One-step arc synthesis and enhanced microwave absorption performances of Al-doped SiC nanoparticles

Here, a facile one-step arc-discharge method was applied to synthesize the Al-doped SiC nanoparticles. Compared to undoped SiC, the shifts of bound-hole around Al-Si defects in the Al-doped SiC crystal at the alternating electromagnetic field from one equilibrium position to another must overcome a potential barrier, producing forceful relaxation polarization. Meanwhile, the abundant defects caused by Al doping in Al-doped SiC nanoparticles not only act as polarization centers contributing to the enhanced polarization loss but also create more current carriers increasing the leakage loss. Furthermore, the weak magnetism caused by the Al-Si defects can further optimize the balance of dielectric loss and magnetic loss and achieve a better impedance matching for Al-doped SiC nanoparticles. Therefore, Al-doped SiC nanoparticles have the enhanced microwave absorption capacity, which exhibits the minimum reflection loss (RL) value of - 43.7 dB at a thickness of 3 mm and RL below - 10 dB covered 3.2-18 GHz with the changeable thickness of 1.22-5.5 mm. This work provided a defect-engineering strategy in modifying SiC-based high-temperature dielectric ceramics of microwave absorption performances.

Automated summary

Al-doped SiC nanoparticles were synthesized using a one-step arc-discharge method, demonstrating enhanced microwave absorption capacity with lower reflection loss values and wider coverage range. This defect-engineering strategy provides insights for modifying SiC-based high-temperature dielectric ceramics for improved microwave absorption performances.