Nitrogen Partial Pressure of Stoichiometric and Nonstoichiometric Titanium, Vanadium and Niobium Nitrides and Carbonitrides

A method is proposed for calculating the nitrogen equilibrium partial pressure pN2 of stoichiometric and nonstoichiometric nitrides MNy and carbonitrides MCyN1ÿy (M ˆ Ti, Zr, Hf, V, Nb, Ta) with B1(NaCl)-type structure. Analytic forms are derived for the composition, nonstoichiometry, and temperature dependences of the nitrogen partial pressure of the afore-mentioned compounds. The partial pressure of N2 for the MNy nitride or MCxNy carbonitrides at a given temperature T is found to be proportional to the pressure of nitrogen for MNyc nitride evaporating congruently at that temperature T. The nitrogen partial pressure pN2 …y; T† of titanium nitrides TiNy …0:45 y 1:0† and carbonitrides TiCxNy …0:50 x‡ y 1:0; 0 y 1:0†, vanadium nitrides VNy …0:55 y 1:0† and carbonitrides VCxNy …0:60 x‡ y 1:0; 0 y 1:0†, niobium nitrides NbNy …0:70 y 1:0† and carbonitrides NbCxNy …0:70 x‡ y 1:0; 0 y 1:0† of various compositions at temperatures of 1000 to 2400 K are calculated. The calculation results are compared with the experimental data of literature.