Investigating the effect of polymer additives on the rheology of SiC/clay paste for use in Direct Ink Writing method

In this study, we investigated the impact of polyethylene glycol, sodium carboxymethyl cellulose, and polyvinyl alcohol on the rheological behavior, printability, and mechanical/physical properties of 3D‐printed scaffolds for high‐temperature applications using SiC/clay ceramic paste. Employing the Direct Ink Writing method, varying concentrations of each polymer (PEG: 2.5%–10% weight, CMC: .6%–1.8% weight, PVA: .25%–1% weight) were incorporated into the composition. The resulting SiC/clay paste, with adjusted additive content, was used to 3D‐print scaffold structures through Direct Ink Writing. Sintering of clay‐bonded SiC samples were carried out at 1300°C for 1 h in an ambient atmosphere. The research revealed that altering the additive amounts significantly influenced the rheological behavior, mechanical properties, and physical characteristics of the printed specimens. Notably, the ideal properties with additive concentrations (10% wt PEG, 1% wt PVA, and .6% CMC) were identified, providing the best outcomes in terms of printability and firing results. High density samples with 2.09, 1.93, and 1.79 g/cm3, high compression strength of 20.82, 14.5 and 12.53 MPa with 32.26%, 42.5%, and 52.63% open porosity for samples containing PVA, CMC, and PEG modifiers were obtained, respectively. Additionally, the study led to the development of a high solid loading printable paste with an 80% weight.