Processing, characterization and tribological evaluation of peek-glass fiber composites

Abstract

This work reports the processing, characterization and tribological evaluation of a new class of composites with a polymer called poly-ether-ether-ketone as the matrix and glass fiber as the reinforcing material. Attempt is made to use red mud as filler in these fiber reinforced polymer matrix composites. Red mud is the solid waste generated in alumina plants during the production of alumina from bauxite by Bayer’s process. Characterization of the resulting red mud filled glass fiber reinforced polyether-ether-ketone composite is done. Silicon carbide is a known hard ceramic material. SiC powders are also filled in this glass fiber reinforced poly-ether-etherketone matrix and mechanical characterization of the resulting new composite is done. Solid particle erosion wear behaviour of this new class of composites is investigated. Erosion, an important material degradation mechanism encountered in a number of structural and engineering components, has been extensively investigated over the last few decades. However, the influence of factors like impact velocity, impingement angle, erodent size and stand-off distance (SOD) on erosion behavior of glass fiber reinforced polyether-ether-ketone composites is yet to be fully investigated. To this end, a design of experiment (DOE) approach based on Taguchi method is adopted in this work to evaluate effect of these factors on erosion rate of the composite. The study indicates that the rate of erosion of composites by impact of solid erodent is greatly influenced by these control factors. This work draws the conclusions that reinforcement of glass fiber into the poly-etherether-ketone ( PEEK ) matrix improves the flexural strength quite significantly, thus making it a potential material for structural applications. Addition of red mud and silicon carbide to glass fiber reinforced poly- ether-ether-ketone composites further improves the flexural strength, flexural modulus and tensile strength of the material. Addition of these fillers is leading to reduction of density and subsequently the strength to weight ratio of the composites. Glass fiber reinforced poly-ether-ether- ketone composites filled with red mud and silicon carbide powders exhibit much better resistance to solid particle erosion in comparison to the un-filled composite. The rate of wear of the composite material is also greatly influenced by operational variables like impact angle, velocity of impact, stand-off distance etc. and material variables like erodent size and composition of composites. These composites exhibited maximum erosion rate at an impingement angle of 60 0 under similar experimental conditions. The Taguchi experimental design approach suggests that the erodent size plays the most significant role in erosive wear of these composites. The angle of impact and the impact velocity are other major influencing factors. Stand-off distance has the least effect on the erosion rate. This work leaves a wide scope for future investigators to explore many other aspects of such composites. Wear of polyether-ether-ketone matrix composite has been a much less studied area. Many other problems like effect of fiber orientation, loading pattern, weight fraction of ceramic fillers on erosion response of such composites require further investigation. This work is expected to introduce a new class of functional polymer composites suitable for tribological applications.