Effect of bimodal particle size distribution on the performance of SiC slurry for maskless vat photopolymerization

To address the concerns associated with the difficulties of the very limited light curing depth in the pure silicon carbide (SiC) printing slurry, a bimodal particle size distribution was investigated systematically. Powder mixtures of 1 µm SiC particles and 10.5 µm SiC particles with specific ratios were prepared for making the printing slurries of 55 vol% solid load. A comprehensive investigation was conducted on the rheological stability and photopolymerization properties of coarse and fine powders at different proportions, along with an exploration of the impact of powder proportion on the quality of sintering. It was observed that at a 40% proportion of fine powder in the mixed powder, the viscosity of the slurry reached its minimum value (4.7 Pa.s) at a shear rate of 10 s–1. Meanwhile, the settlement ratio V1/V0 reached the lowest value of 1.2%. The printed sample size closely matched the design size and the quality of ceramic samples obtained after sintering was excellent (134.78 MPa).