Tuning the Mechanical Properties of Gelcast Bodies During Drying Process via a Physically and Chemically Crosslinked Gel System

Gelcasting is a widely developed ceramic forming technique; however, a persistent challenge lies in the drying process, where cracking and deformation frequently occur, hindering the further development of gelcasting. In this study, a strategy was proposed to address warpage and cracking during drying through gel structure design, aimed at increasing the ultimate strain of the bodies. The stress–strain curves of the bodies were analyzed at the wet body, ethanol body, and dried body stages. The effects of different gels on the mechanical performance of the bodies and their roles in regulating drying stress were further examined. The incorporation of flexible polymer segments into the polyethylene glycol diglycidyl ether/polyethyleneimine (PEGDE/PEI) system enhanced the strain capacity of the bodies. A physically and chemically crosslinked gel, denoted as PEGDE/PEI-TAC/SMALA-Na (PPS), was designed and synthesized in a silicon carbide/carbon black aqueous slurry. This PPS gel imparted excellent mechanical properties to the bodies, manifested by high strain during the drying process and high strength after drying. These findings provide a new perspective for controlling the mechanical behavior of gelcast bodies through gel structure manipulation and achieving defect-free execution of the drying process in gelcasting.