It was recalled that previous nuclear magnetic resonance experiments and diffusion calculations had indicated that the distribution of N atoms in particles with a moderate N content was characterized by the existence of nitrided and non-nitrided regions. In order to detect this 2-region configuration directly, X-ray diffraction experiments were carried out on systematically ground nitrided samples. Nuclear magnetic resonance and X-ray diffraction investigations of vacuum-annealed samples showed that the 2-region configuration was stable, and that the N atoms did not diffuse further into the particle. Thermal conductivity detection methods indicated that only 5% of the inserted N atoms could be released by vacuum annealing at the nitridation temperature.

Y.D.Zhang, J.I.Budnick, W.A.Hines, D.P.Yang: Journal of Applied Physics, 1996, 79[8], 4596-8