Nitrogen determination in refractory metals. Its economic and technological importance

The properties of refractory metals (Nb, Ta, Mo, W, V, Ti, Zr and their alloys) are reviewed. The methods used for the determination of N in these metals are discussed and compared: classical methods such as chemical analysis methods, carrier gas fusion method, vacuum fusion method... and laboratory methods such as spectrometry, activation analysis followed by a chemical separation, direct nuclear reaction analysis. An attempt is made to define the technological importance and economic aspects of the determination of N in these metals