Mechanochemical nitridation by ball milling iron with pyrazole: a structural investigation

Nitrides of iron have been obtained by mechanochemical treatment of Fe powder with the amine compound, pyrazole (C3H4N2). The structural developments which occur during the milling of the Fe and pyrazole powder mixture have been monitored by x-ray diffraction. The hexagonal ɛ-Fe3Nx phase with x ~ 1.1–1.2 was found to be the main milling product. The decomposition of the nitride and the formation of iron carbide Fe3C have been observed after transient heating at 550 °C. Analysis of x-ray diffraction data for the as-milled and thermally treated powders has led to information on the locations of the carbon and the hydrogen stemming from the pyrazole compound.