WO2008009154A1 - A method for producing filament for halogen lamp - Google Patents
A method for producing filament for halogen lamp Download PDFInfo
- Publication number
- WO2008009154A1 WO2008009154A1 PCT/CN2006/001390 CN2006001390W WO2008009154A1 WO 2008009154 A1 WO2008009154 A1 WO 2008009154A1 CN 2006001390 W CN2006001390 W CN 2006001390W WO 2008009154 A1 WO2008009154 A1 WO 2008009154A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- rhenium
- tungsten
- filament
- wire
- grain
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01K—ELECTRIC INCANDESCENT LAMPS
- H01K1/00—Details
- H01K1/02—Incandescent bodies
- H01K1/04—Incandescent bodies characterised by the material thereof
- H01K1/10—Bodies of metal or carbon combined with other substance
Definitions
- the invention relates to a tungsten-rhenium filament for high temperature working condition, especially used for halogen incandescent lamps.
- This invention also relates to a tungsten wire which can increase the re-crystallization temperature comprising to the non-sag tungsten wire.
- the invention relates to a tungsten-rhenium filament for high temperature working condition, especially used for halogen incandescent lamps.
- This invention also relates to a tungsten wire which can increase the re-crystallization temperature comprising to the non-sag tungsten wire.
- the rhenium-tungsten wire for halogen incandescent lamps can work under a high temperature and have a high re-crystallization temperature. It can be used as stage- and studio lamps, and special headlamps.
- the typical high operation temperature is between 2900 centigrade and 3200 centigrade and it has a long working time. It can result the traditional NS-Doped tungsten wire's short working time effectively, it but also has a large Long to Wide of the Grain and has a low sag value. On the other hand; it can improve the non-sag properties of the filaments, particularly at high temperature.
- Rhenium-tungsten wire can increase the re-crystallization temperature and strength the grain boundary structure. The amount of the rhenium added in tungsten powder is minimal and between 0.4" 0.8% by weight. It can not increase much the cost of the manufacture of the tungsten wire.
- Tungsten ingots intended for making tungsten filaments also contain a very minor amount of dopants such as potassium, aluminium and silicon.
- dopants such as potassium, aluminium and silicon.
- the process cycle and the equipments are same to the traditional NS-sag tungsten wire while the process temperature, process compressibility and deformation velocity will be changed to fit for the rhenium-tungsten alloy, for the rhenium-tungsten alloy is solid solution alloy.
- the effect of ASK on the traditional tungsten wire is well known for the filaments of incandesbent lamps, but the AKS dopants can not resolve the problem of decreased re-crystallization temperature.
- the addition of ASK is mostly used to form the potassium bubble which can urge the interlocking grain structure.
- the main reason of the formation of the voids is the potassium which was added in the former procedure.
- the rhenium-tungsten alloy is solid solution alloy. So the solid solution atoms can strength the grain structure especially the grain boundary structure which can compensates the negative effect of the potassium. It was considered that the addition of at least 0.4% by weight rhenium is necessary can make up for the void forming effect in filaments operating at high temperature.
- the grain structure and the wire's mechanical properties improve.
- the little amount (as little as 0.4%) can increase the temperature for the complete re-crystallization for rhenium-tungsten filaments above the critical value of 2300-2400 centigrade during the re-crystallization.
- improving the rhenium-tungsten filament initial re-crystallization temperature above the annealing temperature of the filament during the fabricating the filament is needed.
- the grain structure is optimum and the Long to Wide of the grain will exceed 15 while the little amount rhenium may increase the cost of the wire little and it will be more economical.
- the present invention has been made in view of the foregoing disadvantage of the prior art.
- a filament made of a rhenium-tungsten alloy wire.
- the re-crystallization temperature of the wire exceeds 2200 [deg.] C.
- the alloy wire also include the potassium, aluminium and silicon additive.
- the dopants amount is between 80-100ppm.
- the rhenium content is of 0.4-0.8% by weight.
- the invention includes the following fabricating processing step.
- the powder was prepared with the dopants ASK and the alloy element rhenium.
- the amount of the dopants is between 80 ⁇ 100ppm.
