Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/002—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of porous nature
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/10—Sintering only
  • B22F3/11—Making porous workpieces or articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/10—Sintering only
  • B22F3/11—Making porous workpieces or articles
  • B22F3/1121—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/10—Sintering only
  • B22F3/11—Making porous workpieces or articles
  • B22F3/1121—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers
  • B22F3/1137—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers by coating porous removable preforms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B18/00—Layered products essentially comprising ceramics, e.g. refractory products
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y10/00—Processes of additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y70/00—Materials specially adapted for additive manufacturing
  • B33Y70/10—Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
  • C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
  • C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
  • C04B38/0051—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof characterised by the pore size, pore shape or kind of porosity
  • C04B38/0064—Multimodal pore size distribution
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
  • C04B38/06—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
  • C04B38/06—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances
  • C04B38/0615—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/08—Alloys with open or closed pores
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/00793—Uses not provided for elsewhere in C04B2111/00 as filters or diaphragms
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/38—Non-oxide ceramic constituents or additives
  • C04B2235/3817—Carbides
  • C04B2235/3821—Boron carbides
• • C—CHEMISTRY; METALLURGY
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/38—Non-oxide ceramic constituents or additives
  • C04B2235/3817—Carbides
  • C04B2235/3826—Silicon carbides
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
  • C04B2235/48—Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
• • C—CHEMISTRY; METALLURGY
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
  • C04B2235/54—Particle size related information
  • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
  • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
  • C04B2235/54—Particle size related information
  • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
  • C04B2235/5445—Particle size related information expressed by the size of the particles or aggregates thereof submicron sized, i.e. from 0,1 to 1 micron
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
  • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
  • C04B2235/54—Particle size related information
  • C04B2235/5463—Particle size distributions
  • C04B2235/5472—Bimodal, multi-modal or multi-fraction
• • C—CHEMISTRY; METALLURGY
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
  • C04B2235/606—Drying
• • C—CHEMISTRY; METALLURGY
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  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
  • C04B2235/74—Physical characteristics
  • C04B2235/77—Density
  • C04B2235/775—Products showing a density-gradient
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  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
  • C04B35/62605—Treating the starting powders individually or as mixtures
  • C04B35/62625—Wet mixtures
  • C04B35/6263—Wet mixtures characterised by their solids loadings, i.e. the percentage of solids
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  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
  • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
  • C04B35/632—Organic additives
  • C04B35/636—Polysaccharides or derivatives thereof

Definitions

• the invention relates to a method for producing a porous metallic or ceramic component and one produced using the method
• Porous components are used in a wide variety of technical areas. They are used for filtering or absorbing solid or liquid media, but also as heat exchangers. They often also serve as an isolator or damping element. In many applications an open porous structure is desirable. However, the open porosity leads to losses in strength and stability, so that for many applications it is necessary to use separate supporting frame structures which, although they ensure greater strength, are difficult or impossible to combine with an open-porous foam body with sufficient permanent strength - get tied.
• the procedure is such that a semi-finished product is first prepared in a manner known per se, which has an open-pored structure , which with an open-cell foam body, which is formed from a polymeric material.
• the polymeric material has been provided with a metallic coating or a coating formed with metallic or ceramic particles on the surfaces of webs of the foam body in such a way that an open-pored basic structure has been retained.
• This can be done, for example, with a known CVD or PVD process, galvanically or by the so-called 3 named Schwartzwalder method, in which the webs have been provided with a coating containing metallic or ceramic particles.
• a semi-finished product obtained using the Schwartzwalder process should be dried before further processing to the extent that sufficient green strength has been achieved.
• the corresponding known procedure is described, for example, in US Pat. No. S 0,900,94 B or US Pat. No. 3,111,396 B.
• a blank made from a reticulated open-cell polyurethane foam is preferably used as an open-pored foam body formed from a polymeric material.
• the entire range of commercially classified reticulated foams according to pores per inch (according to ASTM D3576-77) from 8 ppi to 100 ppi can be used as cell size for this purpose, but it is advantageous if coarser foams in the range 8 ppi -30 ppi are used .
