CANCELED - High performance tribo-composites for severe operating conditions

J.N. Panda, J. Bijwe, R.K. Pandey
Indian Institute Of Technology, Delhi, India,
India

Keywords: polymer, PAEK, tribology, PV limit, composite

Summary:

Advanced polymer composites reinforced with fibers have potential applications in almost every field due to their remarkable features like extraordinary mechanical, thermal, and tribological properties. To maximize the performance of such composites, the selection of type and amount of matrix, reinforcement (its form such as fibers, fabric, and aspect ratio), fillers/solid lubricants, and processing technique becomes most crucial parameters. In this study, two composites based on polyaryl ether ketone (PAEK) (50 and 60 wt. %%) filled with short glass fibers (SGF) (30%) and a solid lubricant (graphite powder) in two amounts (20% and 10%) were developed and investigated for physical, mechanical and tribological performance. In particular, tribological properties as functions of graphite content (10% and 20%), applied load (700-900N) and sliding speeds (1.63-5.5 m/s) were systematically investigated on a pin on disc (mild steel) configuration under dry condition. The incorporation of 20 wt.% graphite (K20) led to the specific wear rate (K0) 2-4 x 10-16 (m3/Nm) while the coefficient of friction (µ) 0.04-0.06 and 10 wt.% graphite (K10) showed (K0) 5.7-1.6 x 10-16 (m3/Nm) and µ 0.07-0.04. The results also demonstrated a slightly increased modulus and thermal stability but remarkable increased strength, micro hardness etc. for K20. During evaluation for investigating PVlimit values (pressure x velocity), K20 (154 MPa-m/s) proved decisively superior to K10 (112 MPa-m/s). K20 could sustain higher speed (5 m/s) than the K10 (3.75 m/s) under 900 N with 12 km sliding distance. This was highly associated with the formation of high-quality transfer film on the mild steel counterpart surface as evident from SEM (Scanning electron microscopy) and EDAX (Energy dispersive X-ray) analysis of the transfer film on the worn surfaces. This study confirmed the high efficiency of using graphite to reinforce PAEK polymer for tribological applications.