Mandrel and method of manufacturing same
AssigneeGTE Laboratories Incorporated
InventorsJames J. Auborn, Elizabeth Ann Trickett
Life of this patent
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Abstract
A mandrel and a method for its manufacture and its use in manufacturing filament coils for electric lamps is disclosed. The mandrel, having a base core containing iron, is protected from diffusion of iron into a filament wire wound thereabout by a first coating of copper and a second coating of tungsten over the first, base metal. The process of coating the tungsten over the copper coating is improved by employing small amounts of copper ion contaminant in the electroplating solution. After a filament wire is wound around and annealed over this mandrel, the mandrel is selectively dissolved leaving the shaped filament coil, substantially free of extraneous metal impurities.
Claims15
A process which comprises directly electrodepositing tungsten onto a copper substrate metal, from a tungsten electrodeposition solution contaminated with from about 0.1 to about 0.3 gms/l of copper ion.
A process for making mandrels useful for making filaments for incandescent lamps comprising the step of directly electrodepositing tungsten onto a copper substrate metal from a tungsten electrodeposition solution contaminated with from about 0.1 to about 0.3 gms/l of copper ion.
A process of making incandescent lamp filaments comprising the steps of directly electroplating a tungsten electrodeposition solution contaminated with from about 0.1 to about 0.3 gms/1 of copper ion, winding filament wire around the tungsten coating, annealing the filament wire winding, and selectively dissolving the tungsten coated copper substrate metal from the filament wire.
Dependencies are inferred from the claim text.