• the ppi values can easily be converted into pore sizes in mm using light-optical or computer tomographic methods.
• open-pore structures formed from polymers can also be used, e.g. non-woven fabrics or grids manufactured using additive processes.
• a suspension formed with metallic or ceramic particles, a liquid and a polymeric binder, which additionally contains gas bubbles that have previously been formed in the suspension, with a surface, is then applied to predetermined surface areas of a semi-finished product obtained in this way of the foamed body and formed into a predetermined shape. A part of this suspension penetrates into open pores of the foam body as a semi-finished product in a surface layer area.
• Drying with a thermal treatment is then carried out, in which liquid contained in the suspension is first expelled, then or simultaneously polymeric components, in particular polymeric components of the binder and the polymeric material of the foam body, are removed and sintering is then carried out on this.
• a first volume area with the metal or the 4 ceramic material that comes from the suspension which has a smaller porosity than the porosity of the semi-finished product, which has been obtained exclusively as a result of the gas bubbles contained in the suspension, and adjacent to this first volume area, a second volume area is formed, the is or can also be porous, and the second volume area with the metal or ceramic has been formed from the coating of the webs of the semi-finished product and the metal or ceramic of the suspension, these metals and/or ceramics being materially and positively bonded within the second Volume area are connected to each other.
• the second volume area connects the first volume area with the metallic or ceramic open-pored structure of the open-pored third volume area obtained from the coated foam body, which has a greater porosity than the first volume area, in an edge layer area of the third volume area, which forms the second volume area .
• the suspension with which the first and second volume areas of the component are formed can be produced in a manner known per se.
• a suitable liquid with at least one polymeric binder and a proportion of metallic or ceramic powdered solid can be used for this purpose.
• Gas bubbles can be incorporated into the suspension by mechanical stirring or by another method, for example a procedure as is known from DE 102010039 322 A1.
• gases or gas mixtures can also be used, which can also have an inert effect, so that there is no adverse effect on the respective metal or the respective ceramic with which the component was ultimately formed.
• Binders already used for such suspensions e.g. polyvinyl alcohols, can be used as polymeric binders. Defoamers should be avoided in any case. Water can preferably be used as the liquid. However, other liquids are also suitable, which Kings preferably have a lower boiling point than water.
• a suspension should preferably be used to form the first and second 5 lumen range are used, which has a viscosity of at least 0.1 mPas.
• the suspension should preferably also have a shear-thinning flow behavior with a pronounced yield point.
• the suspension should contain gas bubbles alone or in addition, with a volume fraction of at least 5% and at most 50% of the total volume of the suspension.
• the webs of the semi-finished product should be coated with the same metal or the same ceramic that was used to form the suspension for forming the first and second volume areas. It can be a pure metal of a chemical element, but it can also be an alloy. When using alloys, the alloy composition of the coating of the semi-finished product can differ from the alloy composition of the particles used for the suspension.
• a second volume area can be formed with metal and ceramic material in the composite if the sintering temperatures and thermal expansion coefficients of the different materials allow this.
• the suspension for forming the first and second volume area can be filled into at least one recess, depression, opening, which is formed on the semi-finished product, and/or into the interior of a mold that can be attached to the respective semi-finished product, before the thermal treatment is carried out which the component can ultimately be completed.
• a mold that can be attached to the respective semi-finished product, before the thermal treatment is carried out which the component can ultimately be completed.
• certain surface or edge layer areas of the respective component can be reinforced or connections formed there.
• a mold can be temporarily connected to the semi-finished product or the 6
• Semi-finished product can be inserted into a frame-shaped mold, so that a suspension containing gas bubbles can be filled into at least one gap between the surface of the semi-finished product and the inner wall of the respective mold, in order to form a first volume area there and a second volume area directly next to it by penetration of the suspension into open pores of the semi-finished product to be able to
• a mold can completely enclose the semi-finished product.
• it can also be sufficient to fix a molding tool to a partial area of the surface of a semi-finished product and then to fill the suspension there into the gap or a cavity between the surface of the semi-finished product and the inner wall of the molding tool.
