Ultrafast high temperature sintering and bioinspired microstructures as a more sustainable route to strong and tough alumina ceramics: A comparison with conventional sintering and challenges for high-performance

The annual increase in global CO 2 emissions from consumer goods consumption has created an urgent need to find alternative, sustainable routes for processing materials without compromising performance. Among consumer goods in ceramics, structural ceramics account for a major share, necessitating the development of more sustainable fabrication techniques. Moreover, bioinspired microstructured ceramics are uniquely strong and tough, and are therefore promising for future ceramic development. In this work, we compare ultrafast high-temperature sintering (UHS) and conventional pressureless furnace sintering in an electrically heated box furnace (CS) for the sustainable fabrication of bioinspired alumina ceramics starting from the same green body. Two bioinspired microstructured alumina ceramics, nacre-inspired and Bouligand-inspired, were fabricated using both sintering methods. The mechanical properties obtained after optimizing the sintering processes are compared, and the best material is identified. Our analysis shows that UHS provides slightly higher mechanical properties while achieving minimum CO 2 emissions and a reduced overall ecological footprint by approximately 98.5% and 55%, respectively, compared to CS. Moreover, under ideal conditions, UHS has a 23% lower ecological footprint than commercial large-scale processing used for alumina production. Despite the sustainability benefits, significant challenges remain for the large-scale production of such bioinspired ceramics using UHS. Nevertheless, the UHS process could open a new pathway to the production of high-performance structural ceramics while reducing adverse environmental impacts.