Influences of milling on the dielectric and microwave absorption properties of Ti3SiC2/cordierite composite ceramics

Cordierite ceramics doped with Ti3SiC2 powders milled for different time are fabricated by hot pressed sintering process. For the Ti3SiC2 powders, the particle size is decreased and the morphology is changed from lamellar to flaky with the increasing milling time. The finer Ti3SiC2 particles are detrimental to the densification process but favorable to the improvement of flexural strength of the full dense ceramics. Dielectric and microwave absorption properties of the ceramics are investigated in the frequency range of 8.2-12.4 GHz. As the milling time increases, both the real and imaginary part of the complex permittivity are enhanced which is attributed to the decrease of particle size and formation of flaky particles. The ceramic doped with Ti3SiC2 powders milled for 10 h presents the optimal microwave absorption property. The effective absorption bandwidth (RL < −10 dB) with a minimal RL value of −16.4 dB is obtained in 9.7-12.4 GHz for the ceramic in 1.6 mm thickness.