Spectrophotometric determination of yttrium in chromium and chromium-base alloys with arsenazo III

Abstract

A method has been developed for determining yttrium in the range 50 p.p.m. to about 4 per cent. in chromium and chromium-base alloys. The procedure involves the separation of yttrium from chromium(VI) by precipitation of yttrium hydroxide from an ammoniacal chloride solution; aluminium hydroxide is used as a “collector.” The mixed hydroxides are dissolved in dilute nitric acid, and yttrium is subsequently determined spectrophotometrically by a procedure based on the formation of a bluecoloured complex with arsenazo III. Absorbance of the complex is measured at a wavelength of 660 nm.

The effects of common alloying constituents and likely impurities have been investigated, and modifications to the method have been introduced to overcome interference by aluminium, iron, titanium, zirconium, hafnium, niobium and tantalum.