The determination of nitrogen in refractory metals by charged particle activation analysis

An instrumental determination of nitrogen in Ti, Nb and Ta, using the (p,n) reaction, is possible with a precision of 10% or less. The results obtained for Nb and Ta using the (p,n) reaction are confirmed by the results obtained using the (p,α) and the (d,n) reactions. The (d,n) reaction can be used for Mo and W, on the condition that the nitrogen content is above resp. 5.7 μg/g and 0.11 μg/g. Moreover deuteron activation allows a simultaneous determination of three elements in less than one hour. For Mo and W a destructive analysis was elaborated. The precision obtained in this sub μg/g concentration region is better than 10%. The sensitivity of the chemical methods is above this concentration level, so that only activation analytical methods can be used, when Mo and W have to be certified. For the destructive analysis, described for Zr, the reliable determination of the chemical yield is an important advantage. The method is however less sensitive than the other methods discussed. (orig.)