- the powder was mixed for a suitable time and pressed under 160 " 200MPa according to the dimension of the ingots.
- the ingots were sintered with direct current.
- the wire was draw from the sintered alloys.
- the solid solution atom can strengthen the grain boundary, the tensile strength increase greatly, which can decrease the wire broken in fabricating the filament and improving the productive efficiency.
- Rhenium has high electrical resistivity, so the rhenium-tungsten wire has higher cold resistance which can shorten the filament effective length in designing the filament, so the materials can be saved which can compensate the cost of the added rhenium.
- Fig 1 is a graphic representation showing the filament of the halogen lamp.
- Fig 2 is a graphic representation showing the metallograph of the processing state of ⁇ 8.9mm.
- Fig 3 is a graphic representation showing the complete re-crystallization grain structure of ⁇ . ⁇ mm.
- Fig 4 is a graphic representation showing the grain structure of started re-crystallization.
- Fig 5 is a graphic representation showing the grain structure of complete re-crystallization.
- the dopants ASK potassium, aluminium, silicon
- the content of the potassium is between 80-100ppm, and it has a rhenium content of 0.4-0.8% by weight.
- the rhenium atom is well-distributed in the tungsten matrix.
- the amount of the potassium ensures the potassium bubble bunched during the drawing process.
- Rhenium can strengthen the grain boundary and improve the re-crystallization temperature.
- the synthetic action of potassium bubble and rhenium achieve a good grain structure and the filament also has a high initial re-crystallization temperature.
- the initial re-crystallization temperature will be above 2100[deg.] C.
- the Long to Wide of the grain can exceed 15.
- Rhenium-tungsten alloy is solid solution alloy, solid solution atom strengthen the crystal lattice of tungsten; so the drawing temperature of the rhenium-tungsten wire must higher than the doped-tungsten wire, as it was explained above paragraph.
- the tungsten wire is strengthened by the rhenium because of the solid solution strength.
- the start and the end re-crystallization temperature are improved greatly, while the tensile strength is improved.
- the representative rhenium-tungsten wire comparing to the traditional NS-doped tungsten wire characteristics are shown in the table below.
- Test tungsten metal sample with 83ppm potassium content and 0.45% and 0.60% by weight rhenium-tungsten alloys were produced. Form the two samples, tungsten wires were made for the filament production. The most important characteristic of the wire at a diameter of 0.39mm were controlled and stable including high temperature strength, cracking level, starting re-crystallization temperature, Long to Wide of grain, high temperature doping value, etc. The quality of rhenium-tungsten wire is higher obviously than traditional NS-doped tungsten wire.
- Fig 2 is the rhenium-tungsten alloy with 0.45% by weight after forging, the microstructure of the grain is typical process state.
- the grain is uniform which provide an excellent structure for the annealing and the following forging. In this process the temperature and deformation rate must be controlled, or much crack will be produced.
- the average deformation ratio is about 25" 30%. The value is adjusted according to the actual condition.
- Fig 3 is the rhenium-tungsten alloy after complete annealing.
- the process homogenization determines the re-crystallization structure and the potassium bubble deformation. It is also the determining factor for the following process.
- the propose of this process can eliminate the cold hardening and fine the grains.
- the starting point of the re-crystallization temperature of the rhenium-tungsten wire at a diameter of 0.39mm is 2250 "C . Because thermal radiation, the core of the wire temperature is higher than the surface, re-crystallization begin with the core of the wire.
- fig 5 illustrates the elongated interlocking grain structure. The Long to Wide of Grain exceed 15 which assure the high temperature property of the wire. The excellent grain structure determines the filament with a lower sagged value which can increase greatly the filament life.
- rhenium can strengthen the grain boundary structure.
- the voids on the grain boundaries can be avoided greatly, so during the using of the filament there are few hot pots appearance.
- the rhenium-tungsten filament has the lower dropped value comparing to the traditional AKS NS-tungsten filament, the filament screw-pitch is very well-distributed during the using process which can bring the well-distributed temperature of the filament. Because of the virtues of the filament, the tungsten evaporation is well-distributed, so few hot pots appear. The life time of the filament can be increased largely.
