Fig. 4From: Synthesis and Characterization of Nanoscale Tungsten Particles with Hollow Superstructure Using Spray Drying Combined with Calcination ProcessThe microstructure of spray-dried (NH4)6W7O24·6H2O particles in different high-pressure gas. a 150 L/min. b 200 L/min. c 250 L/min. d 300 L/min. e BET surface area. f Average particle sizeBack to article page