US3232754A - Porous metallic bodies and fabrication methods therefor - Google Patents

Porous metallic bodies and fabrication methods therefor Download PDF

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Publication number
US3232754A
US3232754A US150826A US15082661A US3232754A US 3232754 A US3232754 A US 3232754A US 150826 A US150826 A US 150826A US 15082661 A US15082661 A US 15082661A US 3232754 A US3232754 A US 3232754A
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aluminum
sintering
copper
powder
mixture
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US150826A
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Storchheim Samuel
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Alloys Research and Manufacturing Corp
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Alloys Research and Manufacturing Corp
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Priority to US150826A priority Critical patent/US3232754A/en
Priority to CH1297162A priority patent/CH447620A/fr
Priority to GB41959/62A priority patent/GB1015491A/en
Priority to DE1962A0041565 priority patent/DE1458315B2/de
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    • 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
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0408—Light metal alloys
    • C22C1/0416—Aluminium-based alloys
    • 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
    • B22F3/1035—Liquid phase sintering
    • 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
    • B22F3/24—After-treatment of workpieces or articles
    • B22F3/26—Impregnating
    • 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
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0408—Light metal alloys

Definitions

  • the conventional practice in making self-lubricating bearings is to press metal powders, such as a copper and tin mixture, into a green compact which is then sintered to form a porous coherent body. Small percentages of graphite and volatile organic compounds are usually included in the powder mixture for the purpose of controlling porosity during the sintering operation. The resultant porosity in the sintered hearing may run as high as 90% by volume. After coining the sintered bearing to its final size it is impregnated with oil. In operation, the oil is exuded from the pores of the bearing to lubricate the shaft journaled therein. As the bearing heats up, the flowrate of oil increases, hence lower running temperatures favor a longer effective bearing life.
  • porous aluminum bodies having porosities ranging from 10 to 50 volume percent, the bodies being controlled in dimension and being characterized by improved crush strength and good deflection.
  • a significant feature of the invention is that it facilitates the mass production of commercially acceptable aluminum alloy self-lubricating bearings having advantages lacking in bearings made of other metals.
  • Aluminum allays have a relatively high thermal conductivity, thereby improving heat dissipation. At the same time they have both a low modulus and softness so that the bearings will not bear overly hard and will wear when subjected to localized pressure. As a consequence, localized pressure is relieved and the deleterious effects of misalignment and shaft deflection are reduced.
  • a soft material such as aluminum will embed grit and thus aid in avoiding hot spots leading to hearing failure.
  • aluminum bearings have excellent corrosion resistance and high fatigue strength.
  • Another object of the invention is to provide light weight aluminum bodies which are highly useful as structural elements, particularly in the cryogenic field, for aluminum is not rendered brittle at exertmely low temperatures.
  • porous aluminum body may be formed into a small wafer for use as a nicotine filter in a cigarette or any smoking appliance.
  • Still another object of the invention is to provide an improved process for fabricating porous aluminum bodies which process makes use of relatively light compacting pressures in conjunction with unlubricated dies, lubricants being added only to the powder mixture in a manner whereby discoloration and oxidation of the sintered parts do not occur.
  • FIG. 1 is a sectional view of a furnace for carrying out sintering in accordance with the invention.
  • PEG. 2 is a separate view, in longitudinal section, of the retort used in the furnace.
  • FIG. 3 shows the closure for the retort, in side view.
  • FIG. 4 shows the same closure in end view.
  • FIG. 5 is a perspective view of the boat or covered tray placed within the retort to house the bearings.
  • FIG. 6 is a graph explanatory of the invention, showing a copper-aluminum phase diagram.
  • FIG. 8 is a graph showing the effect of the copper content and particle size on the bearin gs.
  • FIG. 9 is a photograph of the pore structure using one type of copper powder.
  • FIG. 10 is a photograph of the pore structure using another type of copper powder.
  • the process for making porous aluminum alloy products involves the steps of compacting a powder mixture into the desired form, and the green compact under such condition of temperature as to cause sintering of the powders into a coherent but porous mass.
  • molten aluminum is atomized in a helium atmosphere and cooled in the same atmosphere, oxidation thereby being avoided.
  • the copper powder I prefer to use relatively coarse powder of good purity coupled with a high density and good flow rate. Suitable for this purpose is an electrolytic copper powder (type O) which in screen analysis has 60 to of +100 mesh size, 20 to 35% of +150 mesh size and .25% maximum of l50+200 mesh size.
