Bubble Alumina is produced by fusing special high purity alumina. The melt is automized with compressed air which leads to the hollow spheres.
Bubble Alumina is hard but extremely firable with respect to its pressure strength.
The melting point is approximately 21OOQC. Due to its hollow spheres it has a low bulk density and extremely low thermal conductivity. Bubble Alumina is chemically inert.
Due to the above noted properties bubble Alumina is used to form pores in high porosity abrasives and as a media to filtrate aggressive liquids or melts. It can also be used as a bed in the firing process of vitrified grinding wheels.