Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
  • C23C2/10—Lead or alloys based thereon
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
  • H01B1/026—Alloys based on copper
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B7/00—Insulated conductors or cables characterised by their form
  • H01B7/04—Flexible cables, conductors, or cords, e.g. trailing cables
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12687—Pb- and Sn-base components: alternative to or next to each other
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12701—Pb-base component

Definitions

• the present invention relates to an insulated multi-wire electric cable with protected conductors, weldable and non-fusible.
• Some cables for aeronautics consist of electrical conductor strands or strands protected by a metallic coating, and insulated either by a sheath of thermoplastic polymer, or by a polyimide taping, taping which can be covered by a sheath of thermoplastic polymer.
• the protected electrical conductors of these known cables are copper wires traditionally covered either with tin, or with silver, or with nickel.
• This heat sealing is due to the fact that the melting point of the tin is 232 ° C.
• the wires protected with nickel have the drawback of not being weldable and oblige the user to carry out crimping operations or chemical pickling of the nickel when making connections.
• Silver-protected wires are well suited, but they have the disadvantage of being expensive on the one hand, and on the other hand protection against electrochemical corrosion of copper is not ensured since silver does not realize cathodic protection.
• Lead alloys such as that with 30% tin and 70% lead have the drawback of no longer being weldable after accelerated aging treatments of 96 hours in air and at a temperature of 155 ° C. or 4 hours at 100 ° C in water vapor, according to the tests described in French standard NFC 20630 paragraph 2.5.
• the loss of weldability is due in particular to a diffusion of copper in the alloy layer which leads to the formation of an intermetallic compound of Cu 3 Sn type which cannot be welded.
• Alloys of the lead-silver type have the drawback of being sensitive to atmospheric humidity during prolonged storage, which results in a complete loss of weldability.
• the wettability at a temperature of the order of 350 ° C. of the alloy is excellent, otherwise the metallic coatings are eccentric and the weldability or solder is defective, the covering of the electrical conductor by the alloy taking place. by the hot dipping process, at a temperature of the order of 350 ° C.
• a tin alloy with a high lead content is already known and described in document DE-C-813622 as a means of protection against oxidation of an electrical conductor in bare or insulated copper.
• an alloy comprising 92 to 97% of lead, 3 to 8% of tin and 0.3 to 0.6% of antimony makes it possible to protect against oxidation, an electrical conductor in copper working at a high temperature of the order of 275 to 300 ° C.
• the aim of the present invention is to produce an economical multi-wire cable with non-fusible electrical conductors remaining individually separated even after an operation of electrical insulation of their twist and having good protection. cathodic, and good weldability even after accelerated aging such as one of the aging described in French standard NFC 20630.
• Such a multi-wire electric cable is the subject of the first three claims appended hereto.
• the indicated percentages of the metallic constituents of the alloys described and claimed in the context of the invention are percentages by weight.
• an intermetallic layer is not formed between the conductor and the alloy after accelerated aging of this conductor.
• the good wettability characteristics of the alloy coating the conductors of the cable of the invention make it possible to advantageously use the hot dipping process for the coating of these conductors.
• the hot dipping process provides highly adherent coatings which guarantee good welding or soldering even in the case of automatic welding.
• This process also makes it possible to obtain non-porous, very compact coatings which ensure good protection against oxidation in the event of prolonged storage as well as good weldability after accelerated aging.
• Such coatings produced in accordance with the invention provide good protection of the cable conductors against corrosion even in the case where a lead-silver alloy is used. This seems surprising, since lead-silver alloys mentioned in a previous paragraph are reputed to be sensitive to humidity.
• the coatings of the conductors of the cable produced according to the invention also make it possible to avoid bonding of these conductors during the operation of insulating their twist, for example, by extruding a thermoplastic or thermosetting sheath or else sealing the tape. , operations taking place at temperatures of 300-350 ° C. This seems surprising since it was recognized that these coatings had to have a melting point above 400 ° C to avoid any melting or softening which would cause bonding between the conductors of the tordon, which explains why the silver and incidentally the nickel are generally used as protective metals for these conductors.
• the coating thickness of these conductors is between one and ten microns and preferably between one and five microns.
• the method of coating the copper wire is according to the invention, the method of dipping in a bath of molten alloy.
