China's Refractories

Abstract: Ceramic slurry of 78 mass% solid loading was prepared using photosensitive acrylic resin and dispersant SP-710 as the liquid phase, Al₂O₃ powder (d₅₀=2.38 μm) and TiO₂ powder additive as the solid phase. Alumina ceramics were prepared by DLP, sintering for 4 h at 1 450, 1 500, 1 550 or 1 600 ℃, respectively. The effects of the TiO₂ addition (0, 1%, 2%, 3% and 5%, by mass) on the properties of the ceramics were studied. The results show that the addition of TiO₂ can improve the sintering of Al₂O₃ ceramics, significantly improve the densification, and reduce the sintering temperature. With the optimum TiO₂ addition of 3% and the optimum sintering temperature of 1 600 ℃, the obtained Al₂O₃ ceramics have shrinkage of 15.7%, 15.8% and 23.8% at the x axis, the y axis, and the z axis, respectively, the porosity of 2.4%, the bulk density of 3.74 g·cm^-3 and the three-point bending strength of 251.1 MPa. Compared with the undoped alumina ceramics, the doped alumina ceramic has increased bulk density by 0.56 g·cm^-3, decreased apparent porosity from 20.2% to 2.4%, and the three-point bending strength increases by 2.5 times. Therefore, the density and the strength of DLP prepared ceramics can be improved effectively by adding an appropriate amount of TiO₂, and the performance of the DLP prepared ceramics is close to that of the pressed samples. Thus, it is hopeful to apply DLP in refractories field.

Key words: digital light printing, alumina ceramics, strength, bulk density, sintering aid