The study of the microwave absorption property of the Al and N codoped SiC Nanopowders

摘要

Nanopowders of aluminum and nitrogen codoped fl-silicon carbide (P-SiC) were successfully produced by self-propagating high-temperature synthesis (SHS) in a nitrogen atmosphere. Characterizations by X-ray diffraction and scanning electron microscopy demonstrate the formation of Al-N codoped P-SiC nanopowders. In 1 MPa N_2 atmosphere, the X-ray analysis of the produced powders suggests that Al and N are accommodated in the lattice of SiC, which enlarges with increasing amounts of Al. The electric permittivities of prepared powders have been determined in the frequency range of 8.2-12.4 GHz. Al and N codoping results in the increase of the electric permittivities of SiC, compared to the undoped SiC. With the increasing the amounts of Al, the electric permittivities of the Al and N codoped SiC nanopowders are increased. The paper presents a method to adjust dielectric property of SiC powders in the GHz range. These features confer Al-N codoped p-SiC qualifications of the important microwave absorbing material.