Synthesis, vaporization and thermodynamics of ceramic powders based on the Y2O3–ZrO2–HfO2 system

Abstract

Nano-particles of refractory oxides based on the Y2O3–ZrO2–HfO2 system (cubic phase) were synthesized using the glycol-citrate method. The dependence of the morphology and fineness of the powder obtained on the heat treatment conditions was considered. Vaporization processes and thermodynamic properties of ceramic powder in the Y2O3–ZrO2–HfO2 system were studied by the Knudsen effusion mass spectrometric method in the temperature range 2700–2925 K. It was found that at the temperature (2773 ± 40) K the ceramic powder containing Y2O3:ZrO2:HfO2 as 0.15:0.60:0.25 mol fractions underwent a congruent sublimation. The phenomenon observed was confirmed during ten hours vaporization under conditions intermediate to the equilibrium state and the evaporation from the exposed surface. This experimental observation may be successfully used for the development of advanced high temperature coatings based on the ceramics of the Y2O3–ZrO2–HfO2 system.