Improved performance of 3D printed alumina ceramics by adding polystyrene microspheres

For ceramic cores, how to balance porosity and mechanical properties is one of the hot research topics. By adjusting the type and content of the pore-forming agent, the pore distribution and shape of the ceramic can be affected, thus changing the performance of the samples. Therefore, it is important to investigate in detail the processing technology of ceramic cores. Alumina ceramics were prepared by using alumina as raw material and crosslinked polystyrene spheres (20 μm) as a pore-forming agent. The effects of polystyrene content, sintering temperature, and printing method on the properties of the samples were investigated. Alumina ceramics with different polystyrene content were printed in vertical and horizontal printing modes, and then the printed samples were sintered at different sintering temperatures. The properties of the samples were measured by measuring the flexural strength and observing the surface morphology and surface roughness. It was found that in horizontal mode printing, samples with smaller surface roughness and higher flexural strength were be obtained. When the content of polystyrene microspheres was 9 %, the overall properties of samples sintered at 1500 °C were the best. In these conditions, the flexural strength was 16.67 ± 0.94 MPa, the shrinkage rate 2.25 ± 0.09 %, the bulk density 1.87 ± 0.05 g/cm3, the open porosity 26.61 ± 0.38 %, and the mean roughness 5.70 ± 0.73 μm.