The effect of corrosive environment on mechanical and wear properties of graphene filled basalt/epoxy nanocomposites

The effects of graphene nanoplatelet (GNP) additive on the mechanical and tribological properties of basalt fiber reinforced polymer (BFRP) composites were investigated experimentally in this thesis. The weight percentage of 0.1, 0.3, 0.5 and 0.7% GNP was added to the epoxy matrix (EP). Nanocomposites were produced in two stages using hand lay-up and vacuum infusion methods. Hardness and density measurements, tensile and wear tests of pure basalt fiber reinforced epoxy (Epoxy/BF) composite and GNP filled basalt fiber reinforced epoxy (GNP-Epoxy/BF) nanocomposites were carried out at room temperature (25 ± 3 °C) in accordance with ASTM standards. Tribological properties were investigated in the ball-on-disk wear tester under constant loads (10 N and 15 N) at a sliding speed of 0.75 ms-1 using chromium steel balls with high hardness (62 HRC) and wear resistance. BFRP composite materials were aged in salt water for 2, 4 and 6 months, in order to investigate the effects of corrosive environment. At the end of the two-month period, tensile and wear tests were repeated and the results were compared with the normal ambient test results. The effects of GNP contribution on thermal stability were determined by TGA analysis. The damage mechanisms of the composites subjected to tensile and wear tests, degradation of the composites aged in salt water, and the destructive effects of salt water on the matrix and fibers were examined by SEM images. Elementary sedimentation, chemical interactions or new bond formation in the structure, which may occur on the surfaces of composites, were interpreted by EDX, FT-IR analysis and AAS measurements. GNP additive strengthened fiber-matrix interface interaction in Epoxy/BF composites, resulting in significant increases in tensile strength, % elongation and modulus of elasticity. GNPs, known as solid lubricant, have been effective in reducing the coefficient of friction in contact areas. GNP-Epoxy/BF nanocomposites have lower wear and higher wear resistance compared to Epoxy/BF composites. During salt water aging, GNPs showed a barrier effect and reduced water intake into the matrix. EP matrix fibers, which showed less damage in nanocomposites with low water absorption, continued to protect and delayed damage to the fibers.