Densification of alumina coated with a Mg0-Al203-Si02 (MAS) glass was investigated from 1400 to 1600 deg C. spinel was observed to form at the liquid-alumina interface, whereas mullite crystallized uniformly in the liquid. Spinel and mullite crystallization kinetics were accelerated by smaller alumina particle size. Mullite and sminel crystallization retarded densification by forming a percolating network. Boron doping suppressed spinel formation, and thus alumina sintered to higher densities at low temperature. The concept of glass basicity is proposed as a usefulguide for selecting dopants for low-temperature sintering.
Origin
Pennsylvania State University, Usa
Journal Title
J Am Ceram Soc 81 5 1998 1163-1172
Sector
Special Glass
Class
S 1382