Sustainable Development and Characterization of CNT-Reinforced Composite Friction Materials for Advanced Vehicle Brake Systems

Hegab, Ahmed Mohamed; Abd El Tawwab, Ali; Mourad, M. A. H.; Moheyeldein, Mohamed

doi:10.21608/ejchem.2025.417908.12249

Sustainable Development and Characterization of CNT-Reinforced Composite Friction Materials for Advanced Vehicle Brake Systems

Articles in Press

Document Type : Original Article

Authors

¹ Automotive and Tractors Engineering Department, Faculty of Engineering, Minia University, El-Minia, 61111 Egypt.

² Automotive and Tractors Engineering Department, Faculty of Engineering, Minia University

10.21608/ejchem.2025.417908.12249

Abstract

This article investigates the effects of incorporating carbon nanotubes (CNTs) on the tribo-mechanical properties and structural characteristics of asbestos-free composite brake friction materials. The study compares a commercial brake pad (CBP) with three newly fabricated samples containing varying CNT concentrations 0.5 – 1.5 wt.%. The CNTs used were synthesized via an electric arc-discharge in liquid technique, yielding diameters of 7 nm and lengths of 90 nm. Characterization was performed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The results indicate that the inclusion of CNTs significantly improves the material's properties by enhancing microstructural homogeneity and reducing porosity, especially in the sample with 1.0% CNT. While the CBP has a heterogeneous microstructure with uneven particle distribution, the CNT-reinforced composites show a more uniform dispersion of elements, which is attributed to the CNTs bridging different phases. The mechanical and physical tests further demonstrate this improvement. The addition of CNTs resulted in a significant increase in hardness, from 48 HV in CBP to 75–76 HV in the CNT samples. Additionally, CNTs reduced oil and water absorption, as well as heat swell, compared to the CBP. The CNT2 sample, with a 1.0% CNT concentration, showed the highest compressive strength, exceeding 250 MPa, while the CBP's strength was around 160 MPa. Overall, the findings suggest that the use of CNTs as a reinforcing filler provides a promising approach for developing high-performance, sustainable, and eco-friendly brake pad materials with superior mechanical and tribological properties.

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