EP0319786B1 - Process for preparing secondary powder particles with a nanocrystalline structure and with a closed surface - Google Patents
Process for preparing secondary powder particles with a nanocrystalline structure and with a closed surface Download PDFInfo
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- EP0319786B1 EP0319786B1 EP88119570A EP88119570A EP0319786B1 EP 0319786 B1 EP0319786 B1 EP 0319786B1 EP 88119570 A EP88119570 A EP 88119570A EP 88119570 A EP88119570 A EP 88119570A EP 0319786 B1 EP0319786 B1 EP 0319786B1
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- 239000000843 powder Substances 0.000 title claims description 42
- 239000002245 particle Substances 0.000 title claims description 17
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 239000000203 mixture Substances 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 13
- 239000013078 crystal Substances 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 230000005540 biological transmission Effects 0.000 claims description 4
- 238000010587 phase diagram Methods 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 229910052735 hafnium Inorganic materials 0.000 claims description 3
- 229910052748 manganese Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 3
- 150000004767 nitrides Chemical class 0.000 claims description 3
- 229910052763 palladium Inorganic materials 0.000 claims description 3
- 229910052715 tantalum Inorganic materials 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 229910052720 vanadium Inorganic materials 0.000 claims description 3
- 229910052727 yttrium Inorganic materials 0.000 claims description 3
- 229910052726 zirconium Inorganic materials 0.000 claims description 3
- -1 borides Chemical class 0.000 claims description 2
- 229910010293 ceramic material Inorganic materials 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 239000000470 constituent Substances 0.000 claims description 2
- 150000001247 metal acetylides Chemical class 0.000 claims description 2
- 238000010316 high energy milling Methods 0.000 claims 1
- 150000002739 metals Chemical class 0.000 claims 1
- 238000000227 grinding Methods 0.000 description 14
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 7
- 239000000126 substance Substances 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000007787 solid Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000004438 BET method Methods 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 238000003917 TEM image Methods 0.000 description 1
- HZEWFHLRYVTOIW-UHFFFAOYSA-N [Ti].[Ni] Chemical compound [Ti].[Ni] HZEWFHLRYVTOIW-UHFFFAOYSA-N 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
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- 239000002356 single layer Substances 0.000 description 1
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Images
Classifications
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- 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
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
-
- 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
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/002—Making metallic powder or suspensions thereof amorphous or microcrystalline
- B22F9/004—Making metallic powder or suspensions thereof amorphous or microcrystalline by diffusion, e.g. solid state reaction
- B22F9/005—Transformation into amorphous state by milling
-
- 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
Definitions
- the invention relates to a method for producing secondary powder particles with a nanocrystalline structure and with a sealed particle surface.
- Materials with a nanocrystalline structure can be produced in such a way that crystals with a diameter of a few nanometers are compacted into a solid under high pressure (a few MPa). Basically, all methods of powder production are suitable with which sufficiently small crystals with a "clean" surface can be realized.
- the problem is solved for powder mixtures whose composition tends to set amorphous structure, surprisingly by exposing the starting powder to high mechanical stress of at least 12 g at room temperature under neutral or reducing atmosphere over a longer period of time.
- the composition is chosen such that, according to the corresponding metastable phase diagram, a multiphase region between the amorphous and crystalline phase is present in the secondary powder to be produced at a suitable temperature at this composition.
- the duration for the production of the secondary powder is determined according to transmission electro-microscopic recordings (TEM); The desired final state is only achieved if these only have crystallites with a diameter of ⁇ 10 nm.
- the starting powders are subjected to a grinding process, excessive heating must be avoided, since otherwise the metastable amorphous phase will not be preserved; so that the desired nanocrystalline structure forms, on the other hand, the grinding process must not be too slow.
- the process can be carried out in particular using commercially available starting powders with a particle size between 2 and 250 ⁇ m.
- the starting powder can consist of metallic materials, of materials with a metal character and of ceramic materials with several components.
- the process can also be carried out using binary or multiphase substances which consist of at least one element from the group Y, Ti, Zr, Hf, Nb, Mo, Ta, W with at least one element from the group V, Cr, Mn, Fe, Co, Ni, Cu, Pd and optionally at least one accompanying element such as Si, Ge, B and / or oxides, nitrides, borides, carbides and their possible mixed crystals exist, the selected constituents in pure form or as master alloys in the manner mentioned above are mixed as a powder (claim 2 or 3).
