FUNDAMENTAL INVESTIGATIONS ON THE DECOMPOSITION BEHAVIOR OF SELECTED NITRIDES BY ON-MAT-8580

An assessment of the analytical quantifiability of nitrogen released b y thermal decomposition of nitrides was performed on the basis of the thermodynamic equilibria or the formation of nitride precipitates. Two reaction models are proposed; one including, the other excluding part icipation of carbon as a reactant. For the cases of selected nitride p hases (VN, BN, ZrN, Cr2N, Si3N4, NbN, AIN, TiN) it has been shown that thermal decomposition in a molten metal can be achieved in the presen ce of carbon. The experimental system employed the ON-mat 8500 instrum ent from Strohlein Laboratory, Measurement and Environmental Technolog y, Kaarst/Germany, which operates on a carrier gas/TCS principle. The empirically obtained degassing curves substantiate the proposed models . Nonetheless, a selective determination of nitrogen in a nitride phas e mixture proved impossible under the selected experimental conditions .