• An annealed copper wire with a diameter of 0.20 mm is firstly cleaned by passing over felts soaked in trichloroethane III, volatile solvent, with a boiling point of 74 ° C.
• the dry wire then passes over felts soaked in an etching-pickling liquid composed of a solution of 1N hydrochloric acid, ie one gram molecule of acid per liter.
• the wire is then passed through a 350 ° C bath of molten lead-silver alloy Pb Ag 3, 97.5% lead and 2.5% silver for 100% alloy.
• a diamond die used for the drawing of copper wires, is placed just at the exit of the bath; it allows the alloy deposit to be calibrated to obtain a thickness of 3 microns.
• the internal diameter of the die is 0.208 0 mm.
• the drop weldability of the wire thus protected, measured in accordance with French standard NFC 20630 paragraph 2.8 is 0.3 seconds at 235 ° C.
• the weldability in an alloy bath of the wire protected according to paragraph 2.6 of the French standard NFC 20630 is good at 235 ° C.
• the drop weldability of the protected wire measured after the accelerated aging of 16 hours at 155 ° C according to paragraph 2.53 of the French standard NFC 20630 is 1 second at 235 ° C.
• 19 protected wires of this type are assembled to obtain a 19 x 0.20 mm twist.
• the twist obtained is isolated by a double crossover taping with a polyimide tape coated with fluoroethylenepropylene for example sold under the brand KAPTON SG 16 of width 1/4 inch or 6.35 mm, by the firm DUPONT de NEMOURS.
• the overlap of the ribbons is 51%.
• the ribbon tape is finally brought for sealing in an oven whose temperature is adjusted to 320-330 ° C to obtain the cable of the invention.
• the thickness of the coating alloy layer of this wire is 5 microns.
• the temperature of the molten alloy bath for the dip coating of this wire is 350 ° C.
• the diameter of the die used for the calibration of this coating is 0.21 20 mm.
• the drop weldability of the wire thus protected is 0.2 seconds at 235 ° C.
• the weldability in an alloy bath of the wire protected according to French standard NFC 20630 paragraph 2.8 is good at 235 ° C.
• the weldability of the protected wire in an alloy bath after accelerated aging for 4 hours in boiling water paragraph 2.51 of the French standard NFC 20630 is good at 235 ° C.
• Double taping of this twist is carried out with a ribbon of the same type as that of Example 1.
• the sealing of the tords of the twist obtained is carried out by passage through an oven at a temperature of 320-330 ° C.
• the taped and sealed twist then passes ten times in succession through a bath of polyimide varnish sold, for example, under the brand Liquid H by the firm DUPONT de NEMOURS. After each coating by passage through the varnish bath, this twist passes through an oven at a temperature of 400 ° C.
• the extra thickness of insulation from the varnish after drying and firing is 80 microns in diameter.
• a copper wire protected by a Pb Sn 8 alloy consisting of 92% lead, 8% tin, for 100% alloy is produced under conditions similar to those of Example 1.
• the thickness of the coating alloy layer of this wire is 1 micron.
• the die used for the calibration of this coating has a diameter of 0.203 2 mm.
• the temperature of the molten alloy bath for a dip coating of this wire is 350 ° C.
• the drop weldability of the wire thus protected measured according to French standard NFC 20630 is 0.3 seconds at 235 ° C.
• the weldability in an alloy bath of this protected wire is good and the weldability of the latter with a drop after aging for 4 hours in boiling water is 1 second at 325 ° C.
• 19 protected wires of this type are assembled to obtain a 19 x 0.20 mm twist.
• the twist then passes through an extruder supplied with ethylene tetrafluoroethylene marketed for example under the brand TEFZEL 200 by the firm DUPONT de NEMOURS, at a temperature of about 330 ° C.
• the thickness of the coating deposited is 0.2 mm.
• the strands of the twist are not glued together, and that the weldability of the twist takes place at 235 ° C. with a tin-lead filler alloy 60/40, in less than a second.
• the thickness of the deposited coating layer is 5 microns.
• the die used for the calibration of this coating is 0.212 0 mm.
• the temperature of the bath of the molten alloy for a dip coating of this wire is 350 ° C.
• the drop weldability of the wire thus protected measured according to French standard NFC 20630 is 0.2 seconds at 235 ° C.
• the weldability of this protected wire in an alloy bath is good at 235 ° C.
• the weldability of the latter after aging for 16 hours at 155 ° C. is also good.
• 19 protected wires of this type are assembled to obtain a 19 x 0.20 mm twist.
• This twist is covered by a double taping like that described in Example 1.
• the coating technique is the same as that described in Example 2.
• Drying and cooking are also done at a temperature of 400 ° C.
• FEP fluoroethylene propylene polymer

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Insulated Conductors (AREA)
• Coating With Molten Metal (AREA)

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• 1979
  • 1979-12-18 FR FR7930938A patent/FR2472252A1/fr active Granted
• 1980
  • 1980-11-21 EP EP80401676A patent/EP0032326B1/fr not_active Expired
  • 1980-11-21 DE DE8080401676T patent/DE3070560D1/de not_active Expired
• 1982
  • 1982-11-10 US US06/440,524 patent/US4524241A/en not_active Expired - Fee Related

Patent Citations (3)

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