- the required high mechanical stress can be caused by cold working or by high-energy grinding (claim 4 or 5), the latter for example by impact grinding, especially in an attritor.
- the specific surface area of the secondary powder particles produced according to the invention does not increase with the milling time, but remains the same size or decreases slightly, ie the sealing is gas-tight and there are no inner surfaces in the area of the nanocrystalline structural components which are accessible to the gases of the surrounding atmosphere.
- the surfaces in the nanocrystalline area remain "clean"; the chemical resistance is unexpectedly high because the small crystallites are embedded in an amorphous phase.
- the powder mixture used consists of 70% by weight of commercially available Ti powder (FSSS: 28 ⁇ m) and 30% by weight of commercially available Ni powder (FSSS: 4.7 ⁇ m).
- the two powders are first mixed over a period of one hour in a (Turbula) mixer and then ground in a horizontally lying attritor; the powder batch weight is 1000 g. Grinding is carried out at an agitator arm speed of 200 rpm. over a period of 90 hours using rolling bearing balls with a diameter of approximately 6 mm and a mass ratio between balls and powder mixture of 20: 1.
- the time required for the grinding process can be significantly reduced by using larger grinding units (batch use: 10 kg).
- the measurement of the specific surface of a Ti / Ni powder mixture with 70/30 mass% according to the BET method gives the following values (depending on the grinding time): 0.152 m2 / g (0 h) or 0.140 m2 / g (90 h) or 0.137 m2 / g (180 h): The surprisingly, the specific surface decreases slightly with the grinding time.
- FIG. 2a to 2c show the results of experiments in which 50 mg of the Ti / Ni powder with 70/30 mass% have been introduced into a 1N HNO3 solution, at 30 ° C (Fig. 2a) or 40 ° C (Fig. 2b) or 50 ° C (Fig. 2c).
- the detached amount of Ni is shown as a function of time for powders obtained with different grinding times; These were first mixed in the Turbula mixer over a period of one hour and then ground in the attritor for 0 h - 180 h.
- the diagrams in question show that the amount of Ni removed takes on significantly lower values as the grinding time increases. After a grinding time of 36 hours, the secondary powder produced shows a considerably higher chemical resistance than the untreated starting powder mixture.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Crystallography & Structural Chemistry (AREA)
- Powder Metallurgy (AREA)
- Carbon And Carbon Compounds (AREA)
- Oxygen, Ozone, And Oxides In General (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
Description
Die Erfindung betrifft ein Verfahren zur Herstellung von Sekundärpulverteilchen mit nanokristalliner Struktur und mit versiegelter Teilchenoberfläche.The invention relates to a method for producing secondary powder particles with a nanocrystalline structure and with a sealed particle surface.
Werkstoffe mit nanokristalliner Struktur lassen sich in der Weise erzeugen, daß Kristalle mit einem Durchmesser von einigen Nanometern unter hohem Druck (einige MPa) zu einem Festkörper kompaktiert werden. Grundsätzlich sind alle Methoden der Pulverherstellung geeignet, mit denen sich hinreichend kleine Kristalle mit "sauberer" Oberfläche verwirklichen lassen.Materials with a nanocrystalline structure can be produced in such a way that crystals with a diameter of a few nanometers are compacted into a solid under high pressure (a few MPa). Basically, all methods of powder production are suitable with which sufficiently small crystals with a "clean" surface can be realized.
Bei der Herstellung kleiner Kristallite ist zwischen chemischen und physikalischen Verfahren zu unterscheiden.
Bei den chemischen Verfahren handelt es sich vorrangig um die thermische Zersetzung fester bzw. gasförmiger Verbindungen sowie um die Reduktion fester Substanzen bzw. von Metallionen in Lösungen. Ein wesentlicher Nachteil vieler derartiger Verfahren ist die Belegung der freien Oberfläche der Kristallite mit Fremdatomen bzw. Fremdmolekülen.
