Functionalization of alumina particles to improve the performance of eco-friendly brake-pads


Abrasives, such as oxides of alumina (Al), silica (Si), zirconia (Zr), chromium (Cr) etc., are added to raise the friction level and also to remove the glaze on the disc so that surface will be rejuvenated continuously during braking and will contribute to maintain the desired friction level. However, these inorganic particles have less adhesion with the resin/binder and hence are easily dug out during wearing process contributing to higher wear. If efforts are made to enhance the filler-matrix adhesion, not only the wear of friction material (FM) should reduce, the particles may stay for a longer time on the tribo-surface of the pads to contribute fully towards controlling the coefficient of friction (μ). In the present study, alumina particles were selected for siloxane treatment to improve the filler-matrix adhesion. Two types of eco-friendly (free from asbestos and Cu) brake-pads were developed using alumina as a theme ingredient (treated and untreated) keeping all the parent formulation identical. An additional type of brake-pads without alumina particles was also developed to observe the effect of abrasive particles on the tribo-performance. The performance properties (physical, mechanical, and tribological) of brake-pads were compared when evaluated in identical conditions. The tribo-testing was done on full-scale brake inertia dynamometer following the procedure in Japanese automobile standard (JASO C 406). It was observed that siloxane treatment affected both friction and wear of brake-pads in a beneficial way. Wear resistance got increased 35% for siloxane treated pads. Worn surfaces were analysed using scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX) technique.


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Correspondence to Jayashree Bijwe.

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Vanvirsinh CHAUHAN. He received his master degree (M.E.) in mechanical engineering in 2008 from Gujarat University, Gujarat, India. He joined the State Government Engineering College as an assistant professor at Gujarat Technological University from 2011. Currently, he is pursuing Ph.D. from Indian Institute of Technology (IIT), Delhi, India. His research interests include friction materials, tribology, and noise-vibration.

Jayashree BIJWE. She did her Ph.D. from Indian Institute of Technology, Delhi (IITD), India, and is working as a professor in IITD since last 25 years. Her research areas cover tribology of polymer composites (dry bearings and materials, NAO Brake-pads and friction materials, and adhesives) and additives for oils and greases.

Ashish DARPE. He is a post-graduate in machine design from Visvesvaraya National Institute of Technology, Nagpur, India. He did his doctoral research at the Indian Institute of Technology