Tuned micron scale pore architectures enable high strength and low dielectric loss in porous β-SiAlON ceramics

Porous β-SiAlON ceramics are promising for high-frequency wave-transparent applications but are challenged by the balance between mechanical strength and dielectric performance. Herein, a Pickering emulsion assisted spontaneous coagulation route is used as a processing pathway to construct porous β-SiAlON ceramics with tunable micron scale pore architectures and reinforced load bearing skeletons. In this route, emulsion templating defines the spherical pore geometry, while mild room temperature consolidation provides sufficient green body integrity for subsequent reactive sintering. By regulating the Isobam content, solid loading and oil phase fraction, green bodies with uniformly distributed spherical pores of 5.43 – 14.81 μm were obtained, and the sintered ceramics exhibit a tunable open porosity of up to 42.93%. The optimized porous β-SiAlON ceramics achieve a compressive strength of 306.20 MPa and a flexural strength of 89.05 MPa, together with a low dielectric constant of 4.75 and a dielectric loss of 2.67 × 10-3 in the X band. This balanced mechanical and dielectric performance originates from the coordinated contribution of regulated micron scale pores for dielectric attenuation and a continuous ceramic skeleton for efficient load transfer. The present approach provides an effective pathway for designing structural-electromagnetic integrated porous ceramics.