Zu den bekannten physikalischen Verfahren, welche zur Herstellung kleiner Kristalle am häufigsten angewendet werden, zählen das Zerstäuben im elektrischen Lichtbogen und das Verdampfen in einer inerten Atmosphäre bzw. im Vakuum mit nachfolgender isoentroper Entspannung. Diese Verfahren weisen den Vorteil auf, daß die Oberfläche des erhaltenen einzelnen Kristallpulverteilchens bei geeigneter Verfahrensführung von Fremdstoffen praktisch freigehalten werden kann und daß das Pulver direkt zu Formkörpern mit nanokristalliner Struktur kompaktierbar ist. Da zur Erzeugung beispielsweise einer Monolage Sauerstoff auf der freien Oberfläche von 1 g Eisenkristalliten mit einem Durchmesser von 5 nm nur etwa 0,1 g Sauerstoff erforderlich ist und da diese Menge etwa 10¹⁰ mal mehr Sauerstoff darstellt, als typischerweise im Restgas eines Vakuumrezipienten enthalten ist, dauert es nicht lange, bis sich auf der großen spezifischen Oberfläche der hier beispielhaft angeführten Eisenpartikel im Nanometer-Bereich relativ große Mengen an unerwünschtem Sauerstoff, Stickstoff und/oder Wassermolekülen angelagert haben, um dort beispielsweise Oxid-, Nitrid- und/oder Oxinitrid-Beläge auszubilden. Auch in diesem Fall muß also ein erheblicher Aufwand betrieben werden, um zum Zwecke der Herstellung sauberer Werkstoffe mit nanokristalliner Struktur die Bildung von Verunreinigungen an den Kristallitoberflächen zu vermeiden.A distinction must be made between chemical and physical processes in the manufacture of small crystallites.
The chemical processes primarily involve the thermal decomposition of solid or gaseous compounds and the reduction of solid substances or metal ions in solutions. A major disadvantage of many such The method is to cover the free surface of the crystallites with foreign atoms or foreign molecules.
Known physical processes, which are used most frequently for the production of small crystals, include sputtering in an electric arc and evaporation in an inert atmosphere or in vacuo with subsequent iso-entropic relaxation. These processes have the advantage that the surface of the individual crystal powder particle obtained can be kept practically free of foreign substances if the process is carried out in a suitable manner and that the powder can be compacted directly into shaped bodies with a nanocrystalline structure. Since only about 0.1 g of oxygen is required to generate, for example, a monolayer of oxygen on the free surface of 1 g of iron crystallites with a diameter of 5 nm, and since this amount represents about 10¹⁰ times more oxygen than is typically contained in the residual gas of a vacuum recipient, it does not take long for relatively large amounts of undesirable oxygen, nitrogen and / or water molecules to have accumulated on the large specific surface area of the iron particles exemplified here, for example to cover oxide, nitride and / or oxynitride deposits to train. In this case too, considerable effort must be expended in order to avoid the formation of impurities on the crystallite surfaces for the purpose of producing clean materials with a nanocrystalline structure.
Es ist daher Aufgabe der Erfindung, den geschilderten Nachteil dadurch zu umgehen, daß Sekundärpulverteilchen im Bereich von einigen Mikrometern mit nanokristalliner Struktur erzeugt werden, die auf ihrer äußeren Oberfläche gegenüber den möglichen Komponenten des Umgebungungsmediums gasdicht versiegelt und somit unter den üblichen Bedingungen einer pulvermetallurgischen Fertigung problemlos zu Formkörpern mit nanokristalliner Struktur verarbeitbar sind.It is therefore an object of the invention to circumvent the described disadvantage in that secondary powder particles in the range of a few micrometers with a nanocrystalline structure are produced which face each other on their outer surface the possible components of the surrounding medium are sealed in a gas-tight manner and can therefore be processed without problems under the usual conditions of powder metallurgy production to give moldings with a nanocrystalline structure.
Die Lösung der Aufgabe gelingt für Pulvermischungen, die in ihrer Zusammensetzung zur Einstellung amorpher Gefügeanteile neigen, überraschenderweise dadurch, daß man die Ausgangspulver bei Raumtemperatur unter neutraler bzw. reduzierender Atmosphäre über eine längere Zeitdauer einer hohen mechanischen Beanspruchung von mindestens 12 g aussetzt. Die Zusammensetzung wird dabei derart gewählt, daß nach dem entsprechenden metastabilen Phasendiagramm in dem zu erzeugenden Sekundärpulver bei geeigneter Temperatur bei dieser Zusammensetzung ein Mehrphasengebiet zwischen amorpher und kristalliner Phase vorliegt. Die Dauer zur Herstellung des Sekundärpulvers wird bestimmt nach transmissions-elektromikroskopischen Aufnahmen (TEM); erst wenn diese nur Kristallite mit einem Durchmesser < als 10 nm aufweisen, ist der angestrebte Endzustand erreicht.The problem is solved for powder mixtures whose composition tends to set amorphous structure, surprisingly by exposing the starting powder to high mechanical stress of at least 12 g at room temperature under neutral or reducing atmosphere over a longer period of time. The composition is chosen such that, according to the corresponding metastable phase diagram, a multiphase region between the amorphous and crystalline phase is present in the secondary powder to be produced at a suitable temperature at this composition. The duration for the production of the secondary powder is determined according to transmission electro-microscopic recordings (TEM); The desired final state is only achieved if these only have crystallites with a diameter of <10 nm.
