Nonconventional synthesis of praseodymium-doped ceria by flux method

The synthesis of Ce1-xPrxO2 solid solutions by three different methods (flux method, coprecipitation, and solid-state reactivity) has been investigated to establish optimal preparation conditions. The system studied was chosen because of its thermal and chemical properties and because of its utility as red and orange ceramic pigments. The results obtained showed that the Ce1-xPrxO2 solid solution can be achieved using all three preparation techniques. The three synthesis methods-flux, coprecipitation, and solid-state reaction-vary with regard to both the time and temperature used in the heat treatments, and the characteristics of the powders obtained (purity, morphology, granularity). In the preparation of powders by the flux method, the use of molten salts ensures a notable acceleration of the reaction kinetics. We found that the eutectic NaOH-KOH is particularly effective. The samples obtained exhibited a clearly spherical shape together with a considerable fineness. This nonconventional technique thus enables the synthesis of extremely homogeneous compounds that are especially suitable in industrial application such as pigments used in decorative ceramic materials. The solid solutions obtained are, indeed, able to develop an intense red coloring, especially these with a Pr content of 5 mol %.