Microstructure control of continuously porous t-ZrO2 bodies fabricated by multi-pass extrusion process

Continuously porous t-ZrO2 bodies having different pore sizes were fabricated using the multi-pass extrusion process. The pore size depended on the number of extrusion passes, the extrusion ratio, and rod diameter and tube thickness. The pore size dramatically decreased as the number of extrusion passes and tube thickness increased. The pore sizes of the 2nd passed samples, which were made by a feed roll using different rod diameters and tube thickness, were about 260, 180, 150 and 90 μm in diameter while the 3rd passed samples which were made with different extrusion ratios (40:1 and 61:1) were about 80 and 35 μm in diameter, respectively. In the 2nd passed t-ZrO2 bodies sintered at 1550 °C, the relative density and bending strength decreased as the pore size increased. In the 3rd passed sample having a pore size of 35 μm, the bending strength increased as the sintering temperature increased up to 1550 °C. The maximum bending strength of the 3rd passed t-ZrO2 body was about 297 MPa.