Falls die Ausgangspulver einem Mahlvorgang unterworfen werden, muß eine starke Erwärmung vermieden werden, da sonst die metastabile amorphe Phase nicht erhalten bleibt; damit sich die gewünschte nanokristalline Struktur ausbildet, darf der Mahlvorgang andererseits auch nicht zu langsam ablaufen.If the starting powders are subjected to a grinding process, excessive heating must be avoided, since otherwise the metastable amorphous phase will not be preserved; so that the desired nanocrystalline structure forms, on the other hand, the grinding process must not be too slow.
Das Verfahren läßt sich insbesondere unter Verwendung handelsüblicher Ausgangspulver mit einer Teilchengröße zwischen 2 und 250 µm ausführen.The process can be carried out in particular using commercially available starting powders with a particle size between 2 and 250 μm.
Gemäß Anspruch 1 kann das Ausgangspulver aus metallischen Werkstoffen, aus Werkstoffen mit Metallcharakter und aus keramischen Werkstoffen mit mehreren Komponenten bestehen.
Das Verfahren läßt sich jedoch auch unter Verwendung binärer oder mehrphasiger Stoffe ausführen, die aus mindestens einem Element der Gruppe Y, Ti, Zr, Hf, Nb, Mo, Ta, W mit mindestens einem Element der Gruppe V, Cr, Mn, Fe, Co, Ni, Cu, Pd sowie ggf. mindestens einem Begleitelement wie Si, Ge, B und/oder Oxiden, Nitriden, Boriden, Carbiden sowie deren möglichen Mischkristallen bestehen, wobei die ausgewählten Bestandteile in reiner Form oder als Vorlegierungen in der zuvor erwähnten Weise als Pulver gemischt werden (Anspruch 2 bzw. 3).According to claim 1, the starting powder can consist of metallic materials, of materials with a metal character and of ceramic materials with several components.
However, the process can also be carried out using binary or multiphase substances which consist of at least one element from the group Y, Ti, Zr, Hf, Nb, Mo, Ta, W with at least one element from the group V, Cr, Mn, Fe, Co, Ni, Cu, Pd and optionally at least one accompanying element such as Si, Ge, B and / or oxides, nitrides, borides, carbides and their possible mixed crystals exist, the selected constituents in pure form or as master alloys in the manner mentioned above are mixed as a powder (claim 2 or 3).
Die erforderliche hohe mechanische Beanspruchung kann durch Kaltverformen oder durch Hochenergiemahlen hervorgerufen werden (Anspruch 4 bzw. 5), letzteres beispielsweise durch Impact-Grinding insbesondere in einem Attritor.The required high mechanical stress can be caused by cold working or by high-energy grinding (claim 4 or 5), the latter for example by impact grinding, especially in an attritor.
Überraschenderweise nimmt die spezifische Oberfläche der erfindungsgemäß hergestellten Sekundärpulverteilchen mit der Mahldauer nicht zu, sondern bleibt gleich groß oder nimmt geringfügig ab, d. h. die Versiegelung ist gasdicht und im Bereich der nanokristallinen Gefügeanteile liegen keine inneren Oberflächen vor, welche den Gasen der umgebenden Atmosphäre zugänglich sind. Die Oberflächen im nanokristallinen Bereich bleiben "sauber"; die chemische Resistenz ist unerwartet hoch, da die kleinen Kristallite in einer amorphen Phase eingebettet sind.Surprisingly, the specific surface area of the secondary powder particles produced according to the invention does not increase with the milling time, but remains the same size or decreases slightly, ie the sealing is gas-tight and there are no inner surfaces in the area of the nanocrystalline structural components which are accessible to the gases of the surrounding atmosphere. The surfaces in the nanocrystalline area remain "clean"; the chemical resistance is unexpectedly high because the small crystallites are embedded in an amorphous phase.
Die Erfindung wird nachfolgend am Beispiel einer Titan-Nickel-Pulvermischung als Ausgangspulver erläutert.The invention is explained below using the example of a titanium-nickel powder mixture as the starting powder.
