Effect of ball-milling time on the properties of AlN ceramics fabricated via digital light processing

Aluminum nitride (AlN) ceramics are widely utilized in various applications due to their exceptional properties. However, fabricating complex AlN components using conventional machining techniques remains challenging. To address this issue, Digital Light Processing (DLP) is proposed as a viable technique for manufacturing intricate AlN ceramics. A key challenge in this process is the moisture absorption and hydrolysis of AlN powders, which significantly increase slurry viscosity and affect the layer-by-layer accumulation of AlN slurry. This study systematically investigated the particle size distribution, rheological behavior, and curing kinetics of AlN slurry processed with different ball-milling times. At a ball-milling time of 8 h, the slurry with a 54 vol% solid loading exhibited a viscosity of 21.1 Pa.s at a shear rate of 27 s −1 and a curing depth of 83 μm at an energy dose of 74.4 mJ/cm². Following debinding and sintering, the sintered AlN ceramics achieved a flexural strength of 98.7 MPa, a bulk density of 2.74 g/cm³ , and an open porosity of 12.82 %. These findings provide critical insights into optimizing slurry preparation and processing parameters for the DLP-based fabrication of AlN ceramics.