Cold sintering of complex-shaped ceramic materials

The present work explores for the first time the production of ceramic bodies with complex shape through the cold sintering process. Inspired by previous works on spark plasma sintering, a spacer accessory was designed to act as a removable mold. This proof-of-concept was tested with four different ceramic systems: biogenic hydroxyapatite, zinc oxide, diatomaceous earth and construction/demolition waste materials. In all cases, the density is comparable to that obtained by cold sintering of simpler disks. Moreover, the microstructure of the complex-shaped materials is substantially homogeneous in the entire component. Some distortions can be detected when comparing the spacer and sample shape, their control and modeling being a key challenge for future works.