Fabrication of HAp-Coated Micro-Channelled t-ZrO2 Bodies by the Multi-Pass Extrusion Process

HAp-coated micro-channelled t -ZrO₂ bodies were fabricated using a multi-pass extrusion process in which carbon powders were used to facilitate the formation of pores and ethylene vinyl acetate was used as a binder. The unidirectional pores and HAp coating layers can be obtained easily, using the extrusion process. The micro-channelled bodies were 180 μm in diameter, and the HAp layer was uniformly coated on the pore walls. However, after being sintered above 1200°C, the HAp decomposed and was transformed into β-TCP, in which a large number of pores were observed. The maximum values of bending strength of HAp-coated and uncoated porous t -ZrO₂ bodies sintered at 1500°C were about 116 and 173 MPa, respectively, and their relative densities were about 57% and 63%, respectively.