The present paper will demonstrate an innovative sustainable ceramic processing alternative that includes natural cellulose nanofibers (CNF). The use of CNF-based hydrogels can render highly homogeneous aqueous ceramic suspensions due to the increased hydrophilicity character. CNF can trigger weak interparticle association in these suspensions preventing sedimentation and segregation, thus allowing for the superior tailoring of the suspension constituents. When freeze-casting is employed, a powerful consolidation technique, it is possible to process various lightweight, mechanically rigid, thermally insulating anisotropic (ceramic) foams of high macro-meso porosity and surface area not requiring post-annealing or sintering steps.
 
In another example, CNF can be used for the fabrication of highly homogeneous ceramic matrix composites (CMC) as an alternative to carbon nanofillers. Establishing a 3D electrically percolating network in an insulating ceramic matrix is key to numerous engineering and functional applications. Using hydrophobic carbon nanofillers like graphene or carbon nanotubes is tempting, but still results in suboptimal performance due to processing challenges including colloidal instabilities in aqueous media. CNF can be in situ transformed during spark plasma sintering (SPS) into graphene-like networks when embedded in oxide ceramic matrices not prone to anisotropic alignment, enhancing both the transport and the mechanical properties of the obtained, highly refined ceramic microstructures.
 
Our present research focus aims at translating such in situ ceramic matrix functionalization to the field of additive manufacturing, where the challenge is in feedstock modification and to establish a rapid sintering protocol not using the mechanical pressure nor the electric current/field (operating in SPS) to allow sintering of complex-shaped, multimaterial ceramic (micro)structures.