Abstract

Oversaturated oxynitride glasses as well as bulk ceramics were designed in order to investigate the impact of 6 different metallic elements that form Me3+ cations of varying radius on grain growth anisotropy and mechanical behavior of silicon nitride ceramics. We show that grain growth anisotropy and toughness increase with increasing cation size, which seems to be the result of a preferred segregation of large Me3+ cations on the prism planes of Si3N4 grains. Furthermore, the experiments reveal that the electronic configuration of the metallic element seems to have an impact on the behavior of the Me3+ in the intergranular film.