Effect of Adding Graphite Powder to a UP Polymer on Friction and Wear for Different Loads and Rubbing Speeds

Abstract

The aim of the present work is the investigation of the influence of graphite powder addition to an unsaturated polyester type polymer (32% styrene content in mass) on the mechanical and tribological properties. For this purpose, we conducted bending tests and wear tests with a combination of four loads and three speeds for three different compositions (0, 1 and 2% graphite). The wear tests are carried out on a dry type pin on disk tribometer. The disk is made of quenched and annealed C48 steel (540 Hv hardness). Before the rubbing process, the discs are subjected to polishing in order to obtain approximately the same initial surface roughness. The results show that the addition of graphite powder improves the tribological properties; a noticeable decrease of the coefficient of friction, the mass loss and the wear rate are achieved with the increase of the graphite powder percentage for all sliding speeds and loads. A 2% graphite content causes a drop of the friction coefficient from 0.4 to 0.2. The results of bending tests showed a significant decrease of the stress and strain at failure and a slight increase in Young's modulus. In addition, for the three compositions, the results show a clear preponderance of the influence of the load on the tribological properties.

Abrasive wear performance of multi-layer interwoven polyester fiber & PTFE particle reinforced polyester composite

“…23 Previous studies with a tribological point of view on polyester composites report improvement in fatigue and tensile strength. Moreover, some researches reported reducing friction and wear rate abilities of thermoset polyesters thanks to self-lubricating additives as graphite powder 24 and clay. 25 When various descriptive studies of the wear behavior of polyester matrix composite materials are examined, it is ensured that the reinforcement materials have typically increased the wear resistance in general.…”