EP0439775A1 - Molybdenum material, especially for making lamps - Google Patents
Molybdenum material, especially for making lamps Download PDFInfo
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- EP0439775A1 EP0439775A1 EP90124464A EP90124464A EP0439775A1 EP 0439775 A1 EP0439775 A1 EP 0439775A1 EP 90124464 A EP90124464 A EP 90124464A EP 90124464 A EP90124464 A EP 90124464A EP 0439775 A1 EP0439775 A1 EP 0439775A1
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- molybdenum
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
- C22C27/04—Alloys based on tungsten or molybdenum
Definitions
- molybdenum material is to be understood as meaning materials which are used for various purposes, preferably in lamp construction.
- the end product of molybdenum production which is initially available as a sintered rod, is then only further processed purely mechanically, so that nothing changes in the chemical composition.
- the desired primary materials are created by rolling, hammering and drawing. More specifically, wires or pins are initially created in these processes. Tubes or strip material for the film production are then in turn produced from pins or wires as semi-finished products.
- Another object is to simplify the process for producing molybdenum material and to make it more cost-effective.
- a suitable additional doping with aluminum has now succeeded in overcoming both difficulties.
- Aluminum chemically binds the potassium and silicon to a high-temperature resistant compound and thus holds the potassium, which is otherwise in an uncontrolled manner during the reduction process would evaporate partially (ie up to 50%!).
- a desired, precisely defined amount of potassium can now be recorded in the molybdenum material. 0.8 to 2.0 times the potassium is particularly advantageous.
- the potassium previously had to be over-doped, so that during the manufacturing process a portion that could not be precisely determined evaporated, which in turn led to a dispersion of the material properties. This is now prevented by the addition of aluminum.
- silicon silicon.
- This positive property is achieved by adding 80-600 ppm by weight of aluminum; particularly good results are shown when using 100-300 ppm.
- the potassium-stabilizing effect of aluminum is masked by its gettering properties, in particular for O 2 (cf. Mikrochimica Acta, 1987, I, pp. 437-444).
- the thermal and mechanical behavior is also affected; in particular, this material is no longer suitable for lamp manufacture.
- a first type of molybdenum uses a doping of approx. 160 ppm aluminum, 275 ppm potassium and 500 ppm silicon.
- the gap is less than 1%, while the number of bends is 11.5. These values are measured on a wire with a diameter of 600 ⁇ m.
- a second type of molybdenum uses a doping of approximately 150 ppm aluminum, 150 ppm potassium and 300 ppm silicon. The clearance is around 8%, while the number of bends is 6, again measured on a wire with a diameter of 600 ⁇ m.
- Each of the two exemplary embodiments is suitable on its own for encompassing the wide range of applications that have hitherto been covered by various types of molybdenum.
- the invention can also be targeted can be used to optimize the crystal structure of the molybdenum material with regard to a very specific application, since the type of structure largely determines the properties of the material.
- This table shows the improvement of the properties, in particular the reduction in the variation in the potassium content, in an impressive manner.
- the process for producing the molybdenum material runs in principle according to the Coolidge process:
- the starting material for the production of the molybdenum products is MoO3 with a purity of 99.97% by weight.
- the MoO3 is reduced to Mo via MoO2 at temperatures of approx. 500 - 600 ° C (1st step) or 1000 - 1100 ° C (2nd step).
- These reductions in molybdenum oxide are carried out in a manner known per se using an H2 / N2 mixture and pure H2 gas.
- a rotary kiln is advantageously used instead of a feed oven to be equipped with boats.
- the molybdenum trioxide which is initially present as a powder, is added in a manner known per se as an aqueous potassium silicate solution either before (as was the case in embodiment 2) or after (as in the case of embodiment 1) the first reduction as dopants.
- the aluminum is added as nitrate (Al (NO3) 3).
- Al (NO3) 3 nitrate
- AlCl3 another unstable aluminum compound
- a compound of high stability for example Al2O3 is unsuitable since the aluminum would not be released in spite of the high temperatures during the reductions.
- the molybdenum powder is pressed on hydraulic presses in steel matrices. Presintering may be advantageous at this point. Then the usual high sintering takes place in the direct current passage (5000 A) in a sinter bell at temperatures up to 2000 ° C. This process is used more with higher doping (embodiment 1). Alternatively, this process can now be carried out in a push-through furnace to increase capacity and save energy. which is mainly used for lower doping (embodiment 2). The sintered rod formed is then processed into molybdenum wire by rolling, hammering and drawing.
- This wire can now be used as a power supply, holder pin or so-called electrode (eg for automotive halogen light bulbs) or as a core wire for the manufacture of tungsten filaments.
- the strip material for the foils can be obtained from the molybdenum wire by further rolling, while the tubes are produced by rolling the wire and then longitudinally bending it into a "tube".