  • the lubricant which is supplied to the powder mixture is preferably in the form of Sterotex which is added in small amount solely for the purpose of eliminating die friction problems and the prevention of powder pick-up by the die. I have found that the addition of at least 1% weight percentage of Sterotex powder acted to limit the pick-up problem, whereas optimum compaction was obtained at 2%.
  • Sterotex is a refined vegetable oil produced by Capital City Products Co. of Columbus, Ohio, and has the following properties and characteristics.
  • the helium aluminum powders are thoroughly mixed with the powders in a ratio in which the copper content is not in excess of 5% by weight and preferably in which the copper content is in the range of 1 /4 to 2% weight percent copper.
  • the Sterotex lubricant is added to this aluminum-copper mixture in a range of 1 to 3% weight percentage.
  • the nature of the powder mixture is such that the green compact is sufficiently consolidated for further handling without loss f integrity.
  • the furnace used for this purpose is illustrated in FIG. 1 and comprises an insulated chamber 10, into which is insertable a retort 11, the chamber being provided with suitable heating element 12 and a circulating fan 13.
  • the retort 11 is in the form of an elongated rectangular box the rear end of which extends outside of the furnace, the rear end being sealed by a removable closure 14 provided with a gasket 15.
  • the retort is filled with an atmosphere of hydrogen through an inlet tube 16, the hydrogen passing out of the retort and being burned off through an outlet jet 17.
  • the temperature in the retort is measured by means of a sheathed thermocouple 18. This is best seen in FlGS. 3 and 4.
  • the closure is provided with three bores 16a, 17a and 8a for re eiving the tubes passing therethrough.
  • a boat 18 Placed within the retort 11, adjacent the front end thereof, is a boat 18 provided with a removable cover 19, locating pins 20 projecting from the cove-r which are receivable in correspondingly positioned apertures in the side walls of the boat to hold the cover in place.
  • the boat is divided by a partition wall 21 into a main section for accommodating green compact bearings 22 to be. sintered, and an auxiliary section filled with aluminum powder acting as a getter to pick up oxygen and moisture.
  • the arrows in FIG. 2 indicate the direction of hydrogen flow in the retort.
  • the covered boat 18 is not sealed from the hydrogen, but free circulation and turbulence of the gas within the boat is inhibited. It has been discovered that use of heavy walled iron boats and covers is essential to the production of clean sintered bearings free from any evidence of contamination. It has also been found that thin walled boats and covers are not as effective as those making use of heavier metal, for the temperature gradients in the furnace cannot be absorbed to prevent dumbbell distortion in the bearings.
  • the retort is water quenched. While sintering has been disclosed as carried out in a dry hydrogen atmosphere, nitrogen or any inert gas as well as vacuo can be used for sintering.
  • the surface disclosed herein is for purposes of illustration, and other furnace arrangements are feasible, such as pot-types, as long as the principles disclosed above are maintained.
  • Table III demonstrates the diiference in results between using 0 type coarse copper and a finer copper hereinafter referred to as 90 type (.1% of +100, 5% of 100+150, 4.0% max. of -150+200, 1.5% max. of 200+250, 2-7% -250+325, min. of 325 mesh). In both cases the percentage of copper in the mixture was 2% by weight relative to the aluminum.
  • a continuous belt furnace may be used in conjunction with boats or trays for the bearings,
  • FIGURE 6 summarizes my results on sintering in a schematic representation of the pertinent corner of the Aluminum-Copper phase diagram at temperature ranging from the eutectic up to the melting point of the major alloying element, aluminum.
  • Area B on the diagram defines the optimum range of temperature and composition which is requisite to producing Al-Cu bearings or other porous structures having excellent strength and dimensional control. It is noted that for lower percentages of copper in this range the allowable sintering temperature range increases upward. This is significant, in that, at the higher temperatures, approaching the solidus, for these compositions the sintering time can be reduced considerably Without a loss in crash strength. This results in more economical production of parts.
  • FIGS. 7 and 8 indicate the desirability of using coarse copper powders.
  • FIG. 7 indicates that when copper content and particle size are properly chosen, a plateau in the curve results which allows for dimensional control over a range of temperatures below the solidus. Note that for 2% copper, the final compact size is slightly expanded, which has been found to be ideal for subsequent coining operations.
  • the rate of hornogenization-equilibrium by diffusion-during sintering of mixed powders depends on the particle sizes, which determine the distances between maximum and minimum concentrations. With a given mixture the most rapid homogenization occurs when the particles of the minor constituent have the smaller size.
  • the minor component of a binary system will become more quickly alloyed than the main constituent, the diffusion layers forming envelopes about the particles of the minor component.
