Synthesis of yttria stabilized ZrO₂–Al₂O₃ composite beads by wet titration technology

Abstract

In this work, based on the sol–gel and titration technology, an innovative method to prepare the yttria stabilized ZrO₂–Al₂O₃ composite beads which can greatly improve the bead properties is proposed. Using this method, the yttria stabilized ZrO₂–Al₂O₃ composite beads samples with different proportion of alumina component were prepared and tested. The density results show that the density of the ceramic beads is very close to the theoretical value, which implies that the new method can prepare the beads with high compactness and without containing pores. Vickers hardness results show that the hardness of the composite beads is higher than the zirconia beads without containing alumina. The SEM analyses show that the average grain size of the composite beads is about 180 nm, much smaller than that of the beads prepared by the conventional rolling process. X-ray diffraction results show that there is no monoclinic phase in the composite beads after sintering at 1250 °C. The EDS analyses show that the aluminum element exists in composite beads and the alumina grains are evenly distributed. Furthermore, the beads sintering temperature using this new process can achieve low-temperature which is about 1250 °C, much lower than that of the beads prepared by the conventional rolling process.