Wave-absorbing porous ceramics from lead–zinc tailings and its synergistic regulation of multiscale properties

In this study, the structure‒property relationships of lead‒zinc tailing-based porous ceramics prepared via gel-casting were systematically investigated, with a focus on the influence of solid loading. Rheological characterization revealed a dual-stage transition from shear-thinning to shear-thickening within a shear rate range of 0–120 s⁻¹. Microstructural analysis revealed that increasing the solid loading significantly reduced the interparticle spacing, promoted sintering densification and homogenized the pore size distribution. At a solid loading of 50 vol%, the optimal pore topology (fractal dimension D = 1.382, pore shape factor R = 1.242) corresponds to a maximum Weibull modulus of 26.15, confirming a highly uniform defect distribution. Further analysis revealed enhanced dielectric responses: the real permittivity increased from 2.441 to 3.768, whereas the dielectric loss tangent increased from 0.06703 to 0.1692, which intensified the interfacial polarization and defect-induced conduction loss. In the X-band (8.2–12.4 GHz), the ceramics demonstrated exceptional electromagnetic wave attenuation performance. When the solid loading is 50–55 vol%, the minimum reflection loss (RL_min) reaches –29.39 dB (50 vol%) and –46.44 dB (55 vol%), with effective absorption bandwidths (RL ≤ –10 dB) of 4.2 and 4.0 GHz, respectively. This performance optimization stems from synergistic impedance matching and multimechanism energy dissipation.