- the rhenium-tungsten filament which recommended is applicable for all type of lamps, and it is especially used for tungsten halogen lamps.
- the application of this filament will largely increase the life time of the lamps and reduce the breakage of finished lamps during handling and shipping.
- the tungsten wire is strengthened by the rhenium because of the solid solution strength.
- the start and the end re-crystallization temperature are improved greatly, while the tensile strength is improved.
- the representative rhenium-tungsten wire comparing to the traditional NS-doped tungsten wire characteristics are shown in the table below.
Landscapes
- Resistance Heating (AREA)
Abstract
The NS-Doped-tungsten wire has a lower re-crystallization temperature and long to wide of the grain comprising to the tungsten-rhenium alloy wire. The filament comprises an aluminium-potassium-silicon (AKS) additive. The overlapped grain microstructure of the filament is substantially exclusively elongated and the Long to Wide of the Grain exceed 15. The rhenium content of the filament is between 0.4~0.8% by weight. The method for manufacturing a rhenium-tungsten comprises the following steps. An ASK doped tungsten-rhenium alloy powder is prepared with a rhenium content of 0.4~0.8% by weight. The alloy powder is pressed in the isostatic press machine and presintered. And the rhenium-tungsten alloy ingot is sintered with the direct current. The bar was forged and drawn into rhenium-tungsten wire. Then a rhenium-tungsten filament is formed, which has a metastable crystal structure and can be better used in the halogen incandescent lamps.
Description
A method for producing filament for halogen lamp
TECHNICAL FIELD OF INVENTION
The invention relates to a tungsten-rhenium filament for high temperature working condition, especially used for halogen incandescent lamps. This invention also relates to a tungsten wire which can increase the re-crystallization temperature comprising to the non-sag tungsten wire.
BACKGROUND OF INVENTION
The invention relates to a tungsten-rhenium filament for high temperature working condition, especially used for halogen incandescent lamps. This invention also relates to a tungsten wire which can increase the re-crystallization temperature comprising to the non-sag tungsten wire.
The rhenium-tungsten wire for halogen incandescent lamps can work under a high temperature and have a high re-crystallization temperature. It can be used as stage- and studio lamps, and special headlamps. The typical high operation temperature is between 2900 centigrade and 3200 centigrade and it has a long working time. It can result the traditional NS-Doped tungsten wire's short working time effectively, it but also has a large Long to Wide of the Grain and has a low sag value. On the other hand; it can improve the non-sag properties of the filaments, particularly at high temperature.
Higher filament temperature permits the use of smaller size filaments and concomitantly smaller size lamps for a given light output, which is very desirable in the market place. At the present time, the use of halogen filament at color temperature above 2800K results in substantial sag which, in turn distort the filament coil resulting in an increase in the radiant heat loss, thereby decreasing the luminous efficacy. Rhenium-tungsten wire can increase the re-crystallization temperature and strength the grain boundary structure. The amount of the rhenium added in tungsten powder is minimal and between 0.4" 0.8% by weight. It can not increase much the cost of the manufacture of the tungsten wire.
Tungsten ingots intended for making tungsten filaments also contain a very minor amount of dopants such as potassium, aluminium and silicon. In fabricating the fine rhenium-tungsten from which filaments are produced, the process cycle and the equipments are same to the traditional NS-sag tungsten wire while the process temperature, process compressibility and deformation velocity will be changed to fit for the rhenium-tungsten alloy, for the rhenium-tungsten alloy is solid solution alloy.
The effect of ASK on the traditional tungsten wire is well known for the filaments of
incandesbent lamps, but the AKS dopants can not resolve the problem of decreased re-crystallization temperature. The addition of ASK is mostly used to form the potassium bubble which can urge the interlocking grain structure. However, with the color temperature increasing, the operating temperature of the filaments has exceeded 2800K; the increased tendency of void formation on the grain boundaries is observed. The main reason of the formation of the voids is the potassium which was added in the former procedure. The rhenium-tungsten alloy is solid solution alloy. So the solid solution atoms can strength the grain structure especially the grain boundary structure which can compensates the negative effect of the potassium. It was considered that the addition of at least 0.4% by weight rhenium is necessary can make up for the void forming effect in filaments operating at high temperature.
