  Ceramics are highly technical materials with properties of interest for
multiple industries. Precisely because of their high chemical, thermal, and
mechanical resistance, ceramics are difficult to mold into complex shapes. A
possibility to make convoluted ceramic parts is to use preceramic polymers
(PCP) in liquid form. The PCP resin is first solidified in a desired geometry
and then transformed into ceramic compounds through a pyrolysis step that
preserves the shape. Light-based additive manufacturing (AM) is a promising
route to achieve solidification of the PCP resin. Different approaches, such as
stereolithography, have already been proposed but they all rely on a
layer-by-layer printing process which sets limitations on the printing speed
and object geometry. Here, we report on the fabrication of complex 3D
centimeter-scale ceramic parts by using tomographic volumetric printing which
is fast, high resolution and offers a lot of freedom in terms of geometrical
design compared to state-of-the-art AM techniques. First, we formulated a
photosensitive preceramic resin that was solidified by projecting light
patterns from multiple angles. Then, the obtained 3D printed parts were
converted into ceramics by pyrolyzing them in a furnace. We demonstrate the
strength of this approach through the fabrication of dense microcomponents
exhibiting overhangs and hollow geometries without the need of supporting
structures, and characterize their resistance to high heat and harsh chemical
treatments.
