Dielectric Properties of ZrC by Electron Energy Loss Spectroscopy

Abstract Zirconium carbide belongs to the group of refractory compounds having NaCl structure with high chemical inertness and melting point, characteristics that have made these materials to play a prominent role as hard coatings and these properties are closely related to their electronic structure. The electronic configuration of ZrC is: (Xe) 5d2 6s2, one s electron being able to be promoted to a d orbital forming four equivalent sd3 hybrid orbitals, favoring covalent bonds maintaining, however, a percentage in ionic character of about 30%. Some attention has been paid in the last two decades in studying the optical properties of transition metal carbides and nitrides by electron energy loss spectroscopy (EELS), being TiC and TiN the most extensively reported. In this work the optical constants of commercial powder ZrC were obtained using a Gatan Parallel Detection Electron spectrometer (model 766) attached to the CM-200 transmission electron microscope (TEM).