Optimization of 3D Printing Parameters for Alumina Ceramic Based on the Orthogonal Test

In this paper, an alumina ink with good rheological properties was successfully prepared using pseudoboehmite as the main component, nitric acid as the colloidal solvent, and sesbania powder as the lubricant. The impact of nine different ink formulations, namely, Ink1 to Ink9, on the printability and rheological features of the ink was investigated. Consequently, it was found that Ink3 with 5 wt % nitric acid and 5 wt % sesbania powder exhibited the most favorable formability. This ink was utilized to fabricate alumina samples with direct ink writing (DIW) three-dimensional (3D) printing technology. The printed alumina samples were characterized using an automatic Brunauer-Emmett-Teller, X-ray diffractometer, Fourier transform infrared spectroscopy, and scanning electron microscope. To obtain the optimal printing parameters, a three-factor and three-level orthogonal test was designed to research the influences of different 3D printing parameters (filling ratio, nozzle diameter, and layer thickness) on the specific surface area, pore characteristics (size and volume), and radial crushing strength of the alumina specimens. The primary and secondary orders of the effects on the radial crushing strength and pore structure were determined through analysis of the experimental data. The experimental results showed that the alumina sample with a filling ratio of 80%, nozzle diameter of 0.6 mm, and layer thickness of 0.3 mm was found to have better strength of 48.07 ± 9.53 N/mm and specific surface area of 185.7315 m²/g. This study provides a theoretical base for the preparation of alumina carriers by DIW 3D printing.