Hybrid microwave sintering of Zirconia Toughened Alumina in a multimode cavity – Influence of the content of 3 mol% yttria stabilized zirconia and sintering configurations

MW sintering is a sintering process in which samples directly heat by absorption of the electromagnetic field, leading to a fast volume heating. Thus, the materials are heated due to their own dielectric properties. Zirconia Toughened Alumina (ZTA) is of particular interest for MW sintering because of the difference of dielectric properties between alumina and zirconia. In this study, ZTA pellets with different volume fractions of zirconia were sintered in a MW multimode cavity with different sintering cells, i.e., with or without susceptor. These experiments show that all the samples were densified whatever the configuration. But the evolution of power and temperature vs time during the sintering cycle shows a better heating capability when the volume fraction of zirconia increases. The influence of the material to heat is more visible when sintering without susceptor. This was confirmed by other experiments, where the samples were heated by a constant incident power in a single-mode cavity.