Optimized microwave absorption properties for TiB2@BN/PDMS composites by constructing TiB2@BN heterogeneous interface

The single electromagnetic (EM) wave loss mechanism leads to suboptimal microwave absorption in dielectric loss materials. However, introducing different materials and constructing distinctive microstructures can significantly improve microwave absorption. Herein, Titanium diboride (TiB2) and TiB2@BN powders were synthesized via the boron thermal reduction and chemical solution methods. The microwave absorption and thermal properties of TiB2/polydimethylsiloxane (PDMS) and TiB2@BN/PDMS composites were investigated. Compared to TiB2/PDMS, TiB2@BN/PDMS composites achieve enhanced microwave absorption across the 2–18 GHz. The minimum reflection loss (RLmin) reaches -31.2 dB at 17.92 GHz with 60 wt% TiB2@BN and a thickness of 1.55 mm. RL below -10 dB covers the frequency range of 12.88–18 GHz with 65 wt% TiB2@BN and a thickness of 1.75 mm. Radar cross-section (RCS) simulations show notable stealth capabilities, making it suitable for practical applications. Establishing the TiB2@BN heterointerface can optimize impedance matching and electromagnetic wave attenuation, thereby enhancing microwave absorption. Charge transfer from B and N atoms to Ti atoms, combined with lattice defects, generates strong interface and dipole polarization loss under an external EM field. Additionally, TiB2@BN/PDMS composites possess excellent thermal conductivity. These results highlight the potential of TiB2@BN/PDMS composites in advanced microwave absorption and thermal management applications