In order to obtain said material, the metallic powder is mixed with the organic substance, the mixture is moulded under high pressure and after removal from the mould, the material is heated in order to harden the organic substance. The material is employed to advantage for elements constituting horological articles.

Abstract: A porous metal block for selectively removing solder or braze from a substrate is disclosed. The block comprises a plurality of protrusions which absorb solder or braze through capillary action. The number and dimensions of the protrusions vary depending on the application. Also disclosed is a process for making such a block involving a unique two steps sintering process.

Abstract: A process for reaction injection molding of ceramic articles is disclosed. The process comprises (a) injecting a fluid, non-dilatant mixture comprising a ceramic powder, a metal powder or mixtures thereof, and a curable ceramic precursor that is a liquid below its curing temperature, into a heated mold, (b) curing the ceramic precursor to produce a hardened molded article, (c) heating the hardened molded article under a suitable atmosphere to a temperature sufficient to convert the ceramic precursor to a ceramic, and (d) sintering the ceramic to the desired density.

Abstract: The present invention is a method of molding the cutter bars for refiner plates used in treating pulp slurry in the paper processing industry including impressing in a mold the form of a refiner plate or refiner plate segment, pouring the base plate or pouring the base of the refiner base plate segment. The sand surfaces in the mold which will be in contact with the metal to form the perpendicular surfaces of the cutter bars relative to the refiner plate are then treated with a slurry consisting of an alcohol or water carrier into which powdered brittle metal alloys have been introduced such as titanium, boron, carbon, vanadium, chromium, niobium, tungsten, molybdenum and cobalt 10 microns or less in size in the pure or ferro alloy state. The powdered metal alloy slurry is then dried in one of a number of acceptable ways and the cutter bar base metal is then superheated to a temperature higher than its melting point, after which the molten metal is poured into the mold.

Abstract: A process for producing porous articles from metal powders. A slurry including metal powders is deposited on a horizontally moving surface. The slurry/moving surface combination is passed through an evaporating zone, a calender zone and a sintering zone to form the desired article. The article is then separated from the moving surface.

Abstract: A method of manufacturing a porous electrode for a molten carbonate fuel cell comprises the steps of: pulverizing an Al-base intermetallic compound: mixing Ni powders with the pulverized intermetallic compound to form a slurry which contains Ni powders and the pulverized intermetallic compound, the pulverized intermetallic compound serving as a reinforcement; shaping the slurry like a sheet or a tape; and sintering the sheet or tape-like slurry to form the porous electrode.

Abstract: A method and apparatus for injection molding of ceramic suspension is disclosed wherein an elastomeric bladder is disposed within a mold cavity of a mold. The elastomeric bladder, in a relaxed state, can be tubular or can be formed by bonding together sheets of material. A ceramic suspension is injected into the elastomeric bladder, whereby the elastomeric bladder is distended. Distention of the elastomeric bladder applied a significant force to the ceramic suspension for preventing jetting and formation of knit lines within the ceramic suspension. The ceramic suspension distends the elastomeric bladder until the mold cavity is filled. The ceramic suspension is then exposed to conditions sufficient to cause the injected ceramic suspension to form a molded ceramic greenware composite. The molded ceramic greenware composite can then be removed from the mold for drying and for debindering and densification to form a finished ceramic part.

Abstract: Dense, flaw free, complex, 3-dimensional, metal or refractory shapes are formed by preparing a low viscosity, pourable aqueous-based suspension. The aqueous suspension preferably contains ceramic or metal particulates, water, and a compatible mixture of additives for performing dispersant, cryoprotectant, and strength enhancing functions. The low viscosity slip is cast or injection molded at low pressure into a complex mold, frozen, demolded, and freeze dried without the formation of a continuous liquid phase. The green part is subsequently sintered by conventional techniques to achieve a dense part.

Abstract: A mold for slip casting comprising a compact formed out of a mixture having an organic matter and powders, the organic matter being capable of being extracted by supercritical fluid and the powders being incapable of being extracted by the supercritical fluid, and furthermore, a method for slip casting comprising a compact formed out of an organic matter capable of being extracted by supercritical fluid and having a melting point of 0.degree. to 150.degree. C. The organic matter is any one selected from the group of methyl carbonate, t-butyle alcohol, stearic acid stearyl alcohol and paraffin.

Abstract: In the method of invention, the formability is imparted to the slurry of a metal or ceramic powder by employing a porous mold and removing the dispersion medium through the evaporation or thermal decomposition thereof, or by using a silazane oil as the dispersion medium and curing it by heating. Since the phase change usually accompanying volume change does not occur in the dispersion medium, strain and deformation rarely occur in the molded body. As result, the sintered body obtained has high dimensional accuracy.

Abstract: A continuous process for producing strip products which comprises forming an aqueous slurry of a mixture of a metal powder and a film-forming cellulose derivative and producing from this slurry a self-supporting strip. This self-supporting strip is fed onto an endless moving belt by which the strip is transported into and through a sinter furnace. A tensile force is applied to the sintered strip in the direction of travel of the strip, and this tensile force is controlled such that the speed at which the strip leaves the furnace is greater than the speed at which the strip enters the furnace by an amount related to the expected or actual increase in strip length occasioned by expansion of the strip during the sintering process.

Abstract: A method for casting a metal or ceramic powder which comprises casting a slurry of the metal or ceramic powder suspended in a dispersion medium containing at least 10 wt. % of a liquid extractable with a supercritical fluid or a liquefied gas into a porous mold, keeping the slurry placed in the porous mold at a temperature not lower than the melting point of the dispersion medium, and extracting at least 10 wt. % of the dispersion medium with the supercritical fluid or liquefied gas to impart a formability to the extracted body.In the method of the invention, since the volume change of the dispersion medium due to phase change does not occur, the internal strain and deformation of the molded body occur little. As a result, the sintered body obtained has a highly dimensional accuracy.

Abstract: A light-weight yet sturdy ceramic article, is manufactured by initially forming at least one fugitive core including a main portion and at least one holding portion projecting from the main portion and then positioning the fugitive core in a mold cavity bounded by a multitude of bounding surfaces so that the holding portion holds the main portion at predetermined spacings from all of the bounding surfaces. This is followed by filling the mold cavity around the fugitive core with a dense slip constituted by ceramic or metal particles in mixture with a liquid medium to form a ceramic or metal preform embedding the fugitive core in its interior and freezing the ceramic or metal preform, then the fugitive core is dissolved and escapes from the interior of the frozen ceramic or metal preform and finally the ceramic preform is converted into the ceramic article.