- the doping of the molybdenum with potassium, silicon, aluminum (eg 275 ppm K) according to the invention has nothing to do with the coincidentally similar doping of the tungsten with the same substances (eg 75 ppm K). While according to the invention the doping in the case of molybdenum brings about an improvement in a whole series of properties, in the case of tungsten this doping is primarily responsible for the growth in the length of the grains, which is ultimately intended to prevent the tungsten wire from sagging. The powder metallurgical behavior of both elements is also not comparable (tungsten is sintered at 2800 ° C). The reactions of molybdenum when doping and reducing differ fundamentally from those of tungsten.
- the reason is considered to be the considerably weaker binding energy of the molybdenum compounds compared to corresponding tungsten compounds.
- molybdenum in contrast to tungsten, in the case of molybdenum, no stable ß-phase is formed during the reduction, which means that the Potassium in the crystal lattice - as happens with tungsten - would allow.
- the effect of doping with molybdenum can therefore be characterized as a surface effect with respect to the crystal structure.
- the molybdenum wire according to the invention is used, for example, in a motor vehicle halogen incandescent lamp which has a cylindrical bulb made of hard glass or quartz glass, in which the two luminous elements for low beam and high beam are held by means of three current leads. A dimming screen may also be provided. Such a lamp is described for example in DE-OS 28 29 677.
- the power supply lines and possibly also the anti-dazzle shield are made from molybdenum wire with the addition of 150 ppm aluminum, 150 ppm potassium and 300 ppm silicon.
- the molybdenum wire can be used for the holder pins and foils, in the case of a hard glass piston it is used for the continuous power supply (electrodes).
- a high-voltage halogen incandescent lamp pinched on one or two sides with a long axial lamp or a halogen lamp pinched on one side with a U-shaped or V-shaped lamp for support of the filament, in the first case the power supply remote from the base can be supported in the bulb, as described in DE-GM 88 12 010. In the case of a festoon lamp, support brackets for the luminous element can be provided (for example EP-OS 150 503). Finally, in the third case, the U-shaped or V-shaped lamp body can be held at the end remote from the base by a frame (see, for example, EP-OS 173 995). The above preferred exemplary embodiment is also used in these cases.
- the filament wire is wound onto a core wire made of molybdenum, which is ultimately released again by immersion in an acid.
Abstract
Description
Diese Anmeldung steht in engem Zusammenhang mit der Parallelanmeldung Nr. ... (Az. GR 90 P 5502). Die Erfindung geht aus von einem Molybdänmaterial nach dem Oberbegriff des Anspruchs 1.This application is closely related to parallel application No. ... (Az. GR 90 P 5502). The invention is based on a molybdenum material according to the preamble of claim 1.
Unter dem Begriff Molybdänmaterial sollen im folgenden Vormaterialien verstanden werden, die für verschiedene Zwecke, vorzugsweise im Lampenbau, angewendet werden. Das zunächst als Sinterstab vorliegende Endprodukt der Molybdänherstellung wird anschließend nur noch rein mechanisch weiterverarbeitet, so daß sich an der chemischen Zusammensetzung nichts mehr ändert. Durch Walzen, Hämmern und Ziehen entstehen die gewünschten Vormaterialien. Genauer gesagt entstehen bei diesen Prozessen zunächst Drähte oder Stifte. Röhrchen oder Bandmaterial für die Folienherstellung werden dann als Halbzeug wiederum aus Stiften oder Drähten hergestellt.In the following, the term molybdenum material is to be understood as meaning materials which are used for various purposes, preferably in lamp construction. The end product of molybdenum production, which is initially available as a sintered rod, is then only further processed purely mechanically, so that nothing changes in the chemical composition. The desired primary materials are created by rolling, hammering and drawing. More specifically, wires or pins are initially created in these processes. Tubes or strip material for the film production are then in turn produced from pins or wires as semi-finished products.
Die Dotierung von Molybdänmaterial mit Kalium und Silizium in Form von Kaliumsilikatlösung ist schon seit längerem bekannt. Beispielsweise ist in der US-PS 4 419 602 beschrieben, diese Elemente als Zusatzstoffe für Molybdän-Dichtungsfolien zu verwenden, um die Rekristallisationstemperatur zu erhöhen. Es hat sich jedoch gezeigt, daß die Materialeigenschaften des dotierten Molybdäns eine erhebliche Streubreite aufweisen, so daß, falls gewünscht, ein Material mit genau definierten Eigenschaften bisher durch Mischen verschiedener Komponenten in einem sehr diffizilen Arbeitsschritt nachträglich eingestellt werden muß.The doping of molybdenum material with potassium and silicon in the form of potassium silicate solution has been known for a long time. For example, U.S. Patent 4,419,602 describes these elements as Use additives for molybdenum sealing foils to increase the recrystallization temperature. However, it has been shown that the material properties of the doped molybdenum have a considerable spread, so that, if desired, a material with precisely defined properties has hitherto had to be adjusted subsequently by mixing different components in a very difficult working step.
