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
• • 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
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/54—Electroplating of non-metallic surfaces
  • C25D5/56—Electroplating of non-metallic surfaces of plastics
• • 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
  • B22F2301/00—Metallic composition of the powder or its coating
  • B22F2301/05—Light metals
  • B22F2301/052—Aluminium
• • 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
  • B22F2301/00—Metallic composition of the powder or its coating
  • B22F2301/10—Copper
• • 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
  • B22F2301/00—Metallic composition of the powder or its coating
  • B22F2301/30—Low melting point metals, i.e. Zn, Pb, Sn, Cd, In, Ga

Definitions

• the invention relates to a process for the production of an open-porous molded body with a modified surface, which is formed with metal and a molded body produced by the process.
• Claim 10 relates to a molded article produced by the method.
• Advantageous embodiments and further developments can be realized with features described in the subordinate claims.
• open-porous body made of a metallic material are used as semifinished product.
• This may be a metal grid, a metal net, a metal mesh, a metal foam, a metal garbage or a semi-finished product formed with metallic fibers.
• the semifinished product may also advantageously be an open-pore shaped body in which a polymer material has been galvanically (electrochemically) coated with a metal.
• a semifinished product produced in this way can be subjected to a thermal treatment in which the organic constituents of this polymer are removed as a result of pyrolysis.
• this removal of organic components may also occur later in a similar timely removal of a binder, which will be discussed in more detail below.
• a coating of the open-porous body with particles of a chemical compound of a metal on surfaces of the resulting open-porous formed with metal molding should also be introduced into the interior of the shaped body, that is to say into the pores or free spaces of the semifinished product.
• the particles of a chemical compound of a metal can be used for the process of coating as a powder, as a powder mixture, as a suspension or as a dispersion.
• the coating of the surface of the semifinished product with a powder, a powder mixture and / or a suspension / dispersion can be effected by dipping, spraying, pressure-assisted, electrostatic and / or magnetic.
• the powders, powder mixtures, suspensions or dispersions used for the coating of the open-pore semifinished product can contain, in addition to particles of a chemical compound of a metal, an inorganic and / or organic binder which is finely distributed in the form of the powder, the powder mixture, the suspension or dispersion a solid powder or dissolved in a liquid phase of a solution containing suspension / dispersion of metallic particles or particles of a chemical compound of a metal.
• the coating of the surface of the semifinished product with a binder in the form of a solution or a suspension / dispersion can be effected by dipping or spraying.
• the thus prepared open-porous molded body is coated as a semifinished product with a powder of a chemical compound of a chemical element.
• This powder contains a chemical compound that can be converted to a metal by thermal reduction, chemical or chemical decomposition.
• the distribution of powder particles can wet with the liquid binder Surfaces and their adhesion to the surface can be improved.
• the application of particles as powder, powder mixture and / or suspension / dispersion can be repeated several times, preferably at least three times, more preferably five times. This also applies to the particular vibration to be performed and possibly the application of a binder.
• the coating of the surface of the semifinished product can also be carried out before the thermal treatment in which the organic constituents of the polymeric material with which the semifinished product has been produced are removed. Subsequent to the application of the particle-containing material, a thermal treatment is carried out in which organic and volatile constituents of the polymeric material and at the same time any binder used are removed.
• sintering is performed in which sintered bridges are formed between the particles of the metal particles formed in the thermal treatment formed in the reduction or decomposition and the metallic surface of the open-porous metallic shaped body.
• the specific surface of the thus coated and sintered open-pore shaped body is to be increased to at least 30 m 2 / l, however, at least 5 times compared to the starting material of the uncoated metallic molded body as a semi-finished product.
• the porous skeleton with a pore size between 450 ⁇ and 6000 ⁇ and a specific surface area of 1 m 2 / l - 30 m 2 / l with particles (particle size d 50 between 0.1 ⁇ to 250 ⁇ ) depending on the application either starting from one side (porosity gradient) or completely filled or the webs of the porous metallic shaped body have been superficially coated.
• the coating with particles can be carried out on different sides of the surface, in particular on opposing surfaces of the semifinished product, with different amounts in order to avoid because to get a different porosity, pore size and / or specific surface area. This can be achieved, for example, by a different number of application of particles as powder, powder mixture or in suspension / dispersion, with or without binder use, on the surfaces arranged on different sides. So can a graded
• Formation of a shaped article produced according to the invention can be achieved.