  • FIGURES 9 and 10 are a comparison of the pore structure obtained with the coarse and fine types or" copper powders. It is apparent that coarse pores are randomly distributed throughout the structure when coarse copper powders are utilized. It has been explained in the discussion of the sintering mechanism that fine copper powder additions lead to densification and finer pore sizes. Coarse, randomly distributed holes are beneficial to the operation of bearings in that the coarse pores provide wells for storage of oil which can be fed to the fine capillaries formed by the finer particles. In addition, this type of structure has the advantage that the large holes on the surface are more difiicult to close by burnishing or wear, which provides more continuous lubrication properties and a greater factor of safety in operation and in changing bearings.
  • impregnation can take place prior to or following the coining operation.
  • impregnation prior to coining results in very uniform dimensions after coining.
  • the oil acts as a hydrodynamic pressure equalizer which results in more uniform application of coining pressure.
  • dip impregnation is unsatisfactory in that considerable length variations result after coining.
  • end porosity tends to close up in coining dip impregnated samples.
  • vacuum impregnation has become a standard operation. it is also 9 possible to impregnate the pores with lead to prevent burn out of the bearing should the oil be exhausted.
  • Element or alloy added Weight percent added a crush strength of 11,310 p.s.i. and deflection of 9.89%.
  • Po'rousstructural parts can be produced by using an aging treatment following the sintering operation.
  • an aluminum sample containing 4% copper was sintered to a density of 86.3%, having a crush strength of 30,300 p.s.i. and a deflection of 12.1%.
  • Heat treating at 500 C. for 1% hours, followed by water quenching and then vacuum heat treating at 150 C. for 2 to 89 hours results in strengths up to 35,700 p.s.i. with deflections of 4.1%.
  • mixed elemental powders can be loaded into boats, levelled off and sintered to high strengths without prior compacting.
  • the result was a porous, high strength sinter-cake product.
  • Helium or air atomized aluminum can be used. If more "strength or density is required, the cake could then be coined or rolled, cold or hot. These sintercakes can also be impregnated with lead.
  • the sintercake can be consolidated into full density structural parts by hot or cold rolling 'or extrusion. Such parts can also be heat treated and aged to develop requisite structural properties.
  • a tobacco smoke filter may be constructed by forming a highly porous plug of aluminum alloy fabricated in the manner described above.
  • the green compact may be very lightly compacted to produce a high degree of porosity, the sintered product having interconnected parts permitting the flow of smoke therethrough.
  • the plug may be inserted in a cigarette holder or in the stem of a pipe.
  • the filter may also be in the form of a small wafer inserted in the tip of a cigarette, the tip being of the type conventionally now in use With fibrous filters.
  • the advantages of aluminum smoke filters are that by reason of their high conductivity, they act to cool the smoke, to condense harmful nicotine-containing vapours and to filter out smoke and tobacco particles. On the other hand the filter will not affect the taste or odor of the tobacco smoke.
  • a filter of this form is of negligible weight and may readily be inserted in a cigarette tip.
  • Point 1 The problem of sintering atmosphere causing contamination of the part. This is accomplished by the use of a protective sintering tray for containing parts in the furnace and by employing an alloying element, such as copper, which forms a low melting constituent (in the early stages of sintering) and acts as a fluxing agent on the surface of the powder. It is also to be noted that the corrosion resistance of the Al-Cu, or other, solid solution formed on the surf-ace of the powders is superior to pure aluminum. Such sintering has been accomplished successfully in various atmospheres, namely, dry hydrogen, nitrogen and vacuum.
  • Point 2 The problem of refractory oxide or other contaminant films on the surface of elemental powders which cannot be reduced at the sintering temperatures employed. This result has been achieved by providing a low melting fiuxing agent as noted in Point (1) above. Also the degree of fl-uxing required can be controlled by the alloying content. For example, if a very pure powder is utilized (e.g., helium atomized aluminum) loss of the constituent for fluxing (e.g., copper) need be added. The purity of the powder, in turn, is controlled by eliminating particle fines (325 mesh). This can be done for both the major and minor alloying constituent.
  • a very pure powder e.g., helium atomized aluminum
  • loss of the constituent for fluxing e.g., copper
  • Point 3 The problem of die wall pickup and seizure in pressing green compacts. This problem is solved by utilizing low compacting pressures, 3 to 7 t.s.i., and by powder particle size control to provide optimum compactibility. Also the successful application of a powder lubricant is very helpful.
  • the use of low compacting pressures creates the possibility that dies might be manufactured from plastic materials. In any event, the use of tool steels is eliminated and cheaper alloys can be used, such as cold rolled steel.
