Abstract：Transmission spectra of SiC and Si₃N₄powders in 0.42.4 THz were measured using terahertz time-domain spectroscopy.The relationship between the terahertz waves absorption performance and the conductivity of SiC and Si₃N₄ powders was studied.The terahertz waves scattering characteristics of SiC and Si₃N₄ powders were analyzed.The results indicate that the terahertz waves absorption performance of SiC powders is higher than that of Si₃N₄powders,because SiC is a kind of semiconductor materials in which there are much more free carriers than Si₃N₄.The terahertz waves scattering of SiC and Si₃N₄ powders belongs to Rayleigh scattering.But the scattering effect is not obvious because of the big gap between the wavelength of terahertz waves and the particle sizes of SiC and Si₃N₄powders.

Keywords：terahertz wave;terahertz time-domain spectroscopy;absorption;conductivity;scattering