With the amount of rhenium increasing, the grain structure and the wire's mechanical properties improve. And the little amount (as little as 0.4%) can increase the temperature for the complete re-crystallization for rhenium-tungsten filaments above the critical value of 2300-2400 centigrade during the re-crystallization. Altogether, improving the rhenium-tungsten filament initial re-crystallization temperature above the annealing temperature of the filament during the fabricating the filament is needed. The grain structure is optimum and the Long to Wide of the grain will exceed 15 while the little amount rhenium may increase the cost of the wire little and it will be more economical.
SUMMARY OF PATENT
The present invention has been made in view of the foregoing disadvantage of the prior art.
In accordance with the present invention, there is provided a filament made of a rhenium-tungsten alloy wire. The re-crystallization temperature of the wire exceeds 2200 [deg.] C. The alloy wire also include the potassium, aluminium and silicon additive. The dopants amount is between 80-100ppm. The rhenium content is of 0.4-0.8% by weight.
In accordance with the present invention, the invention includes the following fabricating processing step. The powder was prepared with the dopants ASK and the alloy element rhenium. The amount of the dopants is between 80~ 100ppm.The powder was mixed for a suitable time and pressed under 160" 200MPa according to the dimension of the ingots. The ingots were sintered with direct current. The wire was draw from the sintered alloys.
In accordance with the present invention, the solid solution atom can strengthen the grain boundary, the tensile strength increase greatly, which can decrease the wire broken in fabricating the filament and improving the productive efficiency. Rhenium has high electrical resistivity, so the rhenium-tungsten wire has higher cold resistance which can shorten the filament effective length in designing the filament, so the materials can be
saved which can compensate the cost of the added rhenium.
BRIEF DISCRIPTION OF DRAWINGS
These and other objects and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings; where in:
Fig 1 is a graphic representation showing the filament of the halogen lamp.
Fig 2 is a graphic representation showing the metallograph of the processing state of ø8.9mm.
Fig 3 is a graphic representation showing the complete re-crystallization grain structure of øδ.θmm.
Fig 4 is a graphic representation showing the grain structure of started re-crystallization.
Fig 5 is a graphic representation showing the grain structure of complete re-crystallization.
DETAILED DESCRIPTION
In the rhenium-tungsten filament, the dopants ASK (potassium, aluminium, silicon) are contained. The content of the potassium is between 80-100ppm, and it has a rhenium content of 0.4-0.8% by weight. According to technics to prepare the alloy power, the rhenium atom is well-distributed in the tungsten matrix. The amount of the potassium ensures the potassium bubble bunched during the drawing process. Rhenium can strengthen the grain boundary and improve the re-crystallization temperature. The synthetic action of potassium bubble and rhenium achieve a good grain structure and the filament also has a high initial re-crystallization temperature. The initial re-crystallization temperature will be above 2100[deg.] C. The Long to Wide of the grain can exceed 15.
Rhenium-tungsten alloy is solid solution alloy, solid solution atom strengthen the crystal lattice of tungsten; so the drawing temperature of the rhenium-tungsten wire must higher than the doped-tungsten wire, as it was explained above paragraph.
As elaborated in the last section, the tungsten wire is strengthened by the rhenium because of the solid solution strength. The start and the end re-crystallization temperature are improved greatly, while the tensile strength is improved. The representative rhenium-tungsten wire comparing to the traditional NS-doped tungsten wire characteristics are shown in the table below.
Test tungsten metal sample with 83ppm potassium content and 0.45% and 0.60% by weight rhenium-tungsten alloys were produced. Form the two samples, tungsten wires were made for the filament production. The most important characteristic of the wire at a diameter of 0.39mm were controlled and stable including high temperature strength, cracking level, starting re-crystallization temperature, Long to Wide of grain, high temperature doping value, etc. The quality of rhenium-tungsten wire is higher obviously than traditional NS-doped tungsten wire.
Fig 2 is the rhenium-tungsten alloy with 0.45% by weight after forging, the microstructure of the grain is typical process state. The grain is uniform which provide an excellent structure for the annealing and the following forging. In this process the temperature and deformation rate must be controlled, or much crack will be produced. The average deformation ratio is about 25" 30%. The value is adjusted according to the actual condition.
