Dry Friction and Wear of Graphite-Filled PTFE Composites using Taguchi Approach

Composite plain-bearing specimens with a porous structure were produced from spherical bronze powders (100–200 µm) using sintering technology. Pure Polytetrafluoroethylene (PTFE) and PTFE composites were then impregnated into the porous bronze structure and coated onto the surface. The PTFE mixtures were reinforced with graphite particles, with the graphite powder (average particle size: 200 µm) incorporated into the PTFE solution at varying ratios. This process was applied using the spray coating technique. Wear experiments were conducted based on a design created using the Taguchi method. The experimental parameters were optimized using the L27 Taguchi orthogonal array to achieve optimal friction coefficient and wear loss. The results showed that the experimental and verification test results were highly consistent. The material type/graphite content had the most significant impact on the friction coefficient and wear loss (71.6% and 30.88%, respectively). Sliding speed had the greatest effect (55.06%) on bearing temperature. Elemental analysis and chemical characterization of the composite plain bearing specimens were conducted using Energy Dispersive Spectroscopy (EDS). The wear surfaces were examined via Scanning Electron Microscope (SEM).The study concluded that the most significant factor affecting bearing wear is the material type. The 10% graphite additive, which reduces friction in the material, yielded optimal results in the study. An increase in sliding speed leads to a rise in bearing temperature, which in turn accelerates wear. Compared to industrially used bearings, the study found that more graphite lubricant was impregnated into the pores of bronze, and the optimal 10% additive provided a positive advantage in wear performance.