EP1246220A1 - Lead-in wire - Google Patents
Lead-in wire Download PDFInfo
- Publication number
- EP1246220A1 EP1246220A1 EP01201154A EP01201154A EP1246220A1 EP 1246220 A1 EP1246220 A1 EP 1246220A1 EP 01201154 A EP01201154 A EP 01201154A EP 01201154 A EP01201154 A EP 01201154A EP 1246220 A1 EP1246220 A1 EP 1246220A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- nickel
- wire
- lead
- iron
- coating layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01K—ELECTRIC INCANDESCENT LAMPS
- H01K1/00—Details
- H01K1/40—Leading-in conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
- H01J5/46—Leading-in conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/36—Seals between parts of vessels; Seals for leading-in conductors; Leading-in conductors
Definitions
- the invention relates to a lead-in wire for use in lamps and electron tubes and to lamps and electron tubes comprising such a lead-in wire.
- the invention further relates to a method for the manufacturing of lead-in wires.
- the inner lead-in wire of a lamp which is the part of the lead-in wire extending from a stem of glass upwardly inside the glass envelope, is generally made of nickel because its high melting point. Also wires made of a nickel alloy such as an alloy consisting of 98 wt% Ni and 2 wt% Mn, wires of an nickel-iron alloy or nickel plated steel wires are known in the art.
- the lead-in wires made of a substitute material should meet the necessary quality requirements
- a lead-in wire is provided.
- the lead-in wire is in particular suitable as inner lead-in wire of a lamp or electron tube.
- the lead-in wire according to the present invention comprises a steel core surrounded by a coating layer comprising a nickel-iron (NiFe) alloy.
- the coating layer comprising the nickel-iron alloy has a thickness higher than 0.1 ⁇ m, for example between 0.2 and 10 ⁇ m. It is particularly advantageous that the coating layer has a thickness between 1 and 5 ⁇ m, for example between 1.5 and 2.5 ⁇ m.
- the nickel-iron layer has an iron content of at least 1 wt%.
- the iron content is higher than 30 wt% and more preferably higher than 40 wt%, for example 50 wt%.
- the Ni content of the coating layer is higher than 1 wt%.
- the content of Ni is higher than 30 wt%, and more preferably higher than 400 wt%, for example 50 wt%.
- a preferred coating composition comprises between 30 and 70 wt% Ni and between 30 and 70 wt% Fe. More preferably the coating comprises between 50 and 60 wt% Ni and between 40 and 50 wt% Fe.
- the presence of iron in the coating layer can be due to diffusion of iron, for example of the steel, into the coating layer or may be due to the presence of iron salts during the application of the coating layer.
- a gradient of the iron or nickel content over the thickness of the coating can be observed.
- the concentration of nickel increases towards the outer surface of the coating layer.
- the steel core may have any cross-section, such as cirular, oval-shaped or rectangular cross-sections.
- Preferred cores have a circular cross-section and a diameter ranging between 0.2 and 2 mm, for example 0.35 or 0.50 mm.
- the steel core is typically made of low carbon steel, although other metal wires may also be employed.
- the lead-in wires according to the present invention are suitable to be used for illumination lamps and electron tubes.
- Illumination lamps are considered to include incandescent lamps, gas discharge lamps, flash lamps and the like.
- a method of manufacturing a lead-in wire according to the present invention comprises the steps of
- Any coating technique that results in obtaining a coating layer according to this invention can be considered.
- Such techniques are for example hot dip, vapour deposition, chemical plating, melt plating, melt spraying and electroplating.
- the nickel-iron alloy can be formed by applying a nickel coating on the steel core and by subjecting the coated wire to a heat treatment, whereby the temperature is at least 400 °C to form a nickel-iron alloy.
- the nickel-iron coating layer is formed by applying a coating layer comprising nickel and iron to the steel core.
- the coated wire is subjected to a heat treatment in a subsequent step.
- the method for the application of the coating layer may comprise the application of a mixture of nickel and iron. Possibly the application of the coating layer is followed by a heat treatment.
- an illumination lamp or electron tube comprising a lead-in wire according to the present invention is provided.