Die zum Einsatz kommende Pulvermischung besteht zu 70 Gew.-% aus handelsüblichem Ti-Pulver (FSSS:28 µm) und zu 30 Gew.-% aus handelsüblichem Ni-Pulver (FSSS:4,7 µm). Die beiden Pulver werden zunächst über einen Zeitraum von einer Stunde in einem (Turbula)-Mischer gemischt und anschließend in einem horizontal liegenden Attritor gemahlen; das Pulverchargengewicht beträgt 1000 g. Die Mahlung erfolgt bei einer Rührarmdrehzahl von 200 U/min. über einen Zeitraum von 90 Stunden unter Verwendung von Wälzlagerkugeln mit einem Durchmesser von etwa 6 mm und einem Massenverhältnis zwischen Kugeln und Pulvermischung von 20:1.
Durch Einsatz größerer Mahlaggregate (Chargeneinsatz: 10 kg) kann die für den Mahlvorgang benötigte Zeitspanne signifikant gesenkt werden.The powder mixture used consists of 70% by weight of commercially available Ti powder (FSSS: 28 µm) and 30% by weight of commercially available Ni powder (FSSS: 4.7 µm). The two powders are first mixed over a period of one hour in a (Turbula) mixer and then ground in a horizontally lying attritor; the powder batch weight is 1000 g. Grinding is carried out at an agitator arm speed of 200 rpm. over a period of 90 hours using rolling bearing balls with a diameter of approximately 6 mm and a mass ratio between balls and powder mixture of 20: 1.
The time required for the grinding process can be significantly reduced by using larger grinding units (batch use: 10 kg).
Fig. 1 zeigt für ein Ti/Ni-Sekundärpulver mit 70/30 Massen-% eine TEM-Aufnahme mit einer Vergrößerung von 200.000:1 nach einer Mahldauer von 40 Stunden. Deutlich erkennbar ist die Einbettung von Kristalliten, die jedoch teilweise noch eine Größe von mehr als 10 nm aufweisen, in einer bereits vorhandenen amorphen Phase.
Nach einer Mahldauer von 90 Stunden sind in der amorphen Phase nur noch Kristallite mit einer Größe von < 10 nm feststellbar.1 shows a TEM image with a magnification of 200,000: 1 after a grinding time of 40 hours for a Ti / Ni secondary powder with 70/30 mass%. The embedding of crystallites, some of which, however, still have a size of more than 10 nm, is clearly recognizable in an already existing amorphous phase.
After a grinding time of 90 hours, only crystallites with a size of <10 nm can be found in the amorphous phase.
Die Messung der spezifischen Oberfläche einer Ti/Ni-Pulvermischung mit 70/30 Massen-% nach dem BET-Verfahren ergibt (in Abhängigkeit von der Mahldauer) folgende Werte: 0,152 m²/g (0 h) bzw. 0,140 m²/g (90 h) bzw. 0,137 m²/g (180 h): Die spezifische Oberfläche nimmt also überraschenderweise mit der Mahldauer geringfügig ab.The measurement of the specific surface of a Ti / Ni powder mixture with 70/30 mass% according to the BET method gives the following values (depending on the grinding time): 0.152 m² / g (0 h) or 0.140 m² / g (90 h) or 0.137 m² / g (180 h): The surprisingly, the specific surface decreases slightly with the grinding time.
Die Fig. 2a bis 2c zeigen die Ergebnisse von Versuchen, bei denen jeweils 50 mg des Ti/Ni-Pulvers mit 70/30 Massen-% in eine 1 n HNO₃-Lösung eingebracht worden sind, und zwar bei 30°C (Fig. 2a) bzw. 40°C (Fig. 2b) bzw. 50°C (Fig. 2c). Dargestellt ist die abgelöste Ni-Menge in Abhängigkeit von der Zeit für mit unterschiedlicher Mahldauer gewonnene Pulver; diese sind jeweils zunächst über einen Zeitraum von einer Stunde im Turbula-Mischer gemischt und anschließend 0 h - 180 h lang im Attritor gemahlen worden. Die in Rede stehenden Darstellungen lassen erkennen, daß die abgelöste Ni-Menge mit länger werdender Mahldauer wesentlich niedrigere Werte annimmt.
