High-Temperature Wear Behavior of Cobalt Matrix Composites Reinforced by LaF3 and CeO2

High-temperature wear of mechanical parts is still a challenge in many environments. Meanwhile, there is an imbalance between tribological properties and hardness of materials. In this work, high-temperature self-lubricating CoCrMo matrix composites containing the different contents of CeO2 and LaF3 were fabricated by powder metallurgy technology, and the effect of CeO2 and LaF3 on the microstructure and high-temperature tribological properties was evaluated. The tribological behavior of composites was conducted from RT to 1000 °C sliding against Si3N4 ball. The obtained results indicated that the hardness of materials increased by adding of solid lubricants. CeO2 and LaF3 greatly improved the tribological behavior of CoCrMo matrix composites from RT to 1000 °C. The results showed that a critical content of CeO2 and LaF3 existed for the optimum high-temperature friction and wear. The CoCrMo composite containing 7 wt% CeO2 and 7 wt% LaF3 showed the best tribological properties as compared with other specimens. The wear rate was measured to be on 10–5 mm3/N m order of magnitude, and it was 2–7 times lower than that of CoCrMo without solid lubricants. The reduction in wear rate was attributed to the combination of the high hardness, the solid lubricating effect of fluorides, chromates and molybdates.