Journal of the American Ceramic Society, Vol.93, No.9, 2617-2621, 2010
Hot Pressing of Spherical, Polycrystalline 3Y-TZP Particles
As an alternative route to hot-pressing fine powders for obtaining fine-grained microstructures, coarse spherical polycrystalline particles having a fine-grained microstructure were hot pressed. Three size fractions of particles, nominally 25, 45, and 75 mu m, were prepared by presintering Tosoh yttria-stabilized zirconia (Y-TZP) spray-dried granules. Samples were hot pressed at 1350 degrees C for 1 h using pressures of 6, 10, 20, and 40 MPa. It was found that dense (> 98%) 3Y-TZP monolith could be produced at 40 MPa, which retained the fine grain size (0.3 mu m) of the starting polycrystalline particles. The densification rate was particle size independent when the pressure was at least 10 MPa. It was determined that the densification rates agreed with Helle et al.'s predicted rates based on superplastic creep-controlled hot pressing.