Das hergestellte Sekundärpulver zeigt bereits nach einer Mahldauer von 36 Stunden eine beachtlich höhere chemische Resistenz als die unbehandelte Ausgangspulver-Mischung.2a to 2c show the results of experiments in which 50 mg of the Ti / Ni powder with 70/30 mass% have been introduced into a 1N HNO₃ solution, at 30 ° C (Fig. 2a) or 40 ° C (Fig. 2b) or 50 ° C (Fig. 2c). The detached amount of Ni is shown as a function of time for powders obtained with different grinding times; These were first mixed in the Turbula mixer over a period of one hour and then ground in the attritor for 0 h - 180 h. The diagrams in question show that the amount of Ni removed takes on significantly lower values as the grinding time increases.
After a grinding time of 36 hours, the secondary powder produced shows a considerably higher chemical resistance than the untreated starting powder mixture.
Claims (5)
- Process for preparing secondary powder particles with a nanocrystalline structure and with a closed particle surface, from powders of at least two materials of the groups of metals, of compounds with metal character, and ceramic materials, in a composition which tends towards the regulation of amorphous structure content, whereby the powder is mixed in such a manner that, according to the corresponding metastable phase diagram, in the secondary powder to be produced at a suitable temperature from this composition, exists a multiphase region between amorphous and crystalline phase, and whilst the mixture is subjected to a high mechanical stress of at least 12 g until secondary powder particles in the region of a few micrometers with crystallites are produced, which are detected by electron microscopic transmission to have a diameter of < 10 nm only.
- Process for preparing secondary powder particles with a nanocrystalline structure and with a closed particle surface, from binary or multi-phase materials, which consist of at least one of the elements Y, Ti, Zr, Hf, Nb, Mo, Ta, and W with at least one of the elements V, Cr, Mn, Fe, Co, Ni, Cu and Pd, in a composition which tends towards the regulation of amorphous structure content, whereby the selected elements in pure form or as pre-blends are mixed as a powder in such a manner that, according to the corresponding metastable phase diagram, in the secondary powder to be produced at a suitable temperature from this composition, exists a multiphase region between amorphous and crystalline phase, and whilst the mixture is subjected to a high mechanical stress of at least 12 g, until secondary powder particles in the region of a few micrometers with crystallites are produced, which are detected by electron microscopic transmission to have a diameter of < 10 nm only.
- Process for preparing secondary powder particles with a nanocrystalline structure and with a closed particle surface, from binary or multi-phase materials, which. consist of at least one of the elements Y, Ti, Zr, Hf, Nb, Mo, Ta and W with at least one of the elements V, Cr, Mn, Fe, Co, Ni, Cu and Pd and at least one accompanying element such as Si, Ge, B and/or oxides, nitrides, borides, carbides, as well as their possible mixed crystals, in a composition which tends towards the regulation of amorphous structure, whereby the selected constituents in pure form or as pre-blends are mixed as a powder in such a manner that, according to the corresponding metastable phase diagram, in the secondary powder to be produced at a suitable temperature from this composition, exists a multiphase region between amorphous and crystalline phase, and whilst the mixture is subjected to a high mechanical stress of at least 12 g until secondary powder particles in the region of a few micrometers with crystallites are produced, which are detected by electron microscopic transmission to have a diameter of < 10 nm only.
- Process according to Claims 1 to 3, characterised by the high mechanical stress being created by cold deformation.
- Process according to Claims 1 to 3, characterised by the high mechanical stress being created by high energy milling.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19873741119 DE3741119A1 (en) | 1987-12-04 | 1987-12-04 | PRODUCTION OF SECONDARY POWDER PARTICLES WITH NANOCRISTALLINE STRUCTURE AND WITH SEALED SURFACES |