  • Point 4 The problem of using lubricants mixed in with the powders. Approximately 1 to 3% Sterotex mixed with the elemental powders combined with the use of the special sintering tray arrangement in the sintering operation has eliminated discoloration and oxidation of sintered parts.
  • Point 5 The problem of long, costly sintering times encountered in completely solid state sintering below any liquid temperature. Sintering times are shortened to those that are economically feasible by sintering above ill.
  • Point 6 The problem of excessive shrinkage distortion resulting from liquid phase sintering. This problem was eliminated by maintaining the sintering temperature below the solidus temperature. lF/here absolutely necessary to use liquid phase sintering (e.g., for 4% Cu), it is possible to obtain results by careful control of the time cycle, particle size and the quench cycle.
  • Point 7 The problem of controlling dimensions in sintering to obtain proper sizing control. By producing a slightly expanded sintered part, the coin-out of parts has been facilitated in this investigation. This is done by proper selection of copper content, particle size, and sintering conditions such as temperature and time.
  • Point 8 The problem of producing adequate crush strength simultaneously with reliable dimensional control. This is accomplished by using coarse copper powders and maintaining sintering temperature below the solidus for proper length of time.
  • Point 9 The problem of control of pore size and production of randomly distributed coarse pores having a gradation of finer pores. This problem has been overcome by utilization of coarse aluminum powder and add ing the proper percentage of coarse copper powder which maintains the pore size during the sintering operation.
  • Point l The problem of storage of mixed powders. This is facilitated by the use of coarse aluminum and cop per powders, thereby limiting the exposed surface area of particulates.
  • Point 12 The problem of explosion hazards encountered with aluminum powders and various atmospheres. By elimination of fines (-325 mesh) in the powder mixtures particulate surfaces are stabilized so that ignition and/ or explosive tendencies are eliminated.
  • Point 13 The problem of producing non-contaminated sintercakes directly from powders with no precompaction. This can be done by coating the major alloying element particles with the minor alloying elemental powder (e.g., copper coated on aluminum) and sintering at an appropriate temperature and time. Particle size is controlled to develop proper strength and porosity, if required.
  • Point J4 The use of aluminum and its alloys olfers a number of advantages:
  • Coupled with the above points aluminum has the following properties beneficial in bearing applications: excellent corosion resistance, high fatigue strength, high compression yield strength, good embedability, good conformability, wear resistance, good antiseizure characteristics, high thermal conductivity and low cost.
  • Coarse pores in the bearing are beneficial for the storage of oil which can be fed to the line capillaries. Also this type of structure can be sized readily by various processes (e.g., burnishing) without danger of sealing off the oil supply.
  • Metallic e.g., magnesium
  • non-metallic e.g., Sterotex
  • the method of forming a porous sintered aluminum structure substantially free of contamination and distortion comprising forming a powdered metal mixture Whose metallic components consist essentially of particulate aluminum, from 1 %to 5% by weight of particulate copper, shaping the mixture and heating the shaped mixture to a sintering temperature above the eutectic temperature but below the solidus temperature for the particular composition, the rate of heating being such that a copper-aluminum liquid phase is formed which thereafter solidifies as equilibrium conditions are achieved, thereby bringing all increments of the mixture above the eutectic composition and below the solidus level, and maintaining the sintering temperature for the period of time necessary to achieve sintering, the heating being carried out in an atmosphere, selected from the group consisting of inert gases and hydrogen, whose dew point is at least as dry as F., any compaction of the mixture being carried out prior to heating.
  • a porous siutered aluminous bearing substantially free of contamination and distortion comprising forming a powdered metal mixture whose metallic components consist essentially of particulate aluminum with from 1%% to 2%% by weight of particulate copper, said mixture also including an organic lubricant in an amount up to 3% by weight, shaping said mixture with an applied pressure not exceeding 7 t.s.i.
  • a green compact having the general shape of the required bearing, heating said green compact to a sintering temperature above the eutectic temperature but below the solidus temperature for the particular composition, the rate of heating being such that a copper-aluminum liquid phase is formed which thereafter solidifies as equilibrium conditions are achieved, thereby bringing all increments of the mixture below the eutectic composition and below the solidus level at the particular temperature, and maintaining the sintering temperature for the period of time necessary to achieve sintering, the heating being carried out in an atmosphere, selected from the group consisting of inert gases and hydrogen, whose dew point is at least as dry as -80 F., any compaction of the mixture being carried out prior to heating.
US150826A 1961-11-07 1961-11-07 Porous metallic bodies and fabrication methods therefor Expired - Lifetime US3232754A (en)

