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Strontium aluminates can be used as refractory construction materials at temperatures up to 2000 С or as the materials for immobilization of long-lived radioactive waste. The SrО-Al 2 O 3 system is one of the more complicated oxide systems used for the creation of new radio-transparent materials. The exploitation of such materials at high temperatures demands the knowledge of the thermal stability of the compounds and solid solutions formed in the SrО-Al 2 O 3 system. Methods: The synthesis of the samples in the SrO-Al 2 O 3 system was carried out by a ceramic method at 1250 C. The characterization of the samples was accomplished with the use of X-ray diffraction (XRD). The vaporization of the samples under study was performed from a twin tungsten effusion cell using the Knudsen effusion mass spectrometry method. Results: The temperature dependences of partial pressures of vapor species over 4SrOÁAl 2 O 3 , 3SrOÁAl 2 O 3 , SrOÁAl 2 O 3 , SrOÁ2Al 2 O 3 and SrOÁ6Al 2 O 3 in a wide range of temperatures were determined. The component activities, the Gibbs energies of mixing and the standard enthalpies of individual strontium aluminates were obtained. Conclusions:The thermodynamic properties of the SrO-Al 2 O 3 system at high temperatures are characterized by negative deviation from ideality. The vaporization processes and thermodynamic properties of the SrO-Al 2 O 3 system were obtained for the first time.

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