3D Printable Ceramic Paste for Magnesium Rapid Prototyping

In this work, an extrudable ceramic paste is being developed, that in the sintered state can act as a non-reactive mold for producing magnesium castings. This paste would allow molds to be 3d printed from a computer aided drafting (CAD) file, which could then be used to create intricate cast magnesium shapes. Magnesium is notoriously difficult to cast, as it reacts with most refractory compounds that have been used in the 3d printing process. Despite this drawback, magnesium is an attractive material due to its lightweight, good mechanical and damping properties, as well as its biodegradability. If successful, this new technology would allow for the production of custom magnesium prototypes and components for the transportation, aerospace, and biotechnology sectors. CaCO3 is being studied as a starting material for producing molds for magnesium bone scaffolds. Pastes with varied binder and dispersant compositions were produced by acoustic mixing and then extruded into simple test coupons. The sintering behavior of the pastes were evaluated by thermo-gravitational analysis (TGA), systematic sintering heat treatments, and hardness measurements. Finally, the flexural properties of the sintered pastes were evaluated by 3 point bend tests. The initial results of this work have shown that the binder and dispersant system can be removed during the sintering process with very little ash content high CaCO3 volume percentages can be achieved in the green compact. It is expected that the sintered strength will be equivalent to that of an investment casting shell mold