Chinese scientists develop 4D printed ceramics

Researchers have developed a technique for printing ceramics that can self-reshape.

At Springwise, we have covered several innovations in 3D printing. These have included printing personalised ballet shoes, skin grafts and bike tyres. Now, a research team at City University of Hong Kong have developed the world’s first 4D ceramics printer. Unlike 3D printing, where printed objects cannot change shape, 4D printing involves objects that can re-shape or self-assemble themselves over time when implementing external forces, such as pressure, temperature or a magnetic field.

The CityU team developed a ‘ceramic ink’. This ink is a mixture of polymers and ceramic nanoparticles. Applying the ink to the 3D-print ceramic precursors which are flexible and stretchable enough allows the formation of complex shapes. The ceramic precursors also store elastic energy. When releasing the stretched ceramic precursors, they undergo self-reshaping. The precursors then become heat treated, which turns them into hard ceramics.

The finished ceramics are strong and have a high strength-to-density ratio. This means that they can be made in larger sizes than other printed ceramics without compromising strength. According to team leader Professor LU Jian, Vice-President (Research and Technology) and Chair Professor of Mechanical Engineering, “The whole process sounds simple, but it’s not … Like squeezing icing on a cake, there are a lot of factors that can affect the outcome, ranging from the type of cream and the size of the nozzle, to the speed and force of squeezing, and the temperature.”