Reaction of graphite and pyrographite with titanium and zirconium nitrides

Abstract

1. A study was made of the reaction of titanium and zirconium nitrides with graphite and pyrographite in a vacuum (0.1 N/m2) over the temperature range 1673–2473°K at contact periods from 1 to 5 h. 2. It was established that the reaction yields carbide phases which change to a MeC-MeN solid solution in an intermediate zone at the nitride interface. 3. It is shown that the growth of the carbide phases at constant temperature as a function of time obeys a parabolic law. 4. The intensity of reaction of each pair of materials at constant temperature depends on their physical state (bulk material, powder, or a combination of the two). 5. Pyrographite has been found to exhibit reaction anisotropy. Thus, in a direction parallel to the deposition plane, the intensity of reaction is 1.3 times the intensity of reaction in the direction perpendicular to this plane. 6. The possibility of reaction between graphite and titanium and zirconium nitrides was evaluated by thermodynamic calculation, which gave satisfactory agreement with experimental results.