Precise determination of hydrogen in metals (with particular reference to zirconium) by the isotopic equilibration-mass spectrometry procedure

Abstract

A simple apparatus connected directly to a mass spectrometer enables the fairly rapid determination of hydrogen in metals to be carried out by isotopic equilibration with deuterium. Equilibrium conditions have been established from kinetic studies of the exchange process as a function of heating time. Results for titanium metal standards are in excellent agreement with the certified values, relative standard deviations (1σ) ranging from 3.3 per cent at 300 p.p.m. hydrogen to 0.8 per cent at 200 p.p.m. No standards are available for hydrogen in zirconium, Zircaloy, niobium, vanadium and hafnium. For these metals the equipment has been used to prepare samples with known hydrogen content. Analysis has verified the reliability of the technique. The sample size requirements are 0.1 to 0.5 g (usually 0.25 g) for the range 1000 to 10 p.p.m. hydrogen.