The evolution of tribological properties of graphite and glass fiber reinforced novolac matrix hybrid composites

Abstract Reinforcing the novolac matrix with glass fiber (GF) and graphite (Gr) was a promising method for producing high‐performance friction composites. In this context, the morphology of the matrix and additive particles used in the production of friction composites, microstructures, wear surfaces, and wear debris of friction composites were examined by scanning electron microscopy‐energy dispersive spectroscopy, while the crystal phases of the materials were scanned by X‐ray diffraction. Density measurements (Archimed's method), hardness, tensile behaviors, and thermal analyses (thermogravimetric analysis and differential scanning calorimetry) of friction composites were performed. The variations in coefficient of friction (COF) and temperature with the change in sliding time were observed in detail at different additive ratios. The tribological behaviors of these composites were tested using a computer supported block‐on ring machine at sliding speeds of 200, 250, 300, and 350 rpm, applied loads of 50, 100, 150, and 200 N and constant time of 1800 s under dry conditions. Results indicated that with increase in the GF and Gr content, the stability of the (COF) became more stable and effectively reduced the specific wear rate. In addition, the wear resistance increased in parallel with the increase in normal loads and sliding speeds for all conditions.