Es ist Aufgabe der vorliegenden Erfindung eine Qualitätsverbesserung der Materialeigenschaften von Molybdän-Halbzeug, insbesondere für die Lampenindustrie, zu erzielen und den Ausschuß zu senken.It is an object of the present invention to improve the quality of the material properties of semi-finished molybdenum, in particular for the lamp industry, and to reduce rejects.
Eine weitere Aufgabe ist es, das Verfahren zur Herstellung von Molybdänmaterial zu vereinfachen und kostengünstiger zu gestalten.Another object is to simplify the process for producing molybdenum material and to make it more cost-effective.
Diese Aufgaben werden durch die kennzeichnenden Merkmale des Anspruchs 1 gelöst. Besonders vorteilhafte Ausgestaltungen der Erfindung finden sich in den Unteransprüchen.These objects are achieved by the characterizing features of claim 1. Particularly advantageous embodiments of the invention can be found in the subclaims.
In den letzten Jahren haben sich die Anforderungen an die thermische und mechanische Belastbarkeit des Molybdänmaterials ständig erhöht, insbesondere im Zusammenhang mit der Entwicklung von Halogenglühlampen und PAR-Lampen. Dies führte zunächst zu einer weitgehenden Spezialisierung der Molybdänmaterialien für verschiedene Einsatzgebiete. Beispielsweise wurden verschiedene Molybdänmaterialien für Kerndrähte, gasdichte Einschmelzstifte, Halterdrähte und Dichtungsfolien hergestellt. Während bei Halterdrähten eine hohe und konstante Dehnung die wichtigste Eigenschaft ist, kommt es bei Dichtungsfolien vor allem auf eine hohe Duktilität und hohe Rekristallisationstemperatur an. Andererseits ist bei Einschmelzstiften und Kerndrähten die geeignete Kombination einer hohen Rekristallisationstemperatur mit einer hohen Biegezahl die entscheidende Größe. Bei Einschmelzstiften spielt zudem die Spaltfreiheit eine wesentliche Rolle.In recent years, the requirements for the thermal and mechanical resilience of the molybdenum material have increased continuously, especially in connection with the development of halogen incandescent lamps and PAR lamps. This initially led to extensive specialization of molybdenum materials for various areas of application. For example, various molybdenum materials for core wires, gas-tight sealing pins, holder wires and sealing foils were manufactured. While with holder wires a high and constant elongation the The most important property is that a high degree of ductility and a high recrystallization temperature are important for sealing foils. On the other hand, with melting pins and core wires, the appropriate combination of a high recrystallization temperature with a high number of bends is the decisive factor. Gap freedom also plays an important role in melting pens.
Diesen verschiedenen Anforderungsprofilen wurde durch eine jeweils unterschiedliche Dotierung mit Kalium und eventuell auch Silizium Rechnung getragen. Dadurch wurde die Herstellung des Halbzeugs sehr kompliziert und unrationell, weil die Maschinen immer wieder umgerüstet und neu programmiert werden mußten. Zudem bestand die Gefahr der Verwechslung der verschiedenen Materialien bei der Weiterverarbeitung.These different requirement profiles were taken into account by different doping with potassium and possibly also silicon. This made the production of the semi-finished product very complicated and inefficient, because the machines had to be retooled and reprogrammed again and again. There was also the risk of confusing the different materials during further processing.
Darüber hinaus ergab sich lange Zeit ein scheinbar unlösbares Problem in der hohen Streubreite der jeweiligen Dotierungen. Man stand vor der Wahl, entweder einen hohen Ausschuß zu akzeptieren oder das Material trotz schlechterer Qualität weiterzuverarbeiten. Beispielsweise vergrößert eine hohe Spaltigkeit das Risiko, daß in einer Lampe der Halogenkreislauf durch Verunreinigungen gestört wird, was zu Frühausfällen führt.In addition, there appeared to be an apparently unsolvable problem in the high spread of the respective dopings for a long time. The choice was either to accept a high committee or to process the material despite the poor quality. For example, a high gap increases the risk that the halogen circuit in a lamp is disturbed by impurities, which leads to early failures.
