A recent study has introduced a groundbreaking technique that addresses the shortcomings of traditional 3D printing methods, making it easier and quicker to create complex cellular ceramics. This new approach could transform how various ceramic materials are designed and processed, paving the way for exciting applications in fields like energy, electronics, and biomedicine, including uses in robotics, solar technology, sensors, battery components, and antimicrobial devices.
A recent study conducted by the School of Engineering at the Hong Kong University of Science and Technology (HKUST) has unveiled a groundbreaking technique that tackles the limitations of traditional additive manufacturing (3D printing). This method significantly streamlines and speeds up the creation of intricate cellular ceramics, potentially reshaping the design and processing of different ceramic materials and opening avenues for new applications in energy, electronics, and biomedicine, including robotics, solar technologies, sensors, battery components, and antibacterial devices.
Cellular ceramics are popular materials recognized for their consistent performance, resistance to wear, and durability. A research team led by Associate Professor YANG Zhengbao from HKUST’s Department of Mechanical and Aerospace Engineering has devised a new processing technique called surface-tension-assisted two-step (STATS) for creating cellular ceramics with specifically designed 3D cell configurations. This technique involves two main steps: (1) crafting organic lattice structures using additive manufacturing to form the foundational designs, and (2) infusing the lattice with a precursor solution containing the necessary materials.
One of the main challenges was managing the shape of the liquid involved. To overcome this issue, the team took advantage of surface tension—a natural force—to contain the precursor solution within the specially designed cellular lattices. By effectively utilizing the properties of surface tension to secure and hold fluids inside the constructed lattices, they achieved precise control over the liquid shapes and successfully produced highly accurate cellular ceramics.
The researchers also examined the geometric factors impacting the assembled lattices on both theoretical and experimental fronts, which helped in establishing the 3D fluid interface in organized configurations. After undergoing a drying process and high-heat sintering, the architected cellular ceramics were produced. The new STATS technique separates the material synthesis from the architectural construction, allowing for customizable manufacturing of cellular ceramics featuring a variety of cell sizes, shapes, densities, meta-structures, and material compositions. This method is highly programmable, making it suitable for both structural ceramics (like Al2O3) and functional ceramics (such as TiO2, BiFeO3, and BaTiO3).
To evaluate the effectiveness of this technique, the researchers investigated the piezoelectric properties of the cellular piezoceramics generated. They discovered that the method reduced microporosity while enhancing local density in the sintered cellular ceramics, mainly due to a significantly lower organic content in the raw material mixture. This advancement supports the production of cellular piezoceramics that are globally porous yet locally dense, achieving a considerable piezoelectric constant d33 (~ 200 pC N-1) even with an overall porosity exceeding 90%.
Prof. Yang shared that the inspiration for this method came from diatoms—single-celled algae that primarily inhabit sediment or cling to solid surfaces in water, serving as a direct and indirect food source for various animals. Diatoms are particularly known for their silica frustule, or outer cell wall, which is formed through a genetically programmed biomineralization process that results in precise structures with varying shapes, geometries, pore arrangements, and assemblies.
“Our approach addresses the constraints of traditional manufacturing techniques, allowing for the creation of intricate and programmable ceramic structures. This innovative method facilitates the processing of a diverse range of structural and functional cellular ceramics, aiding in applications such as filtration, sensing, actuation, robotics, battery electrodes, solar technologies, and antimicrobial devices. Additionally, our emphasis on interfacing fluids for solid fabrication opens a path for integrating interfacial processing with cutting-edge manufacturing, promoting the joint advancement of innovative designs and smart materials,” Prof. Yang elaborated.
