High-precision and rapid layerless printing technology for high-solid and low-viscosity alumina slurry

Alumina ceramic samples with complex structures were prepared using a self-made down-mounted surface exposure forming system with a scraping mechanism and a ceramic slurry with an oxygen polymerization effect. A high-solid-phase, low-viscosity alumina slurry (1.55 Pa∙s viscosity at a 30 s−1 shear rate at 55 vol.%) was developed. The effects of exposure time and oxygen pressure on the curing thickness and contour accuracy before and after oxygen permeability were studied. Under the optimal oxygen pressure (0.4 kPa), oxygen generation could effectively reduce the error caused by the scattering of the ceramic powder, improve the contour accuracy of the inner hole, and reduce the size error of the inner hole by 7.2 % compared with the unoxygenated generation. According to the application requirements of aluminum-based ceramic parts, the corresponding degreasing and sintering curves were formulated, and the closed porosity of the ceramic (>40 μm) after sintering was 1.18 %, relative density was 69.3 %, apparent porosity was 29.3 %, and flexural strength was 41.53 MPa. This presents new potential technical avenues for the preparation of ceramic parts with complex structures.