Durch eine geeignete zusätzliche Dotierung mit Aluminium ist es nun gelungen, beide Schwierigkeiten zu überwinden. Aluminium bindet das Kalium und Silizium chemisch zu einer hochtemperaturbeständigen Verbindung und hält damit das Kalium, welches ansonsten in unkontrollierter Weise beim Reduktionsprozeß teilweise (d.h. bis zu 50 %!) verdampfen würde, zurück. Durch die gezielte Zugabe einer bestimmten Menge Aluminiums kann jetzt eine gewünschte, genau definierte Menge an Kalium im Molybdänmaterial festgehalten werden. Besonders vorteilhaft ist das 0,8 - 2,0- fache an Kalium. Ohne gleichzeitige Zugabe von Aluminium mußte das Kalium bisher zunächst überdotiert werden, so daß im Laufe des Herstellungsprozesses eine nicht genau festzulegende Teilmenge ausdampfte, was wiederum zur Streuung der Materialeigenschaften führte. Dies wird jetzt durch die Zugabe von Aluminium verhindert. Ähnliches gilt für Silizium.A suitable additional doping with aluminum has now succeeded in overcoming both difficulties. Aluminum chemically binds the potassium and silicon to a high-temperature resistant compound and thus holds the potassium, which is otherwise in an uncontrolled manner during the reduction process would evaporate partially (ie up to 50%!). Through the targeted addition of a certain amount of aluminum, a desired, precisely defined amount of potassium can now be recorded in the molybdenum material. 0.8 to 2.0 times the potassium is particularly advantageous. Without the simultaneous addition of aluminum, the potassium previously had to be over-doped, so that during the manufacturing process a portion that could not be precisely determined evaporated, which in turn led to a dispersion of the material properties. This is now prevented by the addition of aluminum. The same applies to silicon.
Diese positive Eigenschaft wird erzielt durch die Zugabe von 80-600 Gew.-ppm Aluminium; besonders gute Ergebnisse zeigen sich bei Verwendung von 100-300 ppm. Bei der Zugabe einer erheblich größeren Menge an Aluminium (im Promille- und Prozentbereich) wird der kaliumstabilisierende Effekt des Aluminiums durch seine Gettereigenschaft, insbesondere für O2, überdeckt (vgl. Mikrochimica Acta, 1987, I, S. 437-444). Gleichzeitig wird auch das thermische und mechanische Verhalten dabei beeinträchtigt; insbesondere ist dieses Material für die Lampenherstellung nicht mehr geeignet.This positive property is achieved by adding 80-600 ppm by weight of aluminum; particularly good results are shown when using 100-300 ppm. When a considerably larger amount of aluminum is added (in the range per percent and percent), the potassium-stabilizing effect of aluminum is masked by its gettering properties, in particular for O 2 (cf. Mikrochimica Acta, 1987, I, pp. 437-444). At the same time, the thermal and mechanical behavior is also affected; in particular, this material is no longer suitable for lamp manufacture.
Überraschenderweise hat sich aber gezeigt, daß bei der oben angegebenen sparsamen Dotierung mit Aluminium die Eigenschaften des Molybdänmaterials erheblich verbessert werden können. Es laßt sich ein Molybdänmaterial erzielen, das allen bisher verfügbaren spezifischen Molybdänmaterialien überlegen ist. Dadurch ist es sogar möglich geworden, die verschiedenen o.g. Molybdänmaterialien durch eine einheitliche und zudem verbesserte Molybdäntype zu ersetzen, was die Kosten für die Herstellung senkt. Darüber hinaus ergibt sich bei derartigen neuen Molybdäntypen die Möglichkeit einer Energieeinsparung um bis zu 25 %, da jetzt u.U. auf ein Sintern in direktem Stromdurchgang (Hochsinterung) verzichtet werden kann (vgl. hierzu C. Agte/J. Vacek, Wolfram und Molybdän, Akademie-Verlag, Berlin, 1959, insbes. Kap. 6). Stattdessen kann jetzt der Sinterprozeß in Durchschuböfen bei erheblich niedrigeren Temperaturen (ca. 1700 °C gegenüber ca. 2000 °C) durchgeführt werden.Surprisingly, however, it has been shown that the properties of the molybdenum material can be considerably improved with the economical doping with aluminum given above. A molybdenum material can be obtained which is superior to all specific molybdenum materials available to date. This has even made it possible to pass through the various molybdenum materials mentioned above to replace a uniform and improved type of molybdenum, which lowers the cost of production. In addition, with such new molybdenum types there is the possibility of energy savings of up to 25%, since sintering in direct current passage (high sintering) can now be dispensed with (cf. C. Agte / J. Vacek, Wolfram and Molybdenum, Akademie -Verlag, Berlin, 1959, especially chapter 6). Instead, the sintering process can now be carried out in push-through furnaces at considerably lower temperatures (approx. 1700 ° C compared to approx. 2000 ° C).
Im folgenden sollen zwei Ausführungsbeispiele näher erläutert werden.Two exemplary embodiments are to be explained in more detail below.
