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US 5,148,080 AGranted
Incandescent lamp filament incorporating hafnium
AssigneeHilux Development
InventorRay J. Van Thyne
Life of this patent
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Abstract
The lamp filament has a substoichiometric nitrided surface layer containing hafnium or hafnium alloy which exhibits higher emissivity in the visible light spectrum. The filament is made by providing a metallic wire containing hafnium, shaping the wire into a filament and then reacting the filament in an atmosphere containing hydrogen.
Claims27
An incandescent lamp filament having a substoichiometric nitrided surface layer containing at least about 20% by weight hafnium exhibiting an emissivity in the visible light spectrum substantially higher than that of tungsten.
Dependencies are inferred from the claim text.