Preparation of spherical and dense Na2O–B2O3–SiO2 glass powders by ultrasonic spray pyrolysis technique

The preparation of spherical and dense glass powders was investigated by ultrasonic spray pyrolysis technique through different reactor temperatures (200–1200 °C) using the composition of 46.25 wt.% SiO2, 26.86 wt.% Na2O and 26.87 wt.% B2O3 and their phase evaluation, particle size and shapes, densities and specific surface areas were determined. The results were compared with glass powders obtained via classical melting technique for the same composition. The powders produced by ultrasonic spray pyrolysis technique at or above the reactor temperature of 700 °C have amorphous structure. Particles with spherical shape and smooth surfaces could be obtained at and above the temperature of 900 °C. The particles have the same densities with the particles obtained by melting technique. The spherical particles also have a narrow size distribution (700–2400 nm). Thus, they have a potential to be used in engineering applications such as thin film coating and especially capillary membrane filter production.