3D printing of cordierite honeycomb structures and evaluation of compressive strength under quasi-static condition

Abstract

Ceramic honeycombs exhibit unique mechanical properties based on engineered formulations and geometry of cells. Extrusion of formable paste through a complex honeycomb die is the commonly practiced technique for the manufacturing of honeycombs globally. Extrusion die fabrication is a complex process which necessitates sophisticated infrastructure facilities that provide high geometrical accuracy and finish to produce defect free honeycombs. Furthermore, every configuration of honeycomb requires a specific tool. Additive manufacturing (AM)/ 3D printing is a rapid prototyping technique which offers flexibility in fabrication of honeycombs with desired geometries from a virtual model directly. Further, this does not require complicated dies. In this study, viscoplastic printable cordierite raw mix paste with a shear rate exponent of 0.87 was printed into honeycombs with hexagonal, square, and triangular cells using a ram type 3D printer. The printed honeycomb samples are found to possess good integrity and near net shape after drying. Sintered 3D-printed honeycomb samples of all configurations have exhibited cordierite as a major phase along with minor phases of magnesium aluminate (MgAl2O4) spinel, clinoenstatite (MgSiO3), and corundum (Al2O3) with sintered density of 2.41-2.48 g/cc. The samples are also subjected to compression testing under quasi-static condition. The study demonstrates 3D printing as a viable and flexible technique for rapid prototyping of honeycombs with desired configurations and engineered properties.