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.

Preparation and Characterization of Pure SiC Ceramics by HTPVT Induced by Seeding with SiC Nanoarrays.

Dense SiC ceramics were fabricated by high-temperature physical vapor transport (HTPVT) growth process using SiC nanoarrays as the crystal seeds, which was obtained by vacuum heat treatment of amorphous SiC films prepared by plasma-enhanced chemical vapor deposition (PECVD) with a porous anodic aluminum oxide (AAO) template. In the HTPVT process, two-step holding was adopted, and the temperature at the first step was controlled at 2100 and 2150 °C to avoid SiC nanoarrays evaporation, and the grain size of SiC crystal increased with the increase in temperature and decrease in the pressure of Ar. The temperature of the second step was 2300 °C, and rapid SiC grain growth and gradual densification were achieved.