• hollow profiles with a round or square cross-section that can enclose a semi-finished product can be used as a mold.
• corresponding segments of such profiles, such as circular segments can also be used as forming tools.
• the penetration depth of the suspension in the pores of the semi-finished product, starting from the surface of the semi-finished product, can be influenced by external forces, which in turn can selectively influence the thickness or width of an edge layer area that forms the second volume area.
• the thickness or width should be at least 3 mm, starting from the surface of the semi-finished product towards its interior. As already mentioned, this thickness or width can also be selected to be smaller or larger. However, it should be large enough that the three volume areas can be connected to one another sufficiently firmly and a sharp boundary surface between the first and third volume areas can be avoided as far as possible.
• the thickness or width required for this can be based on the cell width or pore size of the semi-finished product and should be at least a factor of 3 of the cell size or pore size of the semi-finished product.
• a semi-finished product alone or a semi-finished product with a mold attached to it can be made to vibrate and/or pressure can be exerted on the suspension.
• a medium gas or liquid
• a medium that is under pressure above the ambient pressure can be used. 7 zen, whereby the higher pressure acts on the surface of the suspension and the suspension is pressed into open pores of the semi-finished product.
• the width or thickness of the second volume area can be influenced. This can also be achieved with at least one vibrator attacking a mold or a semi-finished product.
• a semi-finished product can be used that has a porosity in the range of 60% to 95% and/or a first and/or second volume area on the component with a porosity in the range of 0% to 55% can be formed with the suspension.
• a corrosion-resistant FeCrAl alloy can advantageously be used as the metal.
• Both oxidic and non-oxidic ceramics can be used as ceramic materials.
• a component produced according to the invention has a first volume region
• the first volume region has a smaller porosity than the third volume region, which is formed with the open-porous structure of the metallic or ceramic struts of the semi-finished product, the first volume region exclusively with the metal or the ceramic that / from
• the porosity is determined by the number and size of the gas bubbles contained in the suspension. Adjacent to this first volume area, a second volume area is formed, which can also be porous but also impermeable. The second volume range is associated with the Me
• the third volume area should have a porosity of at least 65% and the porosity in the second volume area, which is arranged between the first and the third volume area, should be smaller than in the first and the third volume area of the component.
• a plurality of first and second volume regions which are arranged at a distance from one another, can be present on a component.
• At least one externally accessible connection for electrical energy or the supply and/or removal of a medium from and/or into the component can be formed at least with the first volume region. It can represent a connection as an electrical contact for an electrical resistance heating element. In the case of an electrical resistance heating element, it is advantageous for a first volume region to have sufficient strength.
• the first volume area can be positively and materially connected to the third volume area via the second volume area and the third volume area can enable an improved heating effect, in particular because of its large specific surface area.
• areas can also be formed on a component that can fulfill a dowel function for anchoring elements, e.g. screws.
• a frame can be formed in which the open-pored structure can be held and protected in a form-fitting and material-locking manner.
• the invention can also be used for the production of components that are to be used in lightweight construction, automobile construction, electrical engineering and aerospace.
• a metal foam plate with two compact, rectangular direct foam contacts was manufactured as a component as follows. To produce the component, a plate was used as a rough, rectangular metal foam with the dimensions 125 mm x 75 mm x 20 mm as a semi-finished product. In this case, two first volume areas should be formed on two sides arranged opposite one another, so that a square overall shape of the finished component of 125 mm ⁇ 125 mm ⁇ 20 mm can be obtained.
• the coarse foam as a semi-finished product had a cell width of approx. 4.5 mm and a density of around 10% of the metal density of the semi-finished material.
• the two first volume areas formed solely with the suspension achieved a sinter density of approx. 50% and there an average pore size of between 100 ⁇ m and 1500 ⁇ m and a porosity of 50% were obtained.
• the production of the coarse foam as a semi-finished product was carried out according to the molding process by coating an open-cell polymer foam with the appropriate cell size using the squeeze-rolling process (Schwartzwalder process). preparation that is commercially available from Zschimmer&Schwarz) and additives (e.g.
