Symmetric Gradient-Structured Sicnws Modified Sic/Si3n4 Composites Toward Enhanced Thermal Stability, Absorption Power and Electromagnetic Interference Shielding

Abstract

In this study, to optimize electromagnetic interference shielding performance and achieve high absorption power, different SiCnws contents (4.99, 10.23, and 15.85 wt%, corresponding to specimens SN1, SN2, and SN3) and a symmetric gradient structure (SN4) were incorporated into SiC/Si3N4 composites. The findings revealed that increasing the SiCnws content significantly enhanced the total shielding efficiency (SET) and reflection power of the composites in the X-band. Compared to SiC/SiC composites, the SET and absorption power of SN3 increased from 30.56 dB and 0.121 nW to 57.56 dB and 0.160 nW, respectively. Although the V of SN4 (51.97 dB) was slightly lower than that of SN3, it exhibited the highest absorption power (0.309 nW). Relative to the SiC/SiC composites, the SEA and absorption power increased by 113.7% and 155.4%, respectively. Importantly, this composites exhibited excellent thermal stability, maintaining superior shielding performance after oxidation at 1100 °C for 2 h, with a high SET of 48.60 dB and an absorption power of 0.316 nW. Additionally, the composites demonstrated a bending strength of 152.7 ± 11.3 MPa. In summary, the SiCnws modified SiC/Si3N4 composites provides excellent shielding performance, high absorption capacity and adequate mechanical properties.

Keywords: SiC/SiCnws-Si3N4 composites, symmetric gradient structure, shielding effectiveness, thermal stability, bending strength