Effect of densification parameters on the low-energy tribological behavior of carbon/carbon composites

The low-energy tribological behavior was investigated in carbon/carbon composites fabricated by processing with different densification parameters. In the densification process, different impregnating precursors and carbonization temperatures were used to investigate the influence on physical and mechanical properties, microstructure and tribological behavior. Experimental results indicate that the density and hardness of resin-based specimens are higher than those of pitch-based specimens after four densification cycles. When increasing carbonization temperature in the specimens based on coal tar pitch, the open porosity increases whereas both the bulk density and the hardness decrease. When comparing the tribological properties of the specimens with different impregnating precursors, coal tar pitch specimens show lower and more stable friction coefficients and exhibit lower weight losses. This is because the pitch matrix is transferred to the preferred orientation structure carbon after carbonization. The different carbonization temperatures do influence the tribological properties; specimens carbonized at 700 °C exhibit the lowest weight loss and the most stable friction coefficient.