Erosive and sliding wear of polybenzimidazole at elevated temperatures

Polybenzimidazole (PBI) is the most sought polymer for high thermal stability, mechanical strength and retention at elevated temperatures. However, its potential for tribological applications, especially at high temperatures and under various wear modes, is not yet explored in depth. In this work, commercially available PBI was investigated under sliding wear against steel at elevated temperatures and different pressures. A relation between the linear wear rate and the test temperature could be shown. But the wear mechanisms do not differ very much within the temperature range tested. In addition, the solid particle erosion resistance of PBI under different impact angles and surface finishes was investigated at ambient and high temperature. A higher erosion rate took place when the temperature was increased. Overall, PBI showed a semi-brittle erosive failure (alpha (max) at 45A degrees) behaviour. Scanning electron microscopy was used to understand the wear mechanisms in more detail, and white light profilometry allowed to get information about the topography of the fresh and eroded surfaces.