Eine erste Molybdäntype verwendet eine Dotierung von ca. 160 ppm Aluminium, 275 ppm Kalium und 500 ppm Silizium. Die Spaltfreiheit beträgt unter 1 %, während die Biegezahl bei 11,5 liegt. Diese Werte sind jeweils gemessen an einem Draht mit 600 µm Durchmesser.A first type of molybdenum uses a doping of approx. 160 ppm aluminum, 275 ppm potassium and 500 ppm silicon. The gap is less than 1%, while the number of bends is 11.5. These values are measured on a wire with a diameter of 600 µm.
Eine zweite Molybdäntype verwendet eine Dotierung von ca. 150 ppm Aluminium, 150 ppm Kalium und 300 ppm Silizium. Die Spaltfreiheit beträgt etwa 8 %, während die Biegezahl bei 6 liegt, wiederum gemessen an einem Draht mit 600 µm Durchmesser.A second type of molybdenum uses a doping of approximately 150 ppm aluminum, 150 ppm potassium and 300 ppm silicon. The clearance is around 8%, while the number of bends is 6, again measured on a wire with a diameter of 600 µm.
Beide Ausführungsbeispiele sind jedes für sich dazu geeignet, das breite Anwendungsspektrum, das bisher durch verschiedene Molybdäntypen abgedeckt wurde, allein zu umfassen.Each of the two exemplary embodiments is suitable on its own for encompassing the wide range of applications that have hitherto been covered by various types of molybdenum.
Die Erfindung kann jedoch umgekehrt auch gezielt dazu benutzt werden, das Kristallgefüge des Molybdänmaterials im Hinblick auf eine ganz bestimmte Anwendung zu optimieren, da die Art des Gefüges maßgeblich die Eigenschaften des Materials bestimmt.Conversely, the invention can also be targeted can be used to optimize the crystal structure of the molybdenum material with regard to a very specific application, since the type of structure largely determines the properties of the material.
Die in den beiden Ausführungsbeispielen beschriebenen besonders bevorzugten Molybdänmaterialien (Spalte I) haben als Draht folgende Eigenschaften gegenüber herkömmlichen Materialien (in Spalte II ist jeweils der beste verfügbare Wert des herkömmlichen Materials angegeben):
Diese Tabelle zeigt die Verbesserung der Eigenschaften, insbesondere die Verringerung in der Streubreite des Kaliumgehalts, auf eindrucksvolle Weise.This table shows the improvement of the properties, in particular the reduction in the variation in the potassium content, in an impressive manner.
Das Verfahren zur Herstellung des Molybdänmaterials läuft im Prinzip nach dem Coolidge-Verfahren ab: Ausgangsstoff für die Herstellung der Molybdänerzeugnisse ist MoO₃ mit einer Reinheit von 99,97 Gew.-%. In zwei Schritten wird das MoO₃ über MoO₂ zu Mo reduziert bei Temperaturen von ca. 500 - 600 °C (1. Schritt) bzw. 1000 - 1100 °C (2. Schritt). Diese Reduktionen des Molybdänoxids werden in an sich bekannter Weise mit einem H₂/N₂-Gemisch und reinem H₂-Gas durchgeführt. Vorteilhaft wird ein Drehrohrofen statt eines mit Schiffchen zu bestückenden Vorschubofens verwendet. Dem zunächst als Pulver vorliegenden Molybdäntrioxid werden entweder vor (wie im Fall des Ausführungsbeispiels 2 geschehen) oder nach (wie im Fall des Ausführungsbeispiels 1 geschehen) der ersten Reduktion als Dotierstoffe Kalium und Silizium in an sich bekannter Weise als wässerige Kaliumsilikatlösung zugegeben. Gleichzeitig wird das Aluminium als Nitrat (Al (NO₃)₃) beigefügt. Denkbar wäre auch die Verwendung einer anderen instabilen Aluminiumverbindung, z.B. AlCl₃. Hingegen ist eine Verbindung hoher Stabilität, z.B. Al₂O₃, ungeeignet, da das Aluminium trotz der hohen Temperaturen bei den Reduktionen nicht freigesetzt würde.The process for producing the molybdenum material runs in principle according to the Coolidge process: The starting material for the production of the molybdenum products is MoO₃ with a purity of 99.97% by weight. In two steps the MoO₃ is reduced to Mo via MoO₂ at temperatures of approx. 500 - 600 ° C (1st step) or 1000 - 1100 ° C (2nd step). These reductions in molybdenum oxide are carried out in a manner known per se using an H₂ / N₂ mixture and pure H₂ gas. A rotary kiln is advantageously used instead of a feed oven to be equipped with boats. The molybdenum trioxide, which is initially present as a powder, is added in a manner known per se as an aqueous potassium silicate solution either before (as was the case in embodiment 2) or after (as in the case of embodiment 1) the first reduction as dopants. At the same time, the aluminum is added as nitrate (Al (NO₃) ₃). It would also be conceivable to use another unstable aluminum compound, for example AlCl₃. In contrast, a compound of high stability, for example Al₂O₃, is unsuitable since the aluminum would not be released in spite of the high temperatures during the reductions.
