Method for reducing molybdenum oxidation in lamps
AssigneeGeneral Electric Company
InventorsThomas G. Parham, Michael E. Hanson
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Abstract
Electric lamps having molybdenum metal parts exposed to an oxidizing environment can withstand exposure to higher operating temperature if the molybdenum metal parts are coated with silicon nitride (Si.sub.3 N.sub.4). Tungsten-halogen lamps having molybdenum outer leads coated with silicon nitride have operated for over 1500 hours at about 450.degree. C. without oxidation failure of the leads.
Claims16
An electric lamp comprising a vitreous envelope having at least one metal outer lead construction hermetically sealed in at least one end thereof wherein said outer lead construction comprises molybdenum hermetically sealed into said vitreous envelope and wherein said molybdenum is coated with silicon nitride.
An electric lamp comprising a vitreous envelope having at least one molybdenum lead construction hermetically sealed in said envelope, wherein the outer portion of said lead is exposed to an oxidizing environment at temperatures of at least 350.degree. C. during operation of said lamp and wherein said outer surface of said molybdenum lead is coated with silicon nitride.
The lamp of claim 16 wherein said vitreous envelope comprises a high temperature glass composition.
A method of coating a molybdenum lead for an electric lamp comprising exposing said lead to vaporized SiCl.sub.4 and NH.sub.3.
A method of coating a molybdenum lead for an electric lamp comprising exposing said lead to vaporized SiH.sub.2 Cl.sub.2 and NH.sub.3.
Dependencies are inferred from the claim text.