Additive manufacturing of polymer-derived ceramics

Abstract

The extremely high melting point of many ceramics adds challenges to additive manufacturing as compared with metals and polymers. Because ceramics cannot be cast or machined easily, three-dimensional (3D) printing enables a big leap in geometrical flexibility. We report preceramic monomers that are cured with ultraviolet light in a stereolithography 3D printer or through a patterned mask, forming 3D polymer structures that can have complex shape and cellular architecture. These polymer structures can be pyrolyzed to a ceramic with uniform shrinkage and virtually no porosity. Silicon oxycarbide microlattice and honeycomb cellular materials fabricated with this approach exhibit higher strength than ceramic foams of similar density. Additive manufacturing of such materials is of interest for propulsion components, thermal protection systems, porous burners, microelectromechanical systems, and electronic device packaging.

Optically Clear and Resilient Free-Form <em>&micro;</em>-Optics 3D-Printed via Ultrafast Laser Lithography

“…It was successfully demonstrated using stereolithography at a millimeter-scale [25,26] or at smaller scale using commercially available photoresists [27,28]. Here we show a similar result in the micro-and nano-scales for SZ2080.…”

Fast and easy preparation of few-layered-graphene/magnesia powders for strong, hard and electrically conducting composites

“…For example, GNS/MgO composites [24] were prepared by a mixing route involving sonication of a graphene slurry, milling of a MgO slurry using ZrO 2 balls, mixing the two slurries, another cycle of grinding, filtration, drying, sieving, and hot-pressing. As opposed to these routes, in situ methods have been proposed for the formation of graphene/ SiC composites, consisting either in the epitaxial graphene growth on SiC grains during the densification by spark plasma sintering (SPS) [42] or in the nucleation of a graphene network from a Sipreceramic polymer such as a polysilazane, polysiloxane or polycarbosilane during sintering at high temperatures [43,44]. Here, we report a fast and easy, one-step, route for the production of graphene/ceramic powders, which does not require pre-existing graphene or any mixing step and can be applied to many different ceramics or even metals.…”

Architected cellular ceramics with tailored stiffness via direct foam writing

“…Recently, multiscale metamaterials with properties heretofore unseen in engineered materials have been created by light-based 3D printing of photopolymerizable organic (16)(17)(18)(19)(20)(21) and preceramic resins (22). Specifically, microlattices, octet structures, and tetrakaidecahedra with struts composed of hollow shells (16)(17)(18)20), solid features (21,22), or even finer trusses (16,19) have been produced, which may exhibit bending, stretching, or mixed mode mechanical responses. However, these lattices are limited to open architectures constructed using photopolymerizable materials that must be subsequently transformed to ceramic or metal through some combination of coating and pyrolysis.…”