Assessment of the tribological performance of glass fibre reinforced polyamide 6 under harsh abrasive environments

Abstract

High-performance thermoplastics exhibit significant potential to substitute metals in various applications, primarily due to their remarkable tribological, thermal and mechanical characteristics. Nevertheless, their characteristics require further refinement. This research aims to assess and compare the influence of distinct material types on the tribological characteristics of Polyamide 6 composites, as well as their reliance on the PV factor, which is the result of the velocity and pressure product.In the current research, the friction and wear performances of polyamide 6 (PA6) reinforced with glass fibres were examined in adverse PV factors till materials failed. Twin screw extrusion and subsequent injection moulding procedures were utilised to process the materials. The tribo-performance of the materials was assessed in ambient conditions using a pin-on-disc abrasive configuration. The morphological analysis of the abraded surfaces was conducted through field emission scanning electron microscopy (FESEM), and the plausible wear mechanisms contributing to wear are explained. Furthermore, the materials were thoroughly characterised for their tribological, mechanical and physical behaviours.The wear behaviour depended mainly on operating parameters and composition. PA6 proved to be beneficial till moderate PV conditions but not for harsh operating environments as compared to PA6 reinforced with 25% by volume of glass fibres (PA625GF). PA625GF showed PVlimit value of 1.04 MPa m/s which was decisively superior to PA6 (0.78 MPa m/s). Additionally, under a load of 50 N, PA625GF could sustain a higher speed of 800 rpm as compared to PA6 (600 rpm). The results showed that under all testing conditions glass fibres can minimise the coefficient of friction. Under low PV settings, the specific wear rate of PA625GF was remarkably reduced owing to the presence of glass fibres, reflecting superior anti-wear properties. Notably, the wear resistance of PA6 was considerably improved by glass fibres, particularly under high PV conditions, resulting in a PVlimit of 1.04 MPa m/s. The enhancement in PVlimit was attributed to the protective function of the fibres on the matrix and their superior mechanical properties. PA625GF proved to be tribo-potential materials in abrasive wear mode under extreme conditions in terms of low specific wear rate (8.484 ×10−3 mm3/N.m) and PVsafe value (0.78 MPa*m/s). This study is expected to pave the way for the development of novel self-lubrication composite materials for harsh service environments.