Zirconium Nitride (ZrN) Hafnium Nitride (HfN)

Publisher Summary The transition-metal nitrides Zirconium Nitride (ZrN) Hafnium Nitride (HfN) belong to a larger group of compounds having NaCl or A15 structure with extreme stability in a generalized sense that includes: hardness, chemical inertness, high melting point, and Young's modulus. This stability is the basis for the widespread technical use of these nitrides mainly as hard materials on cutting tools, abrasive applications, and more. There are numerous possible stoichiometry variations, because many of these compounds can form stable solid solutions with each other over wide ranges of composition. The basic reason for the high stability of these nitrides is their bonding that is an intricate mixture, of covalent bonds and ionic contributions. A characteristic and unusual result of this intricate bonding is that ZrN and HfN both are ceramic in terms of hardness, inertness, and directed bonds, but metallic with characteristically high electrical and thermal conductivity. The room temperature cubic unit-cell sizes of ZrN and HfN are 0.4577 and 0.4526 nm, respectively.