Electromagnetic Interference Shielding Effectiveness of Pure SiC-TiSiC Composites Fabricated by Reactive Melt Infiltration.

Silicon carbide-based titanium silicon carbide (SiC-TiSiC) composites with low free alloy content and varying TiSiC contents are fabricated by two-step reactive melt infiltration (RMI) thorough complete reactions between carbon and TiSi alloy in SiC-C preforms obtained. The densities of SiC-C preform are tailored by the carbon morphology and volumetric shrinkage of slurry during the gel-casting process, and pure composites with variable TiSiC volume contents are successfully fabricated with different carbon contents of the preforms. Due to the increased TiSiC content in the obtained composites, both electrical conductivity and electromagnetic interference (EMI) shielding effectiveness improved progressively, while skin depth exhibited decreased consistently. The improvement in the EMI shielding effectiveness of the composite is due to the free electrons being bound to move in the conductive network formed by the TiSiC phase, converting electrical energy into thermal energy and reducing the energy of electromagnetic waves. Notably, at a TiSiC content of 31 vol.%, the EMI shielding effectiveness of the SiC-TiSiC composites in the X-band reached an impressive 62.1 dB, confirming that SiC-TiSiC composites can be treated as high-performance EMI shielding materials with extensive application prospects.