Um die gewünschten duktilen Materialien herstellen zu können, wird das Molybdän-Pulver auf hydraulischen Pressen in Stahlmatrizen verpreßt. Unter Umständen ist an dieser Stelle eine Vorsinterung vorteilhaft. Anschließend erfolgt die übliche Hochsinterung im direkten Stromdurchgang (5000 A) in einer Sinterglocke bei Temperaturen bis zu 2000 °C. Dieser Prozeß wird eher bei höheren Dotierungen (Ausführungsbeispiel 1) verwendet. Alternativ kann dieser Prozeß jetzt kapazitätserweiternd und energiesparend in einem Durchschubofen erfolgen, was vor allem bei niedrigeren Dotierungen (Ausführungsbeispiel 2) angewendet wird. Der dabei gebildete Sinterstab wird anschließend durch Walzen, Hämmern und Ziehen zu Molybdändraht verarbeitet. Dieser Draht kann nun als Stromzuführung, Halterstift oder sog. Elektrode eingesetzt werden (z.B. für Kfz-Halogenglühlampen) oder als Kerndraht für die Wolfram-Wendelherstellung. Das Bandmaterial für die Folien kann aus dem Molybdändraht durch weiteres Walzen gewonnen werden, während die Röhrchen durch Walzen des Drahtes und anschließendem Längsbiegen zu einem "Schlauch" hergestellt werden.In order to be able to produce the desired ductile materials, the molybdenum powder is pressed on hydraulic presses in steel matrices. Presintering may be advantageous at this point. Then the usual high sintering takes place in the direct current passage (5000 A) in a sinter bell at temperatures up to 2000 ° C. This process is used more with higher doping (embodiment 1). Alternatively, this process can now be carried out in a push-through furnace to increase capacity and save energy. which is mainly used for lower doping (embodiment 2). The sintered rod formed is then processed into molybdenum wire by rolling, hammering and drawing. This wire can now be used as a power supply, holder pin or so-called electrode (eg for automotive halogen light bulbs) or as a core wire for the manufacture of tungsten filaments. The strip material for the foils can be obtained from the molybdenum wire by further rolling, while the tubes are produced by rolling the wire and then longitudinally bending it into a "tube".
Im übrigen hat die erfindungsgemäße Dotierung des Molybdäns mit Kalium, Silizium, Aluminium (z.B. 275 ppm K) nichts mit der zufälligerweise ähnlichen Dotierung des Wolfram mit den gleichen Substanzen (z.B. 75 ppm K) zu tun. Während erfindungsgemäß beim Molybdän die Dotierung die Verbesserung einer ganzen Reihe von Eigenschaften bewirkt, ist beim Wolfram diese Dotierung vor allem für die Ausbildung des Längenwachstums der Körner verantwortlich, was letztendlich das Durchhängen des Wolframdrahtes verhindern soll. Auch das pulvermetallurgische Verhalten beider Elemente ist nicht vergleichbar (Wolfram wird bei 2800 °C hochgesintert). Die Reaktionen des Molybdäns beim Dotieren und bei der Reduktion unterscheiden sich grundsätzlich von denen des Wolframs. Als Ursache wird die erheblich schwächere Bindungsenergie der Molybdänverbindungen im Vergleich zu entsprechenden Wolframverbindungen angesehen. Beispielsweise bildet sich beim Molybdän im Gegensatz zum Wolfram während der Reduktion keine stabile ß-Phase aus, die den Einbau des Kaliums in das Kristallgitter - wie dies bei Wolfram geschieht - erlauben würde. Die Wirkung der Dotierung bei Molybdän kann daher eher als Oberflächeneffekt in bezug auf das Kristallgefüge charakterisiert werden. Hingegen kann man beim Wolfram von einem Volumeneffekt sprechen.Moreover, the doping of the molybdenum with potassium, silicon, aluminum (eg 275 ppm K) according to the invention has nothing to do with the coincidentally similar doping of the tungsten with the same substances (eg 75 ppm K). While according to the invention the doping in the case of molybdenum brings about an improvement in a whole series of properties, in the case of tungsten this doping is primarily responsible for the growth in the length of the grains, which is ultimately intended to prevent the tungsten wire from sagging. The powder metallurgical behavior of both elements is also not comparable (tungsten is sintered at 2800 ° C). The reactions of molybdenum when doping and reducing differ fundamentally from those of tungsten. The reason is considered to be the considerably weaker binding energy of the molybdenum compounds compared to corresponding tungsten compounds. For example, in contrast to tungsten, in the case of molybdenum, no stable ß-phase is formed during the reduction, which means that the Potassium in the crystal lattice - as happens with tungsten - would allow. The effect of doping with molybdenum can therefore be characterized as a surface effect with respect to the crystal structure. On the other hand, one can speak of a volume effect with tungsten.
