The precise determination of nitrogen in boron nitride

In order to further improve the high performance ceramic material BN it is necessary to advance its analytics. The quantitative determination of the nitrogen content as main component is compared by three methods: the carrier gas hot extraction, the LiOH fusion and the Kjeldahl method. Thereby specific methodical aspects are critically highlighted with respect to the trueness and precision of the nitrogen analysis. The “chemistry” plays a fundamental role in all methods. In the case of the instrumental analysis by CGHE important critical aspects are the calibration of CGHE measurements and the improvement of reproducibility which needs a much better understanding of the chemical reactions in the crucible. In case of the Kjeldahl method it is of decisive importance to apply an adequate high temperature of 260 °C for decomposition, whereas the melt-decomposition with LiOH is affected by melt additions.