Influence of oxidation on the dielectric and microwave absorption properties of the milled Ti3SiC2 powders

Ti3SiC2 powders with different characteristics were obtained by ball milling. The particle size decreased and the powder morphology changed from lamellar to flaky with the increasing milling time. As the milling time increased from 5 h to 20 h, the complex permittivity of Ti3SiC2 powders was enhanced and the absorption peak shifted toward the lower frequency range. The dielectric and microwave absorption properties of the Ti3SiC2 powders oxidized at high temperature were also investigated. The Ti3SiC2 powders milled for longer time were more easily oxidized because of the increasing surface area. The lamellar Ti3SiC2 powders were delaminated after oxidation at high temperature due to the mismatch of thermal expansion coefficients. The oxidation products (TiO2 and SiO2) formed on the surface slowed down the oxidation process of Ti3SiC2 powders. The complex permittivity and microwave absorption properties of Ti3SiC2 powders were decreased as the temperature raised from 25 degrees C to 700 degrees C. (C) 2015 Elsevier B.V. All rights reserved.