- a lead-in wire according to the present invention is manufactured as follows : A steel wire is drawn to a determined diameter, e.g. to a diameter of 0.35 mm. In a first step a nickel coating layer is applied on a low carbon steel wire. For the application of the nickel layer the following parameters may be used:
- the thickness of the applied nickel coating is for example 0.8 ⁇ m.
- the coated wire is subjected to a heat treatment, for example at a temperature higher than 400 °C.
- a heat treatment for example at a temperature higher than 400 °C.
- the thickness of this nickel-iron alloy is for example 1.6 ⁇ m.
- An alternative method comprises the electrolytic application of a nickel-iron alloy by using a plating bath comprising iron salts and nickel salts.
- the nickel-iron coating forms a closed layer characterised by a low porosity .
- the coating has a high ductility so that the coated wire can be rolled or bent. Furthermore, the nickel-iron coating layer is giving the steel wire a good corrosion protection at high temperatures.
- the lamp comprises a light-transmitting, glass envelope 12 secured to a base member 14.
- Lead-in wires 15 generally comprise three segments of different materials. More particularly, lead wires comprise an inner lead-in wire 16, an intermediate wire 17 and an outer lead-in wire 18. The different segments of the lead-in wire are soldered or welded, for example buttwelded.
- the intermediate wire is positioned in a stem of pressed glass. The upper portion of the stem is inserted into the glass envelope of the lamp. The portion of the lead-in wire extending upwardly from the stem constitute the inner lead-in wire, while the portions of the lead-in wires extending downwardly from the stem constitute the outer lead-in wire.
- the intermediate wire is preferably a dumet wire.
- a dumet wire has a nickel-iron core coated with a copper layer.
- the inner lead-in wire comprises a wire according to the present invention.
- a coiled filament 20, which is generally a tungsten filament is clamped by the ends of the two inner lead-in wires. Therefore, the inner lead-in wires are at one end rolled and bent, for example over 180°. This rolling and bending imposes high requirements such as a good ductility on the lead-in wires.
- the nickel-iron alloy coating of the lead-in wire according to the present invention does meet this requirement.
Abstract
The invention relates to a lead-in wire comprising a steel core
surrounded by a nickel-iron alloy. Also a method of manufacturing a
lead-in wire is described.
Description
- The invention relates to a lead-in wire for use in lamps and electron tubes and to lamps and electron tubes comprising such a lead-in wire. The invention further relates to a method for the manufacturing of lead-in wires.
- The inner lead-in wire of a lamp, which is the part of the lead-in wire extending from a stem of glass upwardly inside the glass envelope, is generally made of nickel because its high melting point.
Also wires made of a nickel alloy such as an alloy consisting of 98 wt% Ni and 2 wt% Mn, wires of an nickel-iron alloy or nickel plated steel wires are known in the art. - Since nickel is a rather expensive metal it is desirable to replace the nickel by a cheaper material.
However, the lead-in wires made of a substitute material should meet the necessary quality requirements - It is an object of the present invention to provide a lead-in wire that can be manufactured at low costs.
It is another object to provide a lead-in wire with a high corrosion protection at high temperatures.
It is a further object to provide a lead-in wire with a high ductility. - According to a first aspect of the present invention, a lead-in wire is provided. The lead-in wire is in particular suitable as inner lead-in wire of a lamp or electron tube.
The lead-in wire according to the present invention comprises a steel core surrounded by a coating layer comprising a nickel-iron (NiFe) alloy. - Preferably, the coating layer comprising the nickel-iron alloy has a thickness higher than 0.1 µm, for example between 0.2 and 10 µm. It is particularly advantageous that the coating layer has a thickness between 1 and 5 µm, for example between 1.5 and 2.5 µm.
- The nickel-iron layer has an iron content of at least 1 wt%. Preferably, the iron content is higher than 30 wt% and more preferably higher than 40 wt%, for example 50 wt%.
