Synthesis, vaporization and thermodynamic properties of superfine yttrium aluminum garnet

The study of high temperature behavior of Y3Al5O12 is urgently required for development of high temperature materials of the new generation including ultra-high temperature ceramics. The superfine Y3Al5O12 powder was obtained by the glycol-citrate method; the aggregation process of the sample synthesized was investigated under calcination conditions at different temperatures. Using the Knudsen effusion mass spectrometric method vaporization processes and thermodynamic properties of Y3Al5O12 as well as of the melts in the Y2O3-Al2O3 system were studied at temperatures higher than 2270 K. The simultaneous transition to the gaseous phase of both Al2O3 and Y2O3 from the melt under study was observed during isothermal keeping of the Y3Al5O12 sample at the temperature 2675 K with the predominant alumina removal. Analysis of the values of the thermodynamic properties obtained in the Y2O3-Al2O3 system showed negative deviations from ideal behavior despite the possibility of existence of the miscibility gap at the temperature 2675 K. [Display omitted] •The superfine Y3Al5O12 powder was obtained by the glycol-citrate method.•The Y3Al5O12 vaporization was studied at the temperatures 2270–2675 K.•Partial pressures of vapor species over the Y2O3-Al2O3 system were found at 2675 K.•The thermodynamic properties of the Y2O3-Al2O3 melts were studied at 2675 К.