Influence of fiber direction on the tribological behavior of carbon reinforced PEEK for application in gas turbine engines

Abstract

The conditions under which materials are expected to perform in the next generation of gas turbine engines are becoming increasingly challenging. Consequently, proper material selection is essential for extending the service life of engine components. Polymer matrix composites (PMCs) offer an alternative to traditional metals and alloys due to their high strength-to-weight ratios; however, their use in harsh environments is still limited. Previous studies have extensively characterized carbon-reinforced polymer composites, highlighting the effects of parallel and anti-parallel fiber orientations on their mechanical properties and tribological behavior. However, recent advancements in PMC manufacturing have enabled the production of carbon-reinforced polyetheretherketone (PEEK) with fibers oriented normal to the surface. While this innovative technology shows promise with respect to mechanical properties, the tribological behavior of PMCs featuring normal fiber orientation has not been thoroughly investigated. This study aims to enhance the understanding of how fiber orientation influences the tribological performance of carbon-reinforced polymers. Friction and wear tests were conducted on CF-PEEK films with fibers aligned in the normal direction, and the results were compared to those of standard modulus carbon fiber/PEEK unidirectional tape (UD) and unreinforced, pure PEEK films under various contact conditions. Worn surface characterization was performed through ex situ analysis, utilizing techniques such as scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and atomic force microscopy (AFM) to reveal interfacial phenomena. A correlation between fiber orientation and wear and friction performance was established based on the different experimental parameters.