The determination of nitrogen in refractory metals

Schmitt and Fusban (58) simultaneously determined nitrogen and oxygen in 

Low nitrogen concentrations (0.01 to 1 i g/g) were observed in zirconium, niobium, molybdenum and tungsten. The samples analyzed were taken from monocrystals or batches subjected to special purification treatments. In the case of tungsten, an industrial product was used. 

The chemical separation of N by oxidizing fusion (chapter II, section 3.8.2) was used to determine nitrogen in titanium. However, to prevent excessively violent initiation of the oxidation reaction, it is important for the sample to be placed in the crucible beneath the flux. 

After activation, the samples were etched three times at 20°C in a bath containing 4 volumes hydrofluoric and 1 volume nitric acid. The concentration observed in an industrial titanium was (128 + 11) Mg/g (n = 13). 

The separation of N by reducing fusion in a graphite crucible in the presence of platinum (weight ratio Pt/Zr = 20) proved reliable. 

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