Comparative Study on the Wear Behaviour of Two High-Temperature-Resistant Polymers

The wear behaviour of two kinds of high performance polymers, i.e. polyetheretherketone (PEEK) and polybenzimidazole (PBI) was investigated at room and elevated temperatures (up to 175 degrees C). The results showed that PBI possessed better wear resistance than PEEK when the temperature was lower than 70 degrees C, which can be explained by the excellent thermal mechanical properties of PBI. However, PEEK showed even higher wear resistance when temperature is above 140 degrees C. It was noted that the formation of an effective TFL plays a key role in determining the wear performance of the polymer/steel system. In particular, the relatively low wear rate for PEEK achieved at elevated temperatures when the "transfer film efficiency factor'' was clearly larger than one, although the mechanical properties of PEEK were significantly degraded. This means that under these conditions, the wear process of the polymer would be governed by the damage and regeneration process of the TFL at the interface rather than the bulk properties of the polymer specimen. The selection of high performance polymers for high wear resistance needs to consider not only their thermal mechanical properties, but also the possible wear regime(s) under the sliding conditions in the required applications.