Fig 3 is the rhenium-tungsten alloy after complete annealing. The process homogenization determines the re-crystallization structure and the potassium bubble deformation. It is also the determining factor for the following process. The propose of this process can eliminate the cold hardening and fine the grains.
The starting point of the re-crystallization temperature of the rhenium-tungsten wire at a diameter of 0.39mm is 2250 "C . Because thermal radiation, the core of the wire temperature is higher than the surface, re-crystallization begin with the core of the wire. After the complete re-crystallization, fig 5 illustrates the elongated interlocking grain structure. The Long to Wide of Grain exceed 15 which assure the high temperature property of the wire. The excellent grain structure determines the filament with a lower sagged value which can increase greatly the filament life.
As elaborated preamble, rhenium can strengthen the grain boundary structure. The voids on the grain boundaries can be avoided greatly, so during the using of the filament there are few hot pots appearance. For the other hand, the rhenium-tungsten filament has the lower dropped value comparing to the traditional AKS NS-tungsten filament, the filament screw-pitch is very well-distributed during the using process which can bring the well-distributed temperature of the filament. Because of the virtues of the filament, the tungsten evaporation is well-distributed, so few hot pots appear. The life time of the filament can be increased largely.
The rhenium-tungsten filament which recommended is applicable for all type of lamps, and it is especially used for tungsten halogen lamps. The application of this filament will largely increase the life time of the lamps and reduce the breakage of finished lamps
during handling and shipping.
The invention is not limited to the showed and disclosed embodiments, but other elements, improvements and variations are also within the scope of the invention.
INDUSTRIAL APPLICABILITY
As elaborated in the last section, the tungsten wire is strengthened by the rhenium because of the solid solution strength. The start and the end re-crystallization temperature are improved greatly, while the tensile strength is improved. The representative rhenium-tungsten wire comparing to the traditional NS-doped tungsten wire characteristics are shown in the table below.
Claims
1. A filament for halogen lamp made of a rhenium-tungsten alloy wire. The wire material has a re-crystallization temperature above 2100°C, the wire material including an AKS (aluminium, potassium, silicon) additive, the wire material having a potassium content between 80" 100 ppm, and having a rhenium content of 0.4" 0.8% by weight.
2. The filament of claim 1 in which the rhenium content is 0.4" 0.8% by weight.
3. The filament of claim 1 in which the potassium content in the wire material is between 80" 100ppm.
4. The filament of claim I in which the rhenium is uniformly distributed in the tungsten matrix.
5. The filament of claim 1 in which the least weight rhenium-tungsten wire weight by length of 200mm is 1mg.
6. The filament of claim 1 in which the wire material comprising less than 10 ppm silicon.
7. The filament of claim 1 in which the wire material comprising less than 10 ppm aluminium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2006/001390 WO2008009154A1 (en) | 2006-06-20 | 2006-06-20 | A method for producing filament for halogen lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2006/001390 WO2008009154A1 (en) | 2006-06-20 | 2006-06-20 | A method for producing filament for halogen lamp |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2008009154A1 true WO2008009154A1 (en) | 2008-01-24 |
Family
ID=38956499
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/CN2006/001390 WO2008009154A1 (en) | 2006-06-20 | 2006-06-20 | A method for producing filament for halogen lamp |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2008009154A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010103431A1 (en) * | 2009-03-10 | 2010-09-16 | Koninklijke Philips Electronics N. V. | Halogen lamp for pulse operation |
| WO2012037982A1 (en) | 2010-09-24 | 2012-03-29 | Osram Gesellschaft mit beschränkter Haftung | Luminous element for halogen light bulb and associated halogen light bulb |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6597107B1 (en) * | 2002-01-11 | 2003-07-22 | General Electric Company | Tungsten-rhenium filament and method for producing same |
