Synthesis of submicron, nanostructured spherical powders of Y3Al5O12-phases by the method by ultrasonic spray pyrolysis and investigation of their structure and properties

Abstract

The results of laboratory studies of the submicron Y3Al5O12 (YAG) phase powders synthesized by ultrasonic spray pyrolysis are presented. A structural-phase analysis of aerosol powders was carried out and an assessment of the tendency of the synthesized powders to sintering was made. The working solution for the aerosol was prepared on the basis of distilled water with aluminum nitrate hexahydrate Al(NO3)3 x 6H2O and yttrium nitrate hexahydrate Y(NO3)3 x 6H2O dissolved in specified proportions. Spherical submicron nonagglomerated powders of Y3Al5O12–phase with a small YAlO3-phase content were synthesized by this method. Powder granules with a diameter of 0.75 microns had a nano-fragmentary polycrystalline structure with an average crystal size of 16 nm. During the sintering of powders with such a unique structure, diffusion mass transfer processes are activated, which contributes to a more efficient compaction of the material. Aerosol powder sintering experiments have shown that the best results are achieved when the process is carried out at 1700 °C for 6 h. As a result, a dense YAG-ceramic material was obtained, the structure of which does not contain residual pores and is characterized by a uniform distribution of equiaxed grains.