Si3N4 ceramics with embedded microchannel structures fabricated by high-precision additive manufacturing based on computational fluid dynamics simulations

Abstract

Ceramics with microchannel structures are primarily used in heat exchangers and microfluidic device applications in harsh environments, such as high-temperature and corrosive conditions. However, the high cost the difficulty of fabrication limits the development of microchannel ceramics, especially the embedded microstructures. Here, a strategy of fabricating the Si 3 N 4 ceramics with embedded microchannel structures by material extrusion is reported. We employ the finite element method to analyze the computational fluid dynamics (CFD) model of the material extrusion process with a pressure-actuated system, and the simulation results are validated by comparing with the experimental average flow velocity under different air pressures. Due to the accurate prediction of the flow rate and the excellent shape-retention of Si 3 N 4 inks, the shape and size of the filaments are controllable. Therefore, microchannel structures with a size of 0.09 – 0.94 mm were fabricated by different nozzles, and the flow direction and the channel density can be freely designed by the printing paths. Our results provide guidelines of setting parameters for accurately printing the structures as designed.