The effects of the hydraulic oil on mechanical and tribological properties of C/C composites

Effects of the hydraulic oil on mechanical and tribological properties of C/C composites are studied. The results showed that the flexural strength and flexural modulus of the oil-adsorbed composites decreased by 15.2% and 10.9%, respectively, compared to those of the oil-free composites. The decrease on the strength was caused by the deterioration of fiber-matrix interface due to the oil burning. Braking test was performed for 100 cycles. The oil-adsorbed composites had a low friction coefficient (μ) ranging from 0 to 0.18 in the initial six tests for the waste of oil. From the seventh braking test, μ increased to values ranged from 0 to 0.38 which were still lower than those of the oil-free composites (μ = 0–0.45); the lower value of μ is caused by the remaining oil and the formation of carbon film in the oil-adsorbed composites even though the composite had 100 braking tests.