In this work the anisotropy of the creep behavior in hot pressed Si3N4 ceramics was evaluated. Four different Si3N4 ceramics were developed, using Al2O3-CRE2O3 or AlN e CRE2O3 as sintering aids. Specimens were hot pressed at 1750 °C - 20 MPa. The sintered specimens show different crystalline phases and microstructures, and were submitted to compressive creep tests at 1300 °C and stress of 300 MPa. Specimens in the parallel and perpendicular plane to the hot pressing axis were tested and the creep rates and strain were correlated as a function to the plane analyzed. The results show the influence of anisotropy on the creep behavior, related to the orientation of the grains, activating the rotation of the grains by viscous flow of the intergranular phase.
creep; hot-pressing; anisotropy
