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
  • B22F7/004—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 comprising at least one non-porous part
  • B22F7/006—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 comprising at least one non-porous part the porous part being obtained by foaming
• • 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
  • B22F3/1125—Making porous workpieces or articles by using decomposable, meltable or sublimatable fillers involving a foaming process
• • 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
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
  • B22F2998/10—Processes characterised by the sequence of their steps

Definitions

• the invention relates to a method for producing foamable metal bodies, being from a powder mixture which is at least one metal powder and at least a gas-releasing propellant powder, which when heated to a temperature splits off gas at or above the decomposition temperature of the blowing agent, a compact body is made.
• the invention also relates to those obtained from the foamable metal bodies Metal foams, also as a component of molded parts and composite bodies.
• the present invention has for its object a method and a Show device of the type mentioned by which the manufacture of foamable metal bodies simplified and / or the variability in Production of foamable metal bodies is enlarged.
• This object is achieved for the method in that the Production of the compact body by thermal spraying of the powder mixture using high-speed flame spraying or cold gas spraying.
• the object is achieved for the device in that the means for producing the compact body from the powder mixture a device for thermal spraying by means of high-speed flame spraying or cold-cold spraying.
• Thermal spray processes are essentially characterized in that they enable uniformly applied coatings of high quality and quality. Coatings applied by thermal spraying can be varied the spray materials and / or the process parameters to different requirements be adjusted.
• the spray materials can basically in Form of wires, rods or can be processed as a powder. There can also be one Aftertreatment should be provided.
• thermal spraying Details of thermal spraying are, for example, the European standard EN 657 refer to.
• a process variant of thermal spraying that has been known for some time provides high-speed flame spraying (sometimes also as an HVOF process [High Velocity Oxy-Fuel]).
• a high-speed flame spraying process can do the high-speed flame spraying first and second generation with medium spray particle speeds of 400 to 500 m / s (measured with a WC-Co spray powder with a grain size - 45 ⁇ m + 10 ⁇ m, i.e. a distribution with respect to the grain diameter of 10 to 45 ⁇ m) and prefers third generation high speed flame spraying Spray particle speeds of 500 to 700 m / s (measured with a spray powder WC-Co with a grain size - 45 ⁇ m + 10 ⁇ m) can be used.
• With cold gas spraying can accelerate the powder particles to a speed of 300 to 1600 m / s become. Speeds of the powder particles are particularly suitable between 500 and 1200 m / s to achieve particularly high application efficiency and layer densities.
• metal powder is used together with one containing the blowing agent Powder by high-speed flame spraying or cold gas spraying processed into a compact body.
• the compact body can be used as a layer or present as a shaped body. Because of the short residence time of the powder (usually this is in the range of a few milliseconds) with high-speed cold gas spraying in the heated carrier gas jet, the blowing agent remains at least in the essentially tied. If desired, it will only be heated up afterwards free to foam.
• the invention provides a simple and versatile method of manufacture of the foamable metal body.
• the so produced Metal bodies can be heated to a temperature equal to or preferred above the decomposition temperature of the blowing agent and then cooling can be used for the production of porous metal bodies or metal foams.
• the decomposition temperature of the blowing agent is not a sharp temperature value but a temperature range. In the context of the invention is therefore under a Temperature equal to or preferably above the decomposition temperature of the blowing agent in these cases a temperature in the decomposition temperature range or preferably understood above the decomposition temperature range of the blowing agent.
• the powder mixture can consist of metal plus blowing agent can be sprayed in almost any mixing ratio. This allows, that the mixing ratio of metal powder and blowing agent powder to each desired conditions is adjusted.
• the powder mixture is injected with a different proportion of propellant. Because through a change The mixing ratio of metal and blowing agent can layers and Structures are injected with a preferably changing propellant proportion (graded layers, structures).
• a proportion of blowing agent in the powder mixture between 0.01 and 1.0% by weight, preferably between 0.05 and 0.5% by weight, particularly preferably between 0.1 and 0.3% by weight.
• the gas-releasing blowing agent powder comprises, as blowing agent, metal hydrides, such as, for example, titanium hydrite (TiH 2 ), carbonates, such as, for example, calcium carbonate, potassium carbonate, sodium carbonate or sodium bicarbonate, hydrates, such as, for example, aluminum sulfate hydrate, alum, aluminum hydroxide or easily evaporating substances such as, for example, mercury compounds or powdered mercury compounds organic substances or mixtures of the aforementioned substances.
