A digital light processing 3D printing of TPMS variable density β-SiAlON/BN composite ceramics for enhancing wave transmission

DLP 3D printing facilitates the fabrication of complex 3D porous architectures, thereby effectively enhancing the wave transmission performance of ceramics, but achieving uniform curing of multiple components in the ceramic slurry remains a critical challenge. The β -SiAlON/BN composite ceramics were prepared via surface modification of different ceramic powders, fabrication of photosensitive ceramic slurries, DLP 3D printing, and subsequent sintering treatment. Surface modification via the reaction of tetraethyl orthosilicate (TEOS) with the surfaces of different ceramic powders, which leverages its hydrolysis and condensation properties to uniform silica coating on the powder surfaces. A multi-component photosensitive ceramic slurry, thus prepared via this modification, exhibits both high curing depth and low viscosity, thereby overcoming the uneven curing issue during exposure of multi-component photosensitive ceramic slurries and enhancing the curing depth of non-oxide ceramics including Si 3 N 4 and AlN. The mechanical and dielectric properties of β -SiAlON/BN composite ceramics with varying h-BN contents were systematically investigated. When the h-BN content was 5 wt%, the composite ceramic exhibited a flexural strength of 254.45 MPa, and the dielectric constant ( ε ) was significantly reduced to 3.1 within the 8.2–12.4 GHz frequency band. The diamond-type triply periodic minimal surface (TPMS) structure was modified with a trigonometric function-based variable density gradient design for the fabrication of complex porous ceramics. When the offset value ranged from −0.5 to 0, the shorter the function period, the smaller the ε of the structure, with the minimum ε decreasing to 2.15. These findings provide theoretical and technical references for lightweight structural design of wave-transparent ceramics, demonstrating broad prospects for high-performance applications such as radar systems, missiles, radomes, and antenna windows.