Abstract Scope |
In direct ink writing (DIW) of silicon carbide (SiC) ceramics, achieving precise viscosity control is critical for optimizing printability and structural integrity of printed components. Conventionally, organic binders have been employed to modify slurry viscosity; however, these additives necessitate subsequent removal, and complicating post-processing that potentially impacts final material properties. This study explores an alternative approach by systematically manipulating slurry pH and dispersant concentration to achieve desired viscosity levels without the use of additional binders. By deliberately inducing controlled under- or over-dispersion states within SiC slurries, viscosity and yield stress can be finely tuned to optimal DIW processing parameters. Rheological measurements combined with zeta potential analysis clarify the relationship between slurry stability, particle interactions, and resultant flow behavior. Adjusting the slurry pH into the acidic range protonates polyethyleneimine (PEI), initially enhancing dispersant absorption; however, further acidification leads to absorption loss. Conversely, when the solution becomes more basic, slurry stability begins to decrease. This binder-free approach not only simplifies the processing sequence but also preserves the purity and mechanical properties of the final ceramic components, representing a significant advancement in additive manufacturing of SiC-based materials. |