Thermodynamic and transport properties of an aluminum-nitrogen plasma mixture

Abstract

Thermodynamic and transport properties of an aluminum-nitrogen plasma mixture have been computed as a function of temperature for different percentages of the aluminum species. The calculations were made for an atmospheric pressure plasma having temperatures between 3000 and 25 000 K under the assumption of local thermodynamic equilibrium. Transport properties were calculated using a method derived from the Chapman–Enskog theory. The plasma mixture consists of Al, Al+, Al2+, Al3+, N2, N+2, N, N+, N2+, AlN, and electrons. Results show that the maximum number density of AlN is obtained at 67% of the aluminum species at temperatures close to 5000 K. The total enthalpy, viscosity, and total thermal conductivity of the plasma decrease at temperatures above 6000 K as the percentage increases. At temperatures below 17 000 K, the electrical conductivity, and the electron thermal conductivity increase with increasing aluminum percentage. The effective binary diffusivity of AlN as a function of temperature has a very strong dependence on the percentage of aluminum in the plasma.