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US150826A US3232754A (en) 1961-11-07 1961-11-07 Porous metallic bodies and fabrication methods therefor
CH1297162A CH447620A (fr) 1961-11-07 1962-11-06 Procédé pour fabriquer une structure frittée
GB41959/62A GB1015491A (en) 1961-11-07 1962-11-06 Improvements in or relating to porous metallic bodies and fabrication methods therefor
DE1962A0041565 DE1458315B2 (de) 1961-11-07 1962-11-07 Verfahren zur Herstellung poröser, gesinterter Formkörper aus einer Al-Cu-Legierung

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3326676A (en) * 1965-05-05 1967-06-20 Deventer Werke G M B H Method of producing coherent bodies of metallic particles
US3359095A (en) * 1964-02-19 1967-12-19 Dow Chemical Co Sintering of loose particulate aluminum metal
US3366479A (en) * 1965-04-28 1968-01-30 Alloys Res & Mfg Corp Powder metallurgy
US3506438A (en) * 1967-07-24 1970-04-14 Mallory & Co Inc P R Method of producing beryllium composites by liquid phase sintering
EP0180010A2 (fr) * 1984-10-26 1986-05-07 International Business Machines Corporation Traitement de matériaux dans des fours
DE4034637A1 (de) * 1989-10-31 1991-05-02 Eckart Standard Bronzepulver Verfahren zur herstellung von poroesen al-werkstoffen
US5788737A (en) * 1995-05-31 1998-08-04 N.D.C. Co., Ltd. Aluminum base sintered material
EP0900610A1 (fr) * 1997-09-05 1999-03-10 Maxon-Motor GmbH Procédé de préparation de palier en métal fritté pour arbre céramique ainsi que palier obtenu
WO2002000377A1 (fr) * 2000-06-28 2002-01-03 Eisenmann Maschinenbau Kg Procede et dispositif pour le frittage de pieces frittees a base d'aluminium
US20100221136A1 (en) * 2009-01-30 2010-09-02 Maffia Gennaro J Porous Metallic Structures

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US5248475A (en) * 1991-10-24 1993-09-28 Derafe, Ltd. Methods for alloy migration sintering
CN113245543B (zh) * 2021-07-15 2021-10-01 江苏集萃先进金属材料研究所有限公司 一种铜粉及其制备方法和用该铜粉制得的毛细芯