• the pore size within the applied particle layer of the coated and sintered open-pore shaped body corresponds to a maximum of 10,000 times the particle size used. This can be additionally influenced by the maximum height of the sintering temperature and its holding time, since with increasing temperature and holding time the diffusion-related mass transfer and thus the sintering, which is accompanied by a reduction of the pore volume, is promoted.
• the material with which the molding produced according to the invention is formed should contain a maximum of 3% by weight, preferably a maximum of 1% by weight of O 2 .
• a maximum of 3% by weight preferably a maximum of 1% by weight of O 2 .
• a respectively suitable atmospheric condition for the respective decomposition process can be selected.
• Such an open-porous shaped body produced according to the invention can be used in the field of (i) filtration, (ii) as a catalyst (for example in US Pat
• Ethylene oxide synthesis - Ag-particle coated Ag foam catalyst (iii) electrode material or (iv) support for a catalytic active substance.
• the increase in the specific surface area results in better filtration performance in application (i) since adsorption tendency and capacity are markedly increased.
• Suitable metals for applied particles and semi-finished products with which moldings produced according to the invention can be produced are: Ni, Fe, Cr, Al, Nb, Ta, Ti, Mo, Co, B, Zr, Mn, Si, La, W, Cu, Ag, Au, Pd, Pt, Zn, Sn, Bi, Ce or Mg.
• Chemical compounds of the metals Ni, Fe, Cr, Al, Nb, Ta, Ti, Mo, Co, B, Zr, Mn, Si, La, W, Cu, Ag, Au, Pd, Pt, Zn, Sn, Bi, Ce, Mg, V, by chemical Reduction, thermal or chemical decomposition in a thermal treatment can be converted into particles of the respective metal, in particular their oxides, nitrides, hydrides, carbides, sulfides, sulfates, phosphates, fluorides, chlorides, bromides, iodides, azides, nitrates, amines, Amides, organometallic complexes, salts of organometallic complexes, or decomposable salts for the particle-containing material with which the surface of the present as a semi-finished open-porous shaped body to be coated can be used.
• Particularly suitable as chemical compounds are chemical compounds of: Ni, Fe, Ti, Mo, Co, Mn, W, Cu, Ag, Au
• a suitable decomposition atmosphere which may be inert, oxidizing or reducing, maintained.
• the thermal treatment which is to lead to the chemical reduction, may preferably be carried out at least temporarily until the chemical reduction has been carried out in a reducing atmosphere, in particular a hydrogen atmosphere.
• atmospheres are particularly suitable which contain oxygen, fluorine, chlorine, any mixtures of these gases as well as any mixtures with inert gases, for example nitrogen, argon or krypton.
• the surface properties of an open-porous molded article produced according to the invention can be influenced, for example the thermal resistance, the resistance to corrosion, the chemical resistance, the adhesion a catalytic washcoat and the catalytic functionality.
• a graded transition between the metallic material of the semifinished product and the material of the metal particles formed advantageously also has an advantageous effect.
• different phases can form, as is clear from subsequent embodiments.
• Porosity, pore size and specific surface area can be significantly affected by the morphology of the particles used for the coating.
• particles of small size and dendritic form e.g.
• Electrolyte powder advantageous. Due to their irregular geometry, which allows no gap-free arrangement, adjacent particles form free spaces between contact points and particle bodies, which are partially connected to channels. Furthermore, the use of particles from a chemical compound in thermal decomposition or chemical decomposition creates an additional microporous space left by the volatile component. The proportion of the microporous space in the total pore space is higher, the greater the proportion and thus also the volume requirement of the volatile component of the chemical compound. For the coating with metal oxide particles, therefore, the use of a oxide with a high oxidation state, and consequently a high oxygen content, is advantageous.
• the atmosphere, the holding time and the material-dependent sintering temperature are chosen so that the particles ansaintern mechanically stable to each other and to the semi-finished, but the fine pores are not significantly compacted.
• the powdery binder was first dissolved in water and then added all other components and mixed in a speed mixer 2 x 30 s at 2000 rev / min to a suspension.
• the semi-finished product was sprayed on both sides several times using a wet powder spray method with the prepared powder suspension.
• the suspension is atomized in a spraying device and applied on both surfaces on surfaces of the semifinished product. Due to the discharge pressure from the spray nozzle, the suspension is distributed evenly in the porous network of the semifinished product. The suspension only sticks to the web surface, so that the webs are completely covered with the suspension and the porosity of the semifinished product is largely retained.
• the thus-coated semi-finished product was then dried at room temperature in air.
• a thermal treatment was carried out under a hydrogen atmosphere and then in an oven. For this purpose, the oven is heated at a heating rate of 5K / min.
