TY - JOUR
T1 - Dielectric properties of Si 3N 4-SiCN composite ceramics in X-band
AU - Li, Quan
AU - Yin, Xiaowei
AU - Feng, Liyun
PY - 2012/9
Y1 - 2012/9
N2 - Si 3N 4-SiCN composite ceramics were successfully fabricated through precursor infiltration pyrolysis (PIP) method using polysilazane as precursor and porous Si 3N 4 as preform. After annealed at temperatures varying from 900 °C to 1400 °C, the phase composition of SiCN ceramics, electrical conductivity and dielectric properties of Si 3N 4-SiCN composite ceramics over the frequency range of 8.2-12.4 GHz (X-band) were investigated. With the increase of annealing temperature, the content of amorphous SiCN decreases and that of N-doped SiC nano-crystals increases, which leads to the increase of electrical conductivity. After annealed at 1400 °C, the average real and imaginary permittivities of Si 3N 4-SiCN composite ceramics are increased from 3.7 and 4.68 × 10 -3 to 8.9 and 1.8, respectively. The permittivities of Si 3N 4-SiCN composite ceramics show a typical ternary polarization relaxation, which are ascribed to the electric dipole and grain boundary relaxation of N-doped SiC nano-crystals, and dielectric polarization relaxation of the in situ formed graphite. The Si 3N 4-SiCN composite ceramics exhibit a promising prospect as microwave absorbing materials.
AB - Si 3N 4-SiCN composite ceramics were successfully fabricated through precursor infiltration pyrolysis (PIP) method using polysilazane as precursor and porous Si 3N 4 as preform. After annealed at temperatures varying from 900 °C to 1400 °C, the phase composition of SiCN ceramics, electrical conductivity and dielectric properties of Si 3N 4-SiCN composite ceramics over the frequency range of 8.2-12.4 GHz (X-band) were investigated. With the increase of annealing temperature, the content of amorphous SiCN decreases and that of N-doped SiC nano-crystals increases, which leads to the increase of electrical conductivity. After annealed at 1400 °C, the average real and imaginary permittivities of Si 3N 4-SiCN composite ceramics are increased from 3.7 and 4.68 × 10 -3 to 8.9 and 1.8, respectively. The permittivities of Si 3N 4-SiCN composite ceramics show a typical ternary polarization relaxation, which are ascribed to the electric dipole and grain boundary relaxation of N-doped SiC nano-crystals, and dielectric polarization relaxation of the in situ formed graphite. The Si 3N 4-SiCN composite ceramics exhibit a promising prospect as microwave absorbing materials.
KW - C: Dielectric property
KW - D. Si N
KW - D. SiC nano-crystal
KW - Polymer derived ceramics
UR - http://www.scopus.com/inward/record.url?scp=84862683286&partnerID=8YFLogxK
U2 - 10.1016/j.ceramint.2012.03.045
DO - 10.1016/j.ceramint.2012.03.045
M3 - 文章
AN - SCOPUS:84862683286
SN - 0272-8842
VL - 38
SP - 6015
EP - 6020
JO - Ceramics International
JF - Ceramics International
IS - 7
ER -