Die beim Wolfram gewonnenen Erfahrungen in bezug auf die Dotierung mit Kalium, Silizium und Aluminium lassen sich daher nicht auf die spezifischen Probleme bei der Molybdänherstellung übertragen.The experience gained with tungsten with regard to doping with potassium, silicon and aluminum cannot therefore be transferred to the specific problems in the production of molybdenum.
Der erfindungsgemäße Molybdändraht wird beispielsweise in einer Kfz-Halogenglühlampe eingesetzt, die einen zylindrischen Kolben aus Hartglas oder Quarzglas besitzt, in dem die beiden Leuchtkörper für Abblendlicht bzw. Fernlicht mittels dreier Stromzuführungen gehaltert sind. Unter Umständen ist auch ein Abblendschirm vorgesehen. Eine derartige Lampe ist beispielsweise in der DE-OS 28 29 677 beschrieben. Die Stromzuführungen und evtl. auch der Abblendschirm sind in einem besonders bevorzugten Ausführungsbeispiel aus Molybdändraht mit einem Zusatz von 150 ppm Aluminium, 150 ppm Kalium und 300 ppm Silizium gefertigt. Im Fall eines Kolbens aus Quarzglas kann der Molybdändraht für die Halterstifte und Folien eingesetzt werden, im Fall eines Hartglaskolbens wird er für die durchgehenden Stromzuführungen (Elektroden) verwendet.The molybdenum wire according to the invention is used, for example, in a motor vehicle halogen incandescent lamp which has a cylindrical bulb made of hard glass or quartz glass, in which the two luminous elements for low beam and high beam are held by means of three current leads. A dimming screen may also be provided. Such a lamp is described for example in DE-OS 28 29 677. In a particularly preferred exemplary embodiment, the power supply lines and possibly also the anti-dazzle shield are made from molybdenum wire with the addition of 150 ppm aluminum, 150 ppm potassium and 300 ppm silicon. In the case of a piston made of quartz glass, the molybdenum wire can be used for the holder pins and foils, in the case of a hard glass piston it is used for the continuous power supply (electrodes).
Ein anderes Einsatzgebiet ist eine einseitig oder zweiseitig gequetschte Hochvolthalogenglühlampe mit einem langen axialen Leuchtkörper oder eine einseitig gequetschte Halogenglühlampe mit einem U-förmig oder V-förmig gebogenen Leuchtkörper. Zur Stützung des Leuchtkörpers kann im ersten Fall die sockelferne Stromzuführung im Kolben abgestützt sein, wie im DE-GM 88 12 010 beschrieben. Bei einer Soffittenlampe können Stützhalter für den Leuchtkörper vorgesehen sein (z.B. EP-OS 150 503). Schließlich kann im dritten Fall der U-förmig oder V-förmig gebogene Leuchtkörper am sockelfernen Ende durch ein Gestell gehaltert sein (vgl. z.B. EP-OS 173 995). Auch in diesen Fällen wird obiges bevorzugtes Ausführungsbeispiel verwendet.Another area of application is a high-voltage halogen incandescent lamp pinched on one or two sides with a long axial lamp or a halogen lamp pinched on one side with a U-shaped or V-shaped lamp. For support of the filament, in the first case the power supply remote from the base can be supported in the bulb, as described in DE-GM 88 12 010. In the case of a festoon lamp, support brackets for the luminous element can be provided (for example EP-OS 150 503). Finally, in the third case, the U-shaped or V-shaped lamp body can be held at the end remote from the base by a frame (see, for example, EP-OS 173 995). The above preferred exemplary embodiment is also used in these cases.
Bei der Wendelherstellung wird der Wendeldraht auf einen Kerndraht aus Molybdän aufgewickelt, welcher letztendlich durch Eintauchen in eine Säure wieder herausgelöst wird.During the manufacture of the filament, the filament wire is wound onto a core wire made of molybdenum, which is ultimately released again by immersion in an acid.
