Direct microwave sintering of gamma-alumina powder: effect of alpha seeding and magnesia doping

摘要

Microwave sintering as a rapid processing technic has been extensively investigated in the past decades. During microwave heating, the material couples with the electric field, absorbs the electric energy in its bulk and transforms it into heat. The microwave coupling behaviour depends on the dielectric loss factor. In most of pure oxide ceramics such as alumina the loss factor is very low at room temperature and increases with increasing temperature. Routinely a high dielectric loss material is used as a susceptor for heating the green specimen up to a temperature at which it significantly couples with the microwaves ; this process is referred to as "hybrid microwave sintering".