Determination of nitrogen in titanium, aluminum, silicon, hafnium nitrides and compositions on their base using a Metavak-AK analyzer

Methods for determining nitrogen in the products of self-propagating high-temperature synthesis (SHS), i.e., titanium, aluminum, silicon, and hafnium nitrides using a Metavak-AK gas analyzer have been developed. The optimal modes of analysis have been selected: the time and temperature of degassing of the crucible with flux in the furnace, the time and temperature of purging the extraction chamber with the sample, the time of automatic dumping of the sample from the loading chamber into the crucible, the time and temperature of purging the chamber after loading, the time of removal of gaseous products of reduction melting and registration of nitrogen signals. Furnace operating programs were compiled to determine the nitrogen content in TiN, AlN, Si3N4, HfN. Reduction melting of the samples took place in a helium flow at a furnace temperature of 2700°C for TiN, AlN, HfN, and 2500°C for Si3N4. To speed up the process and complete nitrogen extraction, a metal bath was used: nickel grit in the case of titanium and hafnium nitrides, and combined Sn/Ni flux for aluminum and silicon nitrides. The nitrogen content in the studied samples was determined in the range from 0.12 up to 39.3 %wt., the relative standard deviation was 0.6 – 3.6%. The accuracy of the results obtained on a Metavak-AK gas analyzer is confirmed by the Kjeldahl and Dumas reference methods.