Improving the microwave dielectric properties of Ti3SiC2 powders by Al doping

•Al-doped Ti3SiC2 powders with higher purity were synthesized by solid state reaction.•20% Al-doped Ti3SiC2 sample showed the greater values in ε′ and ε″ than undoped one.•20% Al-doped sample had the better reflection loss with a thinner absorbing thickness.•The mechanism of microwave dielectric loss improved by Al doping was discussed.

Al-doped Ti3SiC2 powders were synthesized by solid state reaction under a vacuum atmosphere. Results showed that Al doping effectively improved the purity of the as-prepared Ti3SiC2 powders which had a narrow particle size distribution. The complex permittivities and reflection loss of Ti3SiC2 samples were determined in the frequency range of 8.2–12.4 GHz. It was found that 20% Al-doped sample showed the greatest values in the real part ε′ and imaginary part ε″ of complex permittivity and the better reflection loss with an absorbing thickness of 2.1 mm. The mechanism of dielectric loss by Al doping was discussed.