CAREER: Novel Powder-Bed Ceramic Additive Manufacturing Assisted with Water-Based Inks, Layerwise Uniaxial Compression and Temperate Heating for Selective Particle Fusion

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Structural ceramics are strategically important in many specialty applications, including thermal insulators, armors, implants and sensors. Manufacturing of complex ceramic components, however, has always been problematic and can be costly and laborious due largely to their unique properties, e.g., high melting points and excessive hardness. Additive manufacturing (AM) offers an alternative to produce parts with complex geometries that are challenging to make using traditional manufacturing processes. While of a great potential, current ceramic AM technologies still have limitations in making complex structures with thick walls (e.g., thicker than 10 mm), because of the use of an organic binder and the difficulty in its complete removal during de-binding. This Faculty Early Career Development (CAREER) award supports fundamental research to investigate and mature a new ceramic powder-bed AM process that is assisted with water-based inks, so to eliminate the need of binder removing, followed by compression and mild heating to achieve particle fusion. If successful, this process will enable complex thick-walled ceramic component manufacture in a commercial scale and help accelerate wider adoption of ceramic AM in many industries, including healthcare, energy and defense. This project will also pique the interest of students at different grades in ceramic AM through ceramic-printing programs, including “Print-in-the-Dark-Side” for students with vision impairment, “Ceramic Art 3D Printing” for K-12 students, and cross-discipline ceramic printing initiatives for undergraduate students.This CAREER research aims to understand the processing mechanism of a new ceramic AM in making complex thick-walled ceramic parts through employing a selectively deposited water-based ink, followed by uniaxial compression layer by layer. Once the print is completed, mild heating is applied (50 to 200 Celsius) to the built powder bed, in which upon evaporation of the ink due to heating, particles in the ink-wetted region will be fused together. The project will study ceramic particles made of lithium molybdate, calcium phosphate and barium titanate, and employ instrumented compression tests (up to 100 megapascals), multi-scale experimental characterizations, and pore-scale numerical simulations to elucidate the effects of different processing conditions and material properties on the fusion mechanism and degree of ceramic particles, including the ink chemistry and saturation level, the compression magnitude, duration and cycles, as well as the heating temperature and time. The research findings are expected to uncover the mechanism that governs the neck formation and growth between ceramic particles in the studied ceramic AM process, identify the key factors that determine the particle fusion density and strength, and ultimately, enable making complex thick-walled ceramic components with minimum defects, full density and enhanced properties.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.