TY - JOUR
T1 - Induced crystallization behavior and EMW absorption properties of CVI SiCN ceramics modified with carbon nanowires
AU - Xue, Jimei
AU - Yin, Xiaowei
AU - Cheng, Laifei
N1 - Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/12/15
Y1 - 2019/12/15
N2 - Herein we reported on the crystallization mechanism and electromagnetic wave (EMW) absorption properties of in-situ carbon nanowires (CNW) modified amorphous SiCN ceramics. The composite ceramics were prepared by catylitic chemical vapor deposition (CCVD) CNW and chemical vapor infiltration (CVI) SiCN on porous Si3N4 matrix, forming Si3N4-CNW-SiCN composite ceramics with sandwich structure. The high specific area and unique microstructure of CNW have been shown to significantly affect the crystallization behavior and composition of the composite ceramics during heat-treatment. Furthermore, both complex permittivity and electrical conductivity of Si3N4-CNW-SiCN composite ceramics firstly increased and then decreased with the increase of annealing temperature, because carbon nanotubes (CNTs) with higher electrical conductivity were formed with the help of catalytic Ni at the temperature of 1200 °C, and then SiCN ceramics was gradually crystallized into graphite, β-SiC and α-Si3N4 ceramics with lower electrical conductivity at the higher temperatures. The completely crystallization temperature of Si3N4-CNW-SiCN composite ceramics was about 1400 °C compared with 1600 °C of Si3N4-SiCN.
AB - Herein we reported on the crystallization mechanism and electromagnetic wave (EMW) absorption properties of in-situ carbon nanowires (CNW) modified amorphous SiCN ceramics. The composite ceramics were prepared by catylitic chemical vapor deposition (CCVD) CNW and chemical vapor infiltration (CVI) SiCN on porous Si3N4 matrix, forming Si3N4-CNW-SiCN composite ceramics with sandwich structure. The high specific area and unique microstructure of CNW have been shown to significantly affect the crystallization behavior and composition of the composite ceramics during heat-treatment. Furthermore, both complex permittivity and electrical conductivity of Si3N4-CNW-SiCN composite ceramics firstly increased and then decreased with the increase of annealing temperature, because carbon nanotubes (CNTs) with higher electrical conductivity were formed with the help of catalytic Ni at the temperature of 1200 °C, and then SiCN ceramics was gradually crystallized into graphite, β-SiC and α-Si3N4 ceramics with lower electrical conductivity at the higher temperatures. The completely crystallization temperature of Si3N4-CNW-SiCN composite ceramics was about 1400 °C compared with 1600 °C of Si3N4-SiCN.
KW - Crystallization behavior
KW - Dielectric properties
KW - EMW absorption properties
KW - SiN-CNW-SiCN composite ceramics
UR - http://www.scopus.com/inward/record.url?scp=85068914329&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2019.122213
DO - 10.1016/j.cej.2019.122213
M3 - 文章
AN - SCOPUS:85068914329
SN - 1385-8947
VL - 378
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 122213
ER -