Determination of copper, nickel and iron in heavy alloy using atomic-absorption spectrophotometry

Abstract

A method is presented for the rapid and fairly accurate atomic-absorption spectrophotometric determination of the major alloying elements and a minor constituent element of the tungsten-based heavy alloy 90 tungsten 7.5 nickel-2.5 copper. The sample is dissolved in a mixture of hydrofluoric and nitric acids. Ammonium citrate is added to keep the tungsten in solution, which is later neutralised with ammonia and made up to a suitable volume. Flame absorbance measurements are made under specified instrumental conditions for the three elements. The effect of variation of tungsten concentration in the matrix and of the variation of the concentration of ammonium citrate, nitric acid and hydrofluoric acid on each of the mentioned constituents is evaluated.