| DE3741119 | 1987-12-04 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0319786A1 EP0319786A1 (en) | 1989-06-14 |
| EP0319786B1 true EP0319786B1 (en) | 1993-10-27 |
Family
ID=6341878
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP88119570A Expired - Lifetime EP0319786B1 (en) | 1987-12-04 | 1988-11-24 | Process for preparing secondary powder particles with a nanocrystalline structure and with a closed surface |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5149381A (en) |
| EP (1) | EP0319786B1 (en) |
| JP (1) | JPH01208401A (en) |
| CA (1) | CA1320940C (en) |
| DE (1) | DE3741119A1 (en) |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1990007012A1 (en) * | 1988-12-22 | 1990-06-28 | The University Of Western Australia | Process for the production of metals, alloys and ceramic materials |
| EP0406580B1 (en) * | 1989-06-09 | 1996-09-04 | Matsushita Electric Industrial Co., Ltd. | A composite material and a method for producing the same |
| DE4110543A1 (en) * | 1991-03-30 | 1992-10-01 | Pm Hochtemperatur Metall Gmbh | OXIDE DISPERSION HARDENED ELIGIBLE CHROME CHROME ALLOY |
| US5877437A (en) * | 1992-04-29 | 1999-03-02 | Oltrogge; Victor C. | High density projectile |
| JP2892231B2 (en) * | 1992-09-16 | 1999-05-17 | 健 増本 | Ti-Si-N-based composite hard film and method for producing the same |
| US5433797A (en) * | 1992-11-30 | 1995-07-18 | Queen's University | Nanocrystalline metals |
| US5984996A (en) * | 1995-02-15 | 1999-11-16 | The University Of Connecticut | Nanostructured metals, metal carbides, and metal alloys |
| US5589011A (en) * | 1995-02-15 | 1996-12-31 | The University Of Connecticut | Nanostructured steel alloy |
| US6033624A (en) * | 1995-02-15 | 2000-03-07 | The University Of Conneticut | Methods for the manufacturing of nanostructured metals, metal carbides, and metal alloys |
| JP2899682B2 (en) * | 1996-03-22 | 1999-06-02 | 科学技術庁金属材料技術研究所長 | Ti-Ni based shape memory alloy and method for producing the same |
| US5905000A (en) * | 1996-09-03 | 1999-05-18 | Nanomaterials Research Corporation | Nanostructured ion conducting solid electrolytes |
| US6933331B2 (en) | 1998-05-22 | 2005-08-23 | Nanoproducts Corporation | Nanotechnology for drug delivery, contrast agents and biomedical implants |
| JPH10218700A (en) * | 1997-02-07 | 1998-08-18 | Natl Res Inst For Metals | Alloy-based nanocrystal assembly and its production |
| EP1117500B8 (en) * | 1998-09-30 | 2002-10-30 | Hydro-Quebec | Preparation of nanocrystalline alloys by mechanical alloying carried out at elevated temperatures |
| US6600127B1 (en) | 1999-09-15 | 2003-07-29 | Nanotechnologies, Inc. | Method and apparatus for direct electrothermal-physical conversion of ceramic into nanopowder |
| US6472632B1 (en) | 1999-09-15 | 2002-10-29 | Nanoscale Engineering And Technology Corporation | Method and apparatus for direct electrothermal-physical conversion of ceramic into nanopowder |
| US6855426B2 (en) | 2001-08-08 | 2005-02-15 | Nanoproducts Corporation | Methods for producing composite nanoparticles |
| US7708974B2 (en) | 2002-12-10 | 2010-05-04 | Ppg Industries Ohio, Inc. | Tungsten comprising nanomaterials and related nanotechnology |
| US6858173B2 (en) * | 2003-01-30 | 2005-02-22 | The Regents Of The University Of California | Nanocrystalline ceramic materials reinforced with single-wall carbon nanotubes |
| US7556982B2 (en) * | 2003-08-07 | 2009-07-07 | Uchicago Argonne, Llc | Method to grow pure nanocrystalline diamond films at low temperatures and high deposition rates |
| DE102010050771B4 (en) * | 2010-11-10 | 2014-05-08 | Schott Ag | Product of glass or glass-ceramic with high-temperature stable low-energy layer, method of making same and use of the product |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0288785A2 (en) * | 1987-04-29 | 1988-11-02 | Fried. Krupp AG Hoesch-Krupp | Process for preparing a material with a nanocrystalline structure |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3728088A (en) * | 1968-03-01 | 1973-04-17 | Int Nickel Co | Superalloys by powder metallurgy |
