Phosphorus content can be determined in the range of 0,001 % (m/m) to 0,025 % (m/m). Cr(III) and silica cause interference which is eliminated. The principle is dissolution of a test portion in a mixture of nitric and hydrochloric acids, fuming with sulfuric acid, oxidation of Cr(III) to Cr(VI), precipitation of Fe(III) phosphate and redissolution of the precipitate, addition of boric, tartaric and sulfamic acids, formation and extraction of molybdophosphoric acid, reduction of the heteropoly acid to molybdenum blue and back-extraction into an aqueous phase, measurement of the absorbance of the aqueous solution at 700 nm.
Document identifier
ISO 9388:1992
Title
Nickel alloys - Determination of phosphorus content - Molybdenum blue molecular absorption spectrometric method
ISO Category
TC 155/SC 3: Analysis of nickel, ferronickel and nickel alloys
Publication date
1992-08-01
International Relationship
BS 6783-12:1992
Price |
45 vnd |