• metal hydrides such as, for example, titanium hydrite (TiH 2 )
• carbonates such as, for example, calcium carbonate, potassium carbonate, sodium carbonate or sodium bicarbonate
• hydrates such as, for example, aluminum sulfate hydrate, alum, aluminum hydroxide or easily evaporating substances such as, for example, mercury compounds or powdered mercury compounds organic substances or mixtures of the aforementioned substances.
• the powder mixture can advantageously be sprayed onto a substrate carrier, wherein at least temporarily a relative movement between the substrate carrier and the device for thermal spraying of the powder mixture using high-speed flame spraying or cold gas spraying.
• a substrate carrier for example, with the Powder mixture molded parts are injected, for example the spray gun Device for thermal spraying and / or the substrate carrier are moved.
• the powder mixture can be applied to any suitable substrate carrier in particular on a carrier material made of metal, plastic, ceramic and / or glass be injected.
• the compact body can advantageously be detached from the carrier material are, before a release of gas from the propellant by heating Foaming of the compact body takes place.
• the compact body can be released before the gas is released the blowing agent for foaming the compact body by changing the Pressure and / or temperature are deformed or reshaped.
• compressions For example, extrusion presses or rollers can be used.
• the powder mixture is on the inside injected into a mold that was wholly or partially foamed with metal foam shall be.
• the foaming agent's decomposition temperature is used to manufacture the metal foam.
• At least two layers are injected, wherein at least one layer with the metal powder and gas-releasing blowing agent powder comprehensive powder mixture and at least one further layer with metal powder can be thermally sprayed without gas-releasing blowing agent.
• the powder mixture of metal and blowing agent only in layers between two metal layers be injected.
• Metal foam By heating the compact body using the procedure described above is produced, to a temperature equal to or preferably above the decomposition temperature of the blowing agent and a subsequent cooling can Metal foam can be made.
• the compact is preferably heated Body to a temperature above the melting temperature of the metal or above the target alloy temperature of the metal alloy. In this case it foams as a gas escaping blowing agent on the molten metal. This foam forms after Cool a porous hollow body. So is preferred when decomposing the Blowing agent released gas the metal or the metal alloy as a melt lather up.
• Molded parts can be produced which comprise at least one metal foam.
• composite bodies can be produced which are at least one metal foam Include layer on or between a substrate support.
• For molded parts or composite bodies can in addition to the at least one foamed metal layer at least there is another thermally sprayed layer.
• Titanium hydride (TiH 2 ) is particularly suitable as a blowing agent.
• Titanium hydride can, for example, be sprayed using cold gas spraying together with other metal powders made of aluminum (Al), copper (Cu), nickel (Ni), iron (Fe), titanium (Ti) and alloys that contain one or more of these metals.
• a relatively small proportion of the blowing agent is sufficient to foam the compact body.
• a powder mixture with 0.2% by weight of TiH 2 and with essentially Al as the metal powder leads to a foam body with about five times the volume increase.
• a blowing agent content of 1.0% by weight of TiH 2 increases the volume of Al by more than ten times.
• the gas required for thermal spraying can be nitrogen, helium, argon, neon, Krypton, xenon, a gas containing hydrogen, a gas containing carbon, in particular carbon dioxide, oxygen, an oxygen-containing gas, air, Contain water vapor or mixtures of the aforementioned gases.
• a gas containing hydrogen in particular carbon dioxide, oxygen, an oxygen-containing gas, air, Contain water vapor or mixtures of the aforementioned gases.
• the powdered filler gas carrying a nitrogen, argon, neon, krypton, Xenon, oxygen, a gas containing hydrogen, a carbon-containing gas, in particular carbon dioxide, water vapor or mixtures of the aforementioned gases and mixtures of these gases with helium.
• the proportion of helium in the total gas can up to 90 vol .-%.
• a helium content of 10 to 50% by volume is preferred Gas mixture observed.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Composite Materials (AREA)
• Materials Engineering (AREA)
• Powder Metallurgy (AREA)
• Laminated Bodies (AREA)
• Nozzles (AREA)
• Coating By Spraying Or Casting (AREA)

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• 1999
  • 1999-09-08 DE DE19942916A patent/DE19942916A1/de not_active Withdrawn
• 2000
  • 2000-09-07 AT AT00119602T patent/ATE300378T1/de not_active IP Right Cessation
  • 2000-09-07 EP EP00119602A patent/EP1083013B1/fr not_active Expired - Lifetime
  • 2000-09-07 DE DE50010812T patent/DE50010812D1/de not_active Expired - Lifetime
  • 2000-09-08 US US09/658,264 patent/US6408928B1/en not_active Expired - Fee Related

Patent Citations (3)

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