• the reduction of the silver oxide begins even at below 100 ° C and is completed at 200 ° C and a holding time of about 30 minutes under hydrogen.
• the remaining debinding and sintering process can then be carried out in an oxygen-containing atmosphere, for example air in the temperature range from 200 ° C to 800 ° C with a holding time of 1 min to 180 min.
• the silver oxide was first reduced to metallic silver, which is nanocrystalline.
• metallic silver which is nanocrystalline.
• the porosity is about 93%.
• the surface of the webs is characterized by a high roughness.
• the reason for this is that the applied powder particles are only connected to the surfaces of the semifinished product via sintered necks / sintered bridges, so that the original particle morphology is retained.
• the specific inner surface area (measured by the BET method) of the finished open-porous molded article could be determined by the previously performed process
• the semifinished product was an open-porous nickel shaped body having an average pore size of 450 ⁇ m, with a porosity of about 95%, the dimensions 200 mm ⁇ 80 mm, thickness 1.6 mm (produced by electrolytic
• the underside of the thus coated semifinished product remained uncoated.
• the powder loading in the foam is graded from top to bottom.
• the debindering was carried out in a thermal treatment in an argon atmosphere. For this purpose, the oven is heated at a heating rate of 5 K / min.
• Debinding begins at about 300 ° C and is completed at 600 ° C and a holding time of about 30 min. This is followed by further heating to 1100 ° C with a holding time of 1 h at this maximum temperature, wherein the MoS 2 is decomposed in Mo and S and the sulfur is transported away in the vapor phase by the argon gas stream. Subsequently, the atmosphere was converted to hydrogen during the thermal treatment of argon and further heated. The sintering process took place at a temperature of 1260 ° C to and a holding time of 60 minutes.
• the Mo diffuses out of the powder particles into the web material until the powder particles are firmly connected to the webs of the semifinished product via sintering necks or sinter bridges which form.
• a complete compensation of the element concentration does not take place.
• the porosity is ⁇ 30% and the pore size is in the range 5 ⁇ - 50 ⁇ and increases to the uncoated side of the mold continuously to 95% porosity and a pore size of 450 ⁇ .
• the molybdenum-coated foam webs have a graded phase composition as follows:
• Composition / phases Mo (porous layer on the outside of the web and in the filled pore space)
• the surface of the webs is characterized by a high roughness.
• the reason for this is that the applied powder particles are only connected via sintered necks or sinter bridges with the carrier foam, so that the original particle morphology is maintained.
• the semifinished product was an open-pore shaped body of nickel with an average pore size of 580 ⁇ m, a porosity of about 95%, dimensions of 75 mm ⁇ 70 mm, thickness 1.9 mm (produced by electrolytic deposition of Ni on PU foam) Powder TiH 2 titanium hydride powder having a mean particle size ⁇ 45 ⁇ , a mass of 12 g, a steramide wax having an average particle size ⁇ 80 ⁇ , a mass of 0.12 g and as binder 1% - aqueous solution of polyvinylpyrrolidone with a volume of 20 ml used.
• Powder and steramide wax were mixed for 10 minutes with a Turbula mixer.
• the semi-finished product was sprayed on both sides with the binder solution. It was then fixed in a vibration device and fitted with titanium on both sides. hydride powder sprinkled. The vibration distributes the powder in the porous network of the semifinished product. The binder and powder coating was repeated five times so that the pore spaces were completely filled. The thus treated semi-finished product was then dried at room temperature in air.
• Debinding was carried out under hydrogen atmosphere conditions. For this purpose, the oven is heated at a heating rate of 5K / min. Debinding begins at about 300 ° C and is completed at 600 ° C and a holding time at this temperature of about 30 min. This was followed under vacuum conditions at 700 ° C and 60 min hold time, the decomposition of the titanium hydride to hydrogen and titanium in the thermal treatment. Thereafter, a further heating up to the sintering temperature of 900 ° C at a holding time of 30 min.
• the titanium hydride coated webs of the semifinished product had a graded phase composition following the thermal treatment resulting in sintering as follows:
• Composition / phases Ti (porous layer on the outside of the web and in the filled pore space)
• the porosity of the open-pore shaped article treated in this way is 48% and the specific surface area is 55 m 2 / l.

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• 2017
  • 2017-09-19 DE DE102017216566.9A patent/DE102017216566A1/de active Pending
• 2018
  • 2018-09-14 KR KR1020207011234A patent/KR102612696B1/ko active IP Right Grant
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  • 2018-09-14 EP EP18769696.8A patent/EP3684531A1/de active Pending
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