Process of making a non-sag tungsten wire for electric lamps

To dope ammonium paratungstate with potassium, essentially devoid of silicon and ammonium, an aqueous potassium containing solution, preferably potassium hydroxide is added to an aqueous solution of ammonium paratungstate (APW), in a mol relationship of potassium to ammonium of between 0.1 and 10. A...

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Bibliographic Details
Main Authors ZIEMER; BURKHARD, SALMEN; MICHAEL, FUCHS; JOACHIM, LUNK; HANS-JOACHIM, FAIT; MARTIN, GAHN; ALFRED-GEORG
Format Patent
LanguageEnglish
Published 28.07.1998
Edition6
Subjects
BASIC ELECTRIC ELEMENTS
CASTING
CHEMISTRY
COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F
ELECTRIC INCANDESCENT LAMPS
ELECTRICITY
FERROUS OR NON-FERROUS ALLOYS
INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OFSOLID INORGANIC COMPOUNDS
INORGANIC CHEMISTRY
MAKING METALLIC POWDER
MANUFACTURE OF ARTICLES FROM METALLIC POWDER
METALLURGY
PERFORMING OPERATIONS
POWDER METALLURGY
PRETREATMENT OF RAW MATERIALS
PRODUCTION AND REFINING OF METALS
TRANSPORTING
TREATMENT OF ALLOYS OR NON-FERROUS METALS
WORKING METALLIC POWDER
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Summary:To dope ammonium paratungstate with potassium, essentially devoid of silicon and ammonium, an aqueous potassium containing solution, preferably potassium hydroxide is added to an aqueous solution of ammonium paratungstate (APW), in a mol relationship of potassium to ammonium of between 0.1 and 10. A doped ammonium potassium paratungstate (AKPW) is obtained. This ammonium potassium paratungstate is then converted to tungsten blue oxide, which is reduced, preferably in a hydrogen containing atmosphere and a tungsten powder is then obtained which will be doped with 40 to 120 ppm, preferably about 90 ppm of potassium. Lamps equipped with tungsten wire filaments drawn from so doped tungsten have lifetimes at least 10% more than lamps with conventional tungsten filaments.
Bibliography:Application Number: US19960608550