Using agglomerate-free nanopowder as sliding friction reducer between alumina platelets in an ultraviolet-curable slurry for vat polymerization additive manufacturing

Nature’s ability to adapt and survive the harshest environment offers humankind an important source of muses in the efforts to create and improve existing materials. In this study, we demonstrated a concept of using agglomerate-free nanopowder as a sliding friction reducer between alumina platelets in a slurry. An ultraviolet-curable slurry containing predominantly alumina platelets exhibited favorable rheological characteristics to align the platelets with a coating blade in a vat polymerization printer. Consequently, a ceramic part with nacre-like structure could be printed and infiltrated with a secondary phase. Microscopy study on the fracture surfaces revealed various toughening mechanisms such as severing of the bridges between platelets and crack deflection by the platelets. Fracture of a three-point bent part mainly occurred due to the pull-out of platelets and failure of the polymer phase. The findings of this study suggest promising avenues for future research, including the additive manufacturing of larger objects consisting of nacre-like microstructures.