Determination of phosphorus in gold or silver brazing alloys
A spectrophotometric method was devised for measuring microgram levels of phosphorus in brazing alloys of gold or silver that contain high nickel concentrations. Phosphorus in such alloys is normally measured by solid mass spectrometry, but the high nickel concentration produces a double ionized nickel spectral interference. The described procedure is based upon the formation of molybdovanadophosphoric acid when a molybdate solution is added to an acidic solution containing orthophosphate and vanadate ions. The optimum acidity for forming the yellow colored product is 0.5 N hydrochloric acid. The working concentration range is from 0.1 to 1 ppM phosphorus using 100 mm cells and measuring the absorbance at 460 nm. The sample preparation procedure employs aqua regia to dissolve the alloy and oxidize the phosphorus to orthophosphate. Cation exchange chromatography is used to remove nickel ions and anion exchange chromatography to remove gold ions as the chloride complex. Excellent recoveries are obtained for standard phosphorus solutions run through the sample procedure. The procedure is applicable to a variety of gold or silver braze alloys requiring phosphorus analysis.
- Research Organization:
- General Electric Co., St. Petersburg, FL
- DOE Contract Number:
- AC04-76DP00656
- OSTI ID:
- 5764068
- Journal Information:
- Metall. Trans., A; (United States), Journal Name: Metall. Trans., A; (United States) Vol. 10A:11; ISSN MTTAB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360101* -- Metals & Alloys-- Preparation & Fabrication
ALLOYS
AMMONIUM COMPOUNDS
BRAZING ALLOYS
CHEMICAL REACTIONS
ELEMENTS
GOLD ALLOYS
ION EXCHANGE MATERIALS
MOLYBDATES
MOLYBDENUM COMPOUNDS
NICKEL ALLOYS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PHOSPHORUS
POLYMERS
REMOVAL
RESINS
SILVER ALLOYS
SPECTROPHOTOMETRY
TRANSITION ELEMENT COMPOUNDS
VANADATES
VANADIUM COMPOUNDS