| US3591362A (en) * | 1968-03-01 | 1971-07-06 | Int Nickel Co | Composite metal powder |
| GB1298944A (en) * | 1969-08-26 | 1972-12-06 | Int Nickel Ltd | Powder-metallurgical products and the production thereof |
| DE2412022A1 (en) * | 1974-03-13 | 1975-09-25 | Krupp Gmbh | Heat resistant, dispersion hardened, temperable alloys - made by milling powdered base metal, dispersate, and oxygen-refined metal in milling fluid |
| JPS5823457B2 (en) * | 1977-08-11 | 1983-05-16 | 三菱マテリアル株式会社 | Tough cermet |
| DE2855693A1 (en) * | 1978-12-22 | 1980-06-26 | Kennametal Inc | Titanium di:boride and niobium nitride mixed with binder metal - then pressed into compacts subjected to two sintering operations to mfr. very hard tools etc. |
| US4557893A (en) * | 1983-06-24 | 1985-12-10 | Inco Selective Surfaces, Inc. | Process for producing composite material by milling the metal to 50% saturation hardness then co-milling with the hard phase |
| US4619699A (en) * | 1983-08-17 | 1986-10-28 | Exxon Research And Engineering Co. | Composite dispersion strengthened composite metal powders |
| EP0151490B1 (en) * | 1984-02-09 | 1991-01-16 | Toyota Jidosha Kabushiki Kaisha | Process for producing ultra-fine ceramic particles |
| JPS60175537A (en) * | 1984-02-22 | 1985-09-09 | Toyota Motor Corp | Preparation of ultra-fine ceramic particles |
| US4557766A (en) * | 1984-03-05 | 1985-12-10 | Standard Oil Company | Bulk amorphous metal alloy objects and process for making the same |
| US4605631A (en) * | 1984-03-19 | 1986-08-12 | Norton Company | Advanced preparation of ceramic powders |
| GB2156854B (en) * | 1984-04-06 | 1987-03-11 | Atomic Energy Authority Uk | Titanium nitride dispersion strengthened alloys |
| US4750932A (en) * | 1985-04-15 | 1988-06-14 | Gte Products Corporation | Refractory metal silicide sputtering target |
| DE3515167A1 (en) * | 1985-04-26 | 1986-10-30 | Siemens AG, 1000 Berlin und 8000 München | METHOD FOR PRODUCING A METALLIC BODY FROM AN AMORPHOUS ALLOY |
| DE3518706A1 (en) * | 1985-05-24 | 1986-11-27 | Kernforschungszentrum Karlsruhe Gmbh, 7500 Karlsruhe | METHOD FOR PRODUCING MOLDED BODIES WITH IMPROVED ISOTROPICAL PROPERTIES |
| DE3525056A1 (en) * | 1985-07-13 | 1987-01-22 | Metallgesellschaft Ag | METHOD FOR PRODUCING A MECHANICALLY ALLOYED COMPOSITE POWDER |
| DE3669450D1 (en) * | 1985-08-13 | 1990-04-19 | Siemens Ag | METHOD FOR PRODUCING A METALLIC BODY FROM A PARTICULAR AMORPHOUS ALLOY WITH AT LEAST PARTIAL MAGNETIC COMPONENTS. |
| DE3601794A1 (en) * | 1986-01-22 | 1987-07-23 | Georg Dr Ing Gliemeroth | Thermal-shock-resistant ceramic material and process for its manufacture |
| KR900007839B1 (en) * | 1986-01-27 | 1990-10-20 | 더 다우 케미칼 캄파니 | Novel composite ceramics with in proved toughness |
| EP0232772B1 (en) * | 1986-02-05 | 1989-12-27 | Siemens Aktiengesellschaft | Process for preparing a pulverulent amorphous material by way of a milling process |
| CH665849A5 (en) * | 1986-05-29 | 1988-06-15 | Cendres & Metaux Sa | METHOD FOR PRODUCING AMORPHOUS ALLOYS. |
| DE3637506A1 (en) * | 1986-11-04 | 1988-05-05 | Bayer Ag | METHOD FOR PRODUCING ENGINEERING-CERAMIC POWDERS WITH ADDITIVES |
| US4836849A (en) * | 1987-04-30 | 1989-06-06 | Westinghouse Electric Corp. | Oxidation resistant niobium alloy |
| US4891059A (en) * | 1988-08-29 | 1990-01-02 | Battelle Development Corporation | Phase redistribution processing |
-
1987
- 1987-12-04 DE DE19873741119 patent/DE3741119A1/en not_active Withdrawn
-
1988
- 1988-11-24 EP EP88119570A patent/EP0319786B1/en not_active Expired - Lifetime
- 1988-12-02 CA CA000584923A patent/CA1320940C/en not_active Expired - Fee Related
- 1988-12-05 JP JP63306213A patent/JPH01208401A/en active Pending
- 1988-12-05 US US07/279,646 patent/US5149381A/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0288785A2 (en) * | 1987-04-29 | 1988-11-02 | Fried. Krupp AG Hoesch-Krupp | Process for preparing a material with a nanocrystalline structure |
Also Published As
| Publication number | Publication date |
|---|---|
| CA1320940C (en) | 1993-08-03 |
| JPH01208401A (en) | 1989-08-22 |
| EP0319786A1 (en) | 1989-06-14 |
| US5149381A (en) | 1992-09-22 |
| DE3741119A1 (en) | 1989-06-15 |
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