| US6624577B2 (en) * | 2001-03-19 | 2003-09-23 | General Electric Company | Tungsten-rhenium filament and method for producing same |
| JP2005032552A (en) * | 2003-07-14 | 2005-02-03 | Ushio Inc | Heater lamp for heat source |
| US20050155680A1 (en) * | 2004-01-16 | 2005-07-21 | Gyorgy Nagy | High ductility, high hot tensile strength tungsten wire and method of manufacture |
-
2006
- 2006-06-20 WO PCT/CN2006/001390 patent/WO2008009154A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6624577B2 (en) * | 2001-03-19 | 2003-09-23 | General Electric Company | Tungsten-rhenium filament and method for producing same |
| US6597107B1 (en) * | 2002-01-11 | 2003-07-22 | General Electric Company | Tungsten-rhenium filament and method for producing same |
| JP2005032552A (en) * | 2003-07-14 | 2005-02-03 | Ushio Inc | Heater lamp for heat source |
| US20050155680A1 (en) * | 2004-01-16 | 2005-07-21 | Gyorgy Nagy | High ductility, high hot tensile strength tungsten wire and method of manufacture |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010103431A1 (en) * | 2009-03-10 | 2010-09-16 | Koninklijke Philips Electronics N. V. | Halogen lamp for pulse operation |
| CN102349130A (en) * | 2009-03-10 | 2012-02-08 | 皇家飞利浦电子股份有限公司 | Halogen lamp for pulse operation |
| WO2012037982A1 (en) | 2010-09-24 | 2012-03-29 | Osram Gesellschaft mit beschränkter Haftung | Luminous element for halogen light bulb and associated halogen light bulb |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110106418B (en) | Rare earth molybdenum tungsten alloy for cutting wire and preparation method thereof | |
| JP5848259B2 (en) | Manufacturing method of brake piston shape material | |
| JP4916264B2 (en) | Electrodes for fusing welding | |
| WO2010100808A1 (en) | Rhenium-tungsten wire, process for producing same, and medical needle comprising same | |
| CN101083202A (en) | Halogen filament and process for manufacturing the same | |
| US6624577B2 (en) | Tungsten-rhenium filament and method for producing same | |
| JP4426904B2 (en) | Tungsten wire and method for manufacturing the same | |
| EP1555331B1 (en) | High ductility, high hot tensile strength tungsten wire and method of manufacture | |
| WO2008009154A1 (en) | A method for producing filament for halogen lamp | |
| EP1335410B1 (en) | Tungsten-rhenium filament and method for producing same | |
| JP4886199B2 (en) | Method for producing high-temperature stable niobium wire | |
| JP5611589B2 (en) | Method for manufacturing filament cathode member for magnetron and filament cathode member for magnetron | |
| CN101243539B (en) | Wire and frame in particular niobium-based for single-side socket lamps and a method for the production and use thereof | |
| JP2001152275A (en) | Wire filament for cathode for x-ray tube | |
| JP5086503B2 (en) | Method for manufacturing thorium tungsten wire | |
| CN115992329B (en) | Tungsten rod blank and application thereof | |
| CN108588531B (en) | A kind of anode material and preparation method thereof | |
| US3136039A (en) | Tungsten alloy | |
| US6190466B1 (en) | Non-sag tungsten wire | |
| JP4144184B2 (en) | Manufacturing method of heat-resistant Al alloy wire for electric conduction | |
| US20230243019A1 (en) | Copper alloy, plastically worked copper alloy material, component for electronic/electrical equipment, terminal, heat dissipation substrate | |
| JP4256126B2 (en) | Tungsten-rhenium material and method for producing the same, cathode heater for cathode ray tube made of this tungsten-rhenium material, tube filament, and probe pin for electrical property inspection | |
| JPH03219039A (en) | Rhenium-tungsten alloy material excellent in workability and its manufacture | |
| JPH0222133B2 (en) | ||
| Gahn et al. | The Potassium Secret Behind Modern Tungsten Wire Production |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 06761305 Country of ref document: EP Kind code of ref document: A1 |
|
| NENP | Non-entry into the national phase |
Ref country code: DE |
|
| NENP | Non-entry into the national phase |
Ref country code: RU |
|
| 122 | Ep: pct application non-entry in european phase |
Ref document number: 06761305 Country of ref document: EP Kind code of ref document: A1 |