X-ray spectral investigation of the electronic structure and chemical bonding in ultradispersed powders and the fine-grained materials obtained from them. I. Titanium nitride

The dependence of the electron energy spectrum of ultradispersed TiN powders on particle size was studied by the method of ultrasoft x-ray spectroscopy. A relative narrowing of the x-ray TiL_α and NK_α emission bands (which reflect the energy distribution of valence Np- and Tid-states) depended on the specific surface area of the powders and charge states of the Ti and N atoms. It was shown that narrowing of these bands is due to localization of the Np- and Tid-orbitals of surface atoms as a result of breaking Ti−N bonds. Broadening of the NK_α and TiL_α bands in certain energy ranges was observed after compacting ultradispersed powders. This is a result of Tid and Np orbital splitting caused by the formation of Ti−N bonds between the surface atoms of neighboring particles brought into contact at high pressure and temperature. Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 7–8(408), pp. 75–85, July–August, 1999.