• the suspension with which the first and second volume areas are to be formed was produced separately in a batch process.
• the basis is formed by the same suspension composition of metal powder, organic 10
• Binders and rheological additives but this time without defoamers.
• surfactant e.g. a fatty alcohol sulphate preparation from Zschimmer & Schwarz
• Zschimmer & Schwarz a fatty alcohol sulphate preparation from Zschimmer & Schwarz
• the foamed suspension in which gas bubbles were distributed as homogeneously as possible in the suspension, was then filled with a spatula into the free edge areas between the inner wall of the mold and the surface of the semi-finished product.
• the flow behavior of the suspension foamed in this way was adjusted in such a way that it becomes flowable when the mold is gently vibrated by the vibrating plate, but remains motionless without the application of external force. In this way, the penetration of the suspension containing gas bubbles into the pores of the coarse metal foam that forms the semi-finished product can be controlled and a composite area of 1 to 2 cell levels (approx. 4.5 mm - 9 mm) can be set as the second volume area .
• the second volume area has been formed, to which the first and third volume areas have been connected in a form-fitting and material-locking manner, and the second volume area has no porosity or a smaller porosity than the first volume area. Connections for electrical contacting could be formed with the first volume areas. All three volume ranges have been formed with the same metal 11
• a ceramic component is to be manufactured using the same principle.
• a ceramic suspension based on water is prepared. This contains a bimodal SiC grain distribution, produced by mixing SiC powders with an average grain diameter of 0.8 ⁇ m and 3.0 ⁇ m in a ratio of 70:30; also 0.6% boron (carbide) and 11% of a water-soluble polysaccharide (corresponds to 4% carbon after pyrolysis) as a sintering additive. The suspension is adjusted to a solids content of 78%.
• a polyurethane foam with a cell width of 30 ppi (pores per inch) is impregnated with the suspension and the excess suspension is then separated off using a centrifuge.
• a plate measuring 200 mm ⁇ 250 mm ⁇ 10 mm is mentioned as an example, which had two symmetrically arranged rectangular recesses measuring 20 mm ⁇ 50 mm on the outer edge and was used as a semi-finished product.
• These recesses which represent a cavity that at least resembles the interior of a molding tool, were filled with a foamed suspension to form tighter contact terminals.
• the recesses can be made in the foam body, for example, by laser or water jet cutting, and this should preferably be done before the polymer foam is coated, during which the semi-finished product is produced.
• the device consists of a hollow steel cylinder with a length of 182 mm and an external diameter of 70 mm with a wall thickness of 2.9 mm.
• This cylinder has a connection for the controllable compressed air supply.
• a metal disc with a concentric nozzle At the end of the pipe there is a metal disc with a concentric nozzle, which can also be used as a hose connection.
• the back of the tube is also sealed with a metal disk that has a through-hole with a diameter of 10 mm.
• Inside the steel cylinder is a porous hollow cylinder with an outer diameter of approx. 25 mm and a wall thickness of approx. 2 mm, clamped between the two covers by sealing rings.
• the porosity of the stainless steel tube is around 43%.
• a static mixer from the SMX series (from Sulzer Chemtech AG) with a diameter of approx. 20 mm is located in the core of the tube.
• the metal powder suspension is passed through this porous inner tube with the static mixer, while at the same time it is impinged by the compressed air at a pressure of approx. 0.3 MPa and an air volume flow of approx. 600 ml/min. This creates uniform air bubbles in the suspension.
• the suspension foamed in this way can be filled into the recesses already formed in advance on the semi-finished product by switching the foaming device on and off.
• the edge area, which forms the second volume area, should be about 4 mm thick in order to achieve a form-fitting and cohesive bond between the second and third volume area after sintering.

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• 2021
  • 2021-05-11 DE DE102021204741.6A patent/DE102021204741A1/de active Pending
• 2022
  • 2022-05-10 WO PCT/EP2022/062633 patent/WO2022238399A1/de active Application Filing
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