THERMODYNAMIC SIMULATIONS OF THERMOCHEMICAL PROCESSES IN AN ARC-DISCHARGE WITH VAPORIZATION OF A SAMPLE MATERIAL FROM THE ELECTRODE

A generalized thermodynamic model for thermochemical processes in a di rect-current are discharge with vaporization of a sample from both the surface and the crater of the electrode is developed. This model is b ased on partitioning a nonsteady nonequilibrium thermodynamic are-disc harge system into consecutive, locally quasi-equilibrium subsystems co rresponding to the stages of vaporization and thermochemical transform ation of a sample in a discharge plasma. The model involves thermodyna mic simulation of the gasphase composition over the surface of the vap orized sample at the effective electrode temperature, passage to the i nitial composition of the are-discharge plasma using the relationships obtained in this work, thermodynamic simulation of the composition of the are-discharge plasma with regard to ionization processes, and cal culation of the intensities of particular lines of atoms and ions. The validity of the generalized model was confirmed by comparison with ex perimental data.