The Ni content of the coating layer is higher than 1 wt%. Preferably, the content of Ni is higher than 30 wt%, and more preferably higher than 400 wt%, for example 50 wt%. - A preferred coating composition comprises between 30 and 70 wt% Ni and between 30 and 70 wt% Fe. More preferably the coating comprises between 50 and 60 wt% Ni and between 40 and 50 wt% Fe.
- The presence of iron in the coating layer can be due to diffusion of iron, for example of the steel, into the coating layer or may be due to the presence of iron salts during the application of the coating layer.
- Possibly, a gradient of the iron or nickel content over the thickness of the coating can be observed.
In a preferred embodiment the concentration of nickel increases towards the outer surface of the coating layer. - The steel core may have any cross-section, such as cirular, oval-shaped or rectangular cross-sections.
Preferred cores have a circular cross-section and a diameter ranging between 0.2 and 2 mm, for example 0.35 or 0.50 mm. - The steel core is typically made of low carbon steel, although other metal wires may also be employed.
- The lead-in wires according to the present invention are suitable to be used for illumination lamps and electron tubes.
Illumination lamps are considered to include incandescent lamps, gas discharge lamps, flash lamps and the like. - According to a second aspect a method of manufacturing a lead-in wire according to the present invention is provided :
The method comprises the steps of - providing a steel core;
- forming a coating layer comprising a nickel-iron alloy on said steel core.
- Any coating technique that results in obtaining a coating layer according to this invention can be considered. Such techniques are for example hot dip, vapour deposition, chemical plating, melt plating, melt spraying and electroplating.
- The nickel-iron alloy can be formed by applying a nickel coating on the steel core and by subjecting the coated wire to a heat treatment, whereby the temperature is at least 400 °C to form a nickel-iron alloy.
- Alternatively, the nickel-iron coating layer is formed by applying a coating layer comprising nickel and iron to the steel core. Possibly, the coated wire is subjected to a heat treatment in a subsequent step.
- The method for the application of the coating layer may comprise the application of a mixture of nickel and iron. Possibly the application of the coating layer is followed by a heat treatment.
- According to a further aspect an illumination lamp or electron tube comprising a lead-in wire according to the present invention is provided.
- The invention will be described into more detail with reference to the accompanying drawings wherein
- FIGURE 1 is a cross-section of a lamp comprising a lead-in wire according to the present invention.
- A lead-in wire according to the present invention is manufactured as follows :
A steel wire is drawn to a determined diameter, e.g. to a diameter of 0.35 mm.
In a first step a nickel coating layer is applied on a low carbon steel wire. For the application of the nickel layer the following parameters may be used: - bath composition:
- NiSO4.6H2O :
- 225 - 410 g/L
- NiCl2.6H2O :
- 30 - 100 g/L
- H3BO3 :
- 25 - 40 g/L
- pH : 1.5-5.2
- Temperature : 45 - 70°C
- Current density : 1 - 20 A/dm2
- Other suitable baths comprise for example Ni-sulfamate.
- The thickness of the applied nickel coating is for example 0.8 µm.
- After the application of the nickel coating, the coated wire is subjected to a heat treatment, for example at a temperature higher than 400 °C.
By this heat treatment a nickel-iron alloy is formed. The thickness of this nickel-iron alloy is for example 1.6 µm. - An alternative method comprises the electrolytic application of a nickel-iron alloy by using a plating bath comprising iron salts and nickel salts.
- The nickel-iron coating forms a closed layer characterised by a low porosity . The coating has a high ductility so that the coated wire can be rolled or bent.
Furthermore, the nickel-iron coating layer is giving the steel wire a good corrosion protection at high temperatures. - Referring to Figure 1, the cross-section of a
lamp 10 is shown. The lamp comprises a light-transmitting,glass envelope 12 secured to abase member 14. - Lead-in
wires 15 generally comprise three segments of different materials.
More particularly, lead wires comprise an inner lead-inwire 16, anintermediate wire 17 and an outer lead-inwire 18. The different segments of the lead-in wire are soldered or welded, for example buttwelded.
The intermediate wire is positioned in a stem of pressed glass.
The upper portion of the stem is inserted into the glass envelope of the lamp. The portion of the lead-in wire extending upwardly from the stem constitute the inner lead-in wire, while the portions of the lead-in wires extending downwardly from the stem constitute the outer lead-in wire.
