Tribological properties of oil palm fiber-derived graphene coatings on piston ring; influence of hydrogen flow rate during CVD process

This study aims to investigate the influence of varying hydrogen flow rates on the tribological properties of graphene-coated piston rings developed via chemical vapor deposition (CVD) with oil palm fiber as precursor. Graphene was derived from oil palm fiber and polystyrene with varying Hydrogen (H₂) flow rate in the CVD process i. e, 200, 400, 600 and 800 sccm and deposited on piston rings. The tribological tests were conducted using a high-frequency reciprocating rig (HFRR) according to ASTM G181 – 11 engineering standards. The load of 10N was kept constant for each test and the test was performed till 300m sliding distance was attained. Among all four hydrogen flow rates, it was observed that graphene-coated piston ring developed with 600 sccm and 800 sccm hydrogen flow rates show enhanced tribological properties when derived from 100 wt% of oil palm fiber and polystyrene respectively. The coated piston ring results were compared with non-coated commercially used piston rings and it was found that the coefficient of friction and wear rate of 600 sccm oil palm fiber based graphene coated piston ring was reduced by 20 % and 70 % respectively as compared to uncoated piston ring.