Improvement of mechanical and dielectric properties of PIP-SiC_f/SiC composites by using Ti₃SiC₂ as inert filler

In order to optimize the mechanical and dielectric properties of SiC_f/SiC composites, Ti₃SiC₂ was introduced into the composites by a modified precursor infiltration and pyrolysis (PIP) process. The results reveal that the appropriate Ti₃SiC₂ content in the infiltration precursor can effectively enhance the infiltration efficiency and decrease the open porosity of SiC_f/SiC composites. The maximum flexural strength of the composites reaches 273 MPa when the Ti₃SiC₂ content is 9 wt%, which is 131% higher than that of the composites without filler (118 MPa). This is mainly attributed to the high density and suitable interfacial bonding of the composites with the Ti₃SiC₂ filler. Both the ε′ and ε″ values of SiC_f/SiC composites show a monotonically increasing tendency from 13.5-16.5 and i15-i19 to 27.5-32.5 and i31.5-i39 with the Ti₃SiC₂ content increase from 0 to 15 wt%. Especially, the conductivity and complex permittivity of the composites display a relative large increasing extent for Ti₃SiC₂ content exceeding 9 wt% owing to the percolation threshold effect.