SYNTHESIS OF LOW-AGGLOMERATED YAG:Yb NANOPOWDERS FOR TRANSPARENT CERAMICS BY METHOD OF REVERSE CO-PRECIPITATION FROM CHLORIDE SALTS

Abstract

Subject of Research. The paper considers effect of ammonium sulfate, introduced at various stages of ceramic powders production, on the impurity content, morphology and degree of agglomeration of oxyhydrate powders and ceramic powders. Method. Synthesis of precursor powders was carried out by the method of reverse heterophase precipitation from chloride salts by spraying. Synchronous thermal analysis of oxyhydrate powders was carried out using differential scanning calorimetry and thermogravimetry. The content of chlorine and sulfur impurities in oxyhydrate and ceramic powders was determined by the method of energy dispersive analysis of the elemental composition. Morphology of the experimental samples was evaluated by scanning electron microscopy. Determination of the agglomeration degree for ceramic powders was carried out by the methods of X-ray phase analysis and gas adsorption of Brunauer, Emmett and Teller. Main Results. The research has shown positive effect of the ammonium sulfate usage at several stages of the ceramic powder production at once (chemical co-precipitation, washing, disaggregation). By applying an improved synthesis method, low-agglomerated (degree of agglomeration is less than 10) nanopowders with a specific surface area of 12.4 m2/g were obtained. Practical Relevance. Optical ceramics samples with the light transmission in the visible and near-IR range of more than 80% without taking into account the absorption bands of ytterbium were obtained.