Influence of Alumina Grade on Sintering Properties and Possible Application in Binder Jetting Additive Technology.

Alumina is one of the most popular ceramic materials widely used in both tooling and construction applications due to its low production cost, and high properties. However, the final properties of the product depend not only on the purity of the powder, but also, e.g., on its particle size, specific surface area, and the production technology used. These parameters are particularly important in the case of choosing additive techniques for the production of details. Therefore, the article presents the results of comparing five grades of AlO ceramic powder. Their specific surface area (via Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods), particle size distribution, and phase composition by X-ray diffraction (XRD) were determined. Moreover, the surface morphology was characterized by the scanning electron microscopy (SEM) technique. The discrepancy between generally available data and the results obtained from measurements has been indicated. Moreover, the method of spark plasma sintering (SPS), equipped with the registration system of the position of the pressing punch during the process, was used to determine the sinterability curves of each of the tested grades of AlO powder. Based on the obtained results, a significant influence of the specific surface area, particle size, and the width of their distribution at the beginning of the AlO powder sintering process was confirmed. Furthermore, the possibility of using the analyzed variants of powders for binder jetting technology was assessed. The dependence of the particle size of the powder used on the quality of the printed parts was demonstrated. The procedure presented in this paper, which involves analyzing the properties of alumina varieties, was used to optimize the AlO powder material for binder jetting printing. The selection of the best powder in terms of technological properties and good sinterability makes it possible to reduce the number of 3D printing processes, which makes it more economical and less time-consuming.