Effects of particle sizes and contents of ceramic fillers on tribological behavior of 3D C/C composites

Ceramic fillers of different types and sizes were introduced into three-dimensional needled integrated fiber felts by one shot infiltration to produce ceramic modified carbon/carbon (C/C) composites. The mass contents of SiC filler with particle sizes of 1.0 and 5.0 μm were about 18% and 13%, respectively; those of B₄C filler with particle sizes of 1.5 and 5.0 μm were about 16% and 12%, respectively. The densities of these modified composites, except large-sized B₄C filler modified C/C composite, were in the range of 1.60-1.70 g/cm³. Small-sized B₄C filler and small-sized SiC filler modified C/C composites had higher coefficients of friction (COF) of 0.37 and 0.32 and lower wear rates of 2.03 and 2.05 μm side^-1 cycle^-1, respectively, under the braking velocity, pressure, and inertia of 28 m/s, 0.85 MPa, and 0.235 kg m ² respectively. For 50 braking cycles, the COF of these two composites had the lowest fluctuation (-0.01 to 0.01) relative to the average values. The frictional performance of these modified composites, except large-sized B₄C filler modified C/C composite, was negligibly affected by wet environments.