Effect of ISOBAM content in slurry on preparation, microstructure, and mechanical properties of SiC ceramics fabricated by combining direct ink writing and liquid silicon infiltration

Abstract

SiC ceramic materials were prepared using a combination of direct ink writing (DIW) and liquid silicon infiltration (LSI). In this study, we investigated the effects of the content of a copolymer of isobutene and maleic anhydride (ISOBAM) on the rheological properties of the slurry, microstructure of green bodies and SiC ceramics, and bending properties of SiC ceramics. ISOBAM significantly improved the rheological properties of the slurry and formability of the SiC green body. The yield stress and equilibrium modulus of the slurry without ISOBAM were 160.3 Pa and 1.12 × 105 Pa, respectively, and increased to 607.7 Pa and 2.37 × 106 Pa, respectively, after the addition of 0.46 wt% ISOBAM. LSI was effective in improving the density of the green body, and the densities of the sintered SiC ceramic materials ranged from 2.71 to 2.86 g/cm3. The bending strength of SiC ceramic materials initially increased and then decreased when the ISOBAM addition increased from 0.15, to 0.30, and 0.46 wt%, and the slurry with 0.30 wt% ISOBAM exhibited the highest bending strength of 287.7 ± 9.1 MPa.