Using an aerodynamic levitation furnace, a series of transparent (1-x)LaAlO3-Nb2O5 amorphous spheres (x: molar percent of Nb2O5) were successfully fabricated. The formation ranges of the amorphous spheres were 0 <= x <=, 0.2 and 0.6 <= x <= 0.7, and their diameters were about 2 similar to 4 mm. The glass transition temperature T-g and crystal onset temperature T-x decreased with increasing x. Delta T (Delta T = T-x - T-g) was an important parameter for measuring the glass-forming ability. With rising x, the critical cooling rate changed consistently with Delta T did, indicating that this rate was also effective for evaluating the glass-forming ability. The highest refractive index at 587.6 nm was 2.26 for x = 0.7. In the entire visible light region, the transmittance exceeded 70%. These amorphous materials are useful for developing optical devices in the visible band. With increasing x, the Vickers hardness rose firstly and then decreased, reaching maximum at about 8.3 GPa for x = 0.2.

aerodynamic levitation furnace; transparent; critical cooling rate; high refractive index; LaAlO3-Nb2O5 amorphous sphere

Inner Mongolia University of Science and Technology; Northeastern University