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 TiLα and NKα 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 NKα and TiLα 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.