The Thermodynamic Characteristics of Nitrogen in Liquid Vanadium

摘要

In the authors' own experimental tests carried out under the conditions of thermodynamic equilibrium, nitrogen concentrations in liquid vanadium at a given temperature were determined for a preset nitrogen partial pressure. The experiments were carried out based on the levitation metal melting technique. The levitation melting of metals allows the ceramic crucible to be eliminated, whereby the reaction system is a liquid metal-gas two-phase system. The testing stand was equipped with an apparatus enabling the monitoring of the surface of the metal drop as it was saturated with nitrogen. Argon-nitrogen gas mixtures with a nitrogen faction of, respectively, 0.1, 0.2, 0.3, 2, 5 and 6 vol% were used in the tests. The lowest nitrogen partial pressure, at which experiments were conducted, was 304 Pa(0. 003 atm). In the testing conditions (temperatures of 2173, 2273 and 2373 K), a homogeneous solution of nitrogen in liquid vanadium was obtained. On the basis of experimental data, the value of the heat of nitrogen solution in liquid vanadium has been determined, and temperature relationships between the value of the equilibrium constant, lgK_(N(V)), and the free energy, ΔG~0, have been derived.