Claims (12)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4002974 | 1990-02-01 | ||
| DE4002974A DE4002974A1 (en) | 1990-02-01 | 1990-02-01 | Doped molybdenum material esp. for lamp mfr. - with controlled aluminium content for high quality and low reject rate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0439775A1 true EP0439775A1 (en) | 1991-08-07 |
| EP0439775B1 EP0439775B1 (en) | 1994-10-26 |
Family
ID=6399219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP90124464A Expired - Lifetime EP0439775B1 (en) | 1990-02-01 | 1990-12-17 | Molybdenum material, especially for making lamps |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0439775B1 (en) |
| JP (1) | JP2766081B2 (en) |
| KR (1) | KR0178038B1 (en) |
| AT (1) | ATE113318T1 (en) |
| DE (2) | DE4002974A1 (en) |
| ES (1) | ES2060913T3 (en) |
| HU (1) | HU210281B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE9415217U1 (en) | 1994-09-21 | 1996-01-25 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | High pressure discharge lamp |
| DE19603300C2 (en) * | 1996-01-30 | 2001-02-22 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Electric lamp with molybdenum foil bushings for a lamp vessel made of quartz glass |
| DE19603301C2 (en) * | 1996-01-30 | 2001-02-22 | Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh | Electric lamp with molybdenum foil bushings for a lamp vessel made of quartz glass |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3676083A (en) * | 1969-01-21 | 1972-07-11 | Sylvania Electric Prod | Molybdenum base alloys |
| US4419602A (en) * | 1981-01-23 | 1983-12-06 | Tokyo Shibaura Denki Kabushiki Kaisha | Electric lamp |
| EP0119438A1 (en) * | 1983-02-10 | 1984-09-26 | Kabushiki Kaisha Toshiba | Molybdenum board and process of manufacturing the same |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60194043A (en) * | 1984-03-14 | 1985-10-02 | Toshiba Corp | Tube bulb weld |
| JPS63114935A (en) * | 1986-10-31 | 1988-05-19 | Tokyo Tungsten Co Ltd | Molybdenum crucible and its production |
| JPH0232340B2 (en) * | 1986-12-25 | 1990-07-19 | Tokyo Tungsten Kk | MORIBUDENZAI |
| JPS63192840A (en) * | 1987-02-06 | 1988-08-10 | Tokyo Tungsten Co Ltd | Molybdenum material for dot printer |
-
1990
- 1990-02-01 DE DE4002974A patent/DE4002974A1/en not_active Withdrawn
- 1990-12-03 HU HU908037A patent/HU210281B/en not_active IP Right Cessation
- 1990-12-17 DE DE59007562T patent/DE59007562D1/en not_active Expired - Fee Related
- 1990-12-17 ES ES90124464T patent/ES2060913T3/en not_active Expired - Lifetime
- 1990-12-17 AT AT90124464T patent/ATE113318T1/en not_active IP Right Cessation
- 1990-12-17 EP EP90124464A patent/EP0439775B1/en not_active Expired - Lifetime
-
1991
- 1991-01-28 JP JP3008445A patent/JP2766081B2/en not_active Expired - Lifetime
- 1991-02-01 KR KR1019910001737A patent/KR0178038B1/en not_active IP Right Cessation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3676083A (en) * | 1969-01-21 | 1972-07-11 | Sylvania Electric Prod | Molybdenum base alloys |
| US4419602A (en) * | 1981-01-23 | 1983-12-06 | Tokyo Shibaura Denki Kabushiki Kaisha | Electric lamp |
| EP0119438A1 (en) * | 1983-02-10 | 1984-09-26 | Kabushiki Kaisha Toshiba | Molybdenum board and process of manufacturing the same |
Non-Patent Citations (3)
| Title |
|---|
| DRUCKSCHRIFT DER FA. "METALLWERKE PLANSEE" 1980, Seiten 8-13, Reutte, Tirol; "Molybdän" * |
| PATENT ABSTRACTS OF JAPAN Band 12, Nr. 438 (C-544)(3285), 17. November 1988; & JP - A - 63162834 (TOKYO TUNGSTEN) 06.07.1988 * |
| PATENT ABSTRACTS OF JAPAN Band 9, Nr. 175 (C-292)(1898), 19. Juli 1985; & JP - A - 6046345 (TOUKIYOU TUNGSTEN) 13.03.1985 * |
Also Published As
| Publication number | Publication date |
|---|---|
| DE4002974A1 (en) | 1991-08-08 |
| HUT62946A (en) | 1993-06-28 |
| DE59007562D1 (en) | 1994-12-01 |
| HU908037D0 (en) | 1991-06-28 |
| KR910021490A (en) | 1991-12-20 |
| KR0178038B1 (en) | 1999-02-18 |
| JP2766081B2 (en) | 1998-06-18 |
| ES2060913T3 (en) | 1994-12-01 |
| ATE113318T1 (en) | 1994-11-15 |
| JPH04214836A (en) | 1992-08-05 |
| HU210281B (en) | 1995-03-28 |
| EP0439775B1 (en) | 1994-10-26 |
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