Thermodynamics of the Al–C–O Ternary System

The vaporization behavior of the system, either as mixed powders or as two bulk samples, was studied by high-temperature mass spectrometry with the multiple Knudsen cell method. Using different orifice sizes, the direct comparison of partial pressures shows that nonequilibrium vaporization occurs. With the multiple-cell method, the gross evaporation and condensation coefficients for the three species , , and at the alumina surface and at the graphite surface were determined. Results showed that condensation coefficients vary in the range, while evaporation coefficients remain very low, especially for bulk samples.