Vat photopolymerization 3D printed SiOC-based metamaterials with triply periodic minimal surface: Microwave absorption and load-bearing properties

Microwave absorbing structures are important for addressing challenges in complex electromagnetic (EM) and physical environments because they offer broadband absorption, a lightweight design, and mechanical load-bearing capabilities. Herein, this work employed vat photopolymerization 3D printing and polymer-derived ceramics (PDCs) technology to manufacture Re₂O₃-modified SiOC metamaterials, where Re refers to holmium (Ho), neodymium (Nd), and yttrium (Y). The materials feature a triply periodic minimal surface (TPMS) meta-structure inspired by the gyroid structure. The effects of different Re elements on the dielectric, magnetic, microwave absorption, and compression properties were investigated. Compared with the original SiOC, Ho₂O₃[sbnd]SiOC, and Y₂O₃[sbnd]SiOC ceramics, the Nd₂O₃[sbnd]SiOC ceramic demonstrated excellent absorption characteristics within the X[sbnd]band. It achieves a minimum reflection loss (RL_min) of [sbnd]45.12 dB at 4.15 mm and an effective absorption bandwidth (EAB) spanning 4.2 GHz from 3.5 to 3.7 mm. This performance is attributed mainly to the TPMS meta-structure, which improves impedance matching. The Nd₂O₃ particles enhance the dielectric and magnetic losses. The Nd₂O₃[sbnd]SiOC ceramic also demonstrated strong mechanical properties, with a maximum failure strength of 11.3 MPa and a Young's modulus of 1.72 GPa. These results arise from the uniform dispersion and fine-scale distribution of Nd₂O₃ within the SiOC matrix. The CST simulations indicate that the Nd₂O₃[sbnd]SiOC metamaterials cover the entire C-band (4–8.2 GHz), which is particularly effective within thicknesses ranging from 2.9 to 5.0 mm. Consequently, Nd₂O₃[sbnd]SiOC ceramics display substantial promise in both their low-frequency and broadband absorption capabilities, as well as in their mechanical load-bearing properties.