Thermodynamic assessment of the Ca-Ca3N2 system

The Ca-Ca3N2 portion of the Ca-N binary system was investigated via thermodynamic modeling. All the experimental phase diagram information and thermodynamic data available from the literatures were critically reviewed and assessed by using thermodynamic models for the Gibbs energies of individual phases. A consistent thermodynamic data set for the Ca-Ca3N2 system was obtained by considering the present experimental results and reliable literature data. The calculated eutectic reaction occurred at 1.94 at.% N and 814 degrees C. Comparisons between the calculated and measured phase diagram and thermodynamic property showed that all of the accurate experimental information was satisfactorily accounted for by the thermodynamic description. The activity calculations implied that Ca has a strong tendency to fasten N in the melts, being a potential flux in growing GaN single crystals. (c) 2006 Elsevier B.V. All rights reserved.