Rapid fabrication of Si3N4 ceramics with gradient appearance and microstructure.

Si3N4 ceramics with tailored gradient in color and microstructure were prepared by a rapid cost‐effective one‐step approach. The gradient microstructure was obtained by the manipulation of the dissolution‐reprecipitation process, by controlling the sintering temperature and sintering additive content. In the Si3N4 ceramics, the β‐phase content gradually changed from 84% to 11%. The Si3N4 ceramics exhibited white color on one side and showed a hardness of 19 GPa and fracture toughness of 7 MPa·m1/2 and may be suitable for bio‐implantation applications. [ABSTRACT FROM AUTHOR]