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US2155651A (en) * 1937-06-17 1939-04-25 Hardy Metallurg Corp Manufacture of aluminum alloys
US2241095A (en) * 1940-02-01 1941-05-06 Gen Motors Corp Method of making porous metal structures
US2287251A (en) * 1939-07-07 1942-06-23 Jones William David Manufacture of nonporous metal articles
US2746741A (en) * 1954-01-27 1956-05-22 Mannesmann Ag Apparatus for the production of wrought metal shapes from metal powder
US2746742A (en) * 1949-03-24 1956-05-22 Int Nickel Co Apparatus for producing porous metal plates
US2994606A (en) * 1958-12-03 1961-08-01 Gen Motors Corp Method of manufacturing sintered bearings
US3007794A (en) * 1957-08-15 1961-11-07 Birmingham Small Arms Co Ltd Production of ducted articles

Patent Citations (7)

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Publication number Priority date Publication date Assignee Title
US2155651A (en) * 1937-06-17 1939-04-25 Hardy Metallurg Corp Manufacture of aluminum alloys
US2287251A (en) * 1939-07-07 1942-06-23 Jones William David Manufacture of nonporous metal articles
US2241095A (en) * 1940-02-01 1941-05-06 Gen Motors Corp Method of making porous metal structures
US2746742A (en) * 1949-03-24 1956-05-22 Int Nickel Co Apparatus for producing porous metal plates
US2746741A (en) * 1954-01-27 1956-05-22 Mannesmann Ag Apparatus for the production of wrought metal shapes from metal powder
US3007794A (en) * 1957-08-15 1961-11-07 Birmingham Small Arms Co Ltd Production of ducted articles
US2994606A (en) * 1958-12-03 1961-08-01 Gen Motors Corp Method of manufacturing sintered bearings

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3359095A (en) * 1964-02-19 1967-12-19 Dow Chemical Co Sintering of loose particulate aluminum metal
US3366479A (en) * 1965-04-28 1968-01-30 Alloys Res & Mfg Corp Powder metallurgy
US3326676A (en) * 1965-05-05 1967-06-20 Deventer Werke G M B H Method of producing coherent bodies of metallic particles
US3506438A (en) * 1967-07-24 1970-04-14 Mallory & Co Inc P R Method of producing beryllium composites by liquid phase sintering
EP0180010A2 (fr) * 1984-10-26 1986-05-07 International Business Machines Corporation Traitement de matériaux dans des fours
EP0180010A3 (fr) * 1984-10-26 1988-08-10 International Business Machines Corporation Traitement de matériaux dans des fours
DE4034637A1 (de) * 1989-10-31 1991-05-02 Eckart Standard Bronzepulver Verfahren zur herstellung von poroesen al-werkstoffen
US5788737A (en) * 1995-05-31 1998-08-04 N.D.C. Co., Ltd. Aluminum base sintered material
EP0900610A1 (fr) * 1997-09-05 1999-03-10 Maxon-Motor GmbH Procédé de préparation de palier en métal fritté pour arbre céramique ainsi que palier obtenu
US6174087B1 (en) 1997-09-05 2001-01-16 Maxon Motor Gmbh Friction bearing
US6223437B1 (en) 1997-09-05 2001-05-01 Maxon Motor Gmbh Method for fabricating a friction bearing, and friction bearing
WO2002000377A1 (fr) * 2000-06-28 2002-01-03 Eisenmann Maschinenbau Kg Procede et dispositif pour le frittage de pieces frittees a base d'aluminium
US20030143098A1 (en) * 2000-06-28 2003-07-31 Hartmut Weber Method and device for sintering aluminum based sintered parts
US6821478B2 (en) 2000-06-28 2004-11-23 Eisenmann Maschinenbau Kg Method and device for sintering aluminum based sintered parts
US20100221136A1 (en) * 2009-01-30 2010-09-02 Maffia Gennaro J Porous Metallic Structures
US8329091B2 (en) * 2009-01-30 2012-12-11 Widener University Porous metallic structures
US20130171466A1 (en) * 2009-01-30 2013-07-04 Gennaro J. Maffia Porous metallic structures

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DE1458315A1 (fr) 1968-10-17
GB1015491A (en) 1966-01-05
CH447620A (fr) 1967-11-30
DE1458315B2 (de) 1970-06-11

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