The intermediate wire is preferably a dumet wire. A dumet wire has a nickel-iron core coated with a copper layer.
The inner lead-in wire comprises a wire according to the present invention.
A coiledfilament 20, which is generally a tungsten filament is clamped by the ends of the two inner lead-in wires. Therefore, the inner lead-in wires are at one end rolled and bent, for example over 180°.
This rolling and bending imposes high requirements such as a good ductility on the lead-in wires. The nickel-iron alloy coating of the lead-in wire according to the present invention does meet this requirement.
Claims (7)
- Lead-in wire comprising a steel core, said steel core being surrounded by a coating layer comprising a nickel-iron alloy.
- Lead-in wire according to claim 1, whereby said layer has a thickness between 1 and 10 µm.
- Lead-in wire according to any one of the preceding claims, whereby said nickel-iron alloy has a nickel content between 30 and 70 wt% and an iron content between 30 and 70 wt%.
- A method of manufacturing a lead-in wire according to any one of claims 1 to 3, said method comprising the steps ofproviding a steel core;forming a coating layer comprising a nickel-iron alloy on said steel core.
- A method according to claim 4, whereby said coating layer comprising a nickel-iron alloy is formed byapplying a nickel coating on said steel core;subjecting the coated wire to a heat treatment, whereby the temperature is at least 400 °C to form a nickel-iron alloy.
- A method according to claim 4, whereby said coating layer comprising a nickel-iron alloy is formed byapplying a coating layer comprising nickel and iron to said steel core.
- Lamp or electron tube comprising at least one lead-in wire according to any one of claims 1 to 3.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP01201154A EP1246220A1 (en) | 2001-03-26 | 2001-03-26 | Lead-in wire |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP01201154A EP1246220A1 (en) | 2001-03-26 | 2001-03-26 | Lead-in wire |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1246220A1 true EP1246220A1 (en) | 2002-10-02 |
Family
ID=8180078
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP01201154A Withdrawn EP1246220A1 (en) | 2001-03-26 | 2001-03-26 | Lead-in wire |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP1246220A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102315077A (en) * | 2010-05-25 | 2012-01-11 | 通用电气公司 | Has the band coating inner wire to improve the low-pressure discharge lamp of lumen depreciation |
CN107134397A (en) * | 2016-02-29 | 2017-09-05 | 斯坦雷电气株式会社 | Incandescent lamp |
CN108987244A (en) * | 2017-06-02 | 2018-12-11 | 东芝照明技术株式会社 | Lead, the manufacturing method of lead and motor-vehicle bulb |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05320842A (en) * | 1992-05-25 | 1993-12-07 | Tokin Corp | Production of material for reed switch |
EP0923109A1 (en) * | 1997-12-10 | 1999-06-16 | Firma Bruno Dietze | Low voltage halogen lamp with pin socket and current lead-in conductor |
-
2001
- 2001-03-26 EP EP01201154A patent/EP1246220A1/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05320842A (en) * | 1992-05-25 | 1993-12-07 | Tokin Corp | Production of material for reed switch |
EP0923109A1 (en) * | 1997-12-10 | 1999-06-16 | Firma Bruno Dietze | Low voltage halogen lamp with pin socket and current lead-in conductor |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 018, no. 145 (C - 1178) 10 March 1994 (1994-03-10) * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102315077A (en) * | 2010-05-25 | 2012-01-11 | 通用电气公司 | Has the band coating inner wire to improve the low-pressure discharge lamp of lumen depreciation |
CN107134397A (en) * | 2016-02-29 | 2017-09-05 | 斯坦雷电气株式会社 | Incandescent lamp |
CN108987244A (en) * | 2017-06-02 | 2018-12-11 | 东芝照明技术株式会社 | Lead, the manufacturing method of lead and motor-vehicle bulb |
CN108987244B (en) * | 2017-06-02 | 2022-03-29 | 东芝照明技术株式会社 | Lead wire, method for manufacturing lead wire, and bulb for vehicle |
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