engleski

Stable ZrO2 suspension for slip casting into 3D-Printed moulds

Because of its excellent thermal and chemical stability, toughness, strength and wear resistance, and the biocompatibility, zirconium oxide ceramics has proven to be an interesting material for various applications. In order to prepare complex porous shapes suitable for biological implants or as catalyst support, we are investigating the possibility of slip-casting ZrO2 into 3D-printed polymeric moulds. Degradation of the mould material was investigated by differential thermal analysis and thermogravimetric analysis in order to establish suitable firing conditions for controlled degradation of the mould without damaging the ceramic green body. To prepare a stable suspension, a commercial ZrO2 powder (ZrO2-3Y, 25 nm) and a commercial polyelectrolyte DOLAPIX CE64 as dispersant were used. Suspensions were homogenized in a planetary ball mill using fully stabilised zirconia jar and balls. The effect of the dispersant to powder ratio, as well as various powder and distilled water ratios, was investigated. Water-based suspensions containing 50 wt.%, 55 wt.% and 60 wt.% of ZrO2 with 0.25 %, 0.5 % or 1.0 % DOLAPIX CE64 were prepared. The rheological properties of the suspensions were determined using a rotational viscometer, and the influence of ultrasound treatment of the suspensions was studied. Rheological measurements showed thixotropic behaviour of observed ZrO2 suspensions. Stable suspensions were prepared and cast onto a plaster mould. Microstructure of green and sintered samples was analyzed by scanning electron microscopy. Finally, preliminary casting into plastic moulds was performed.

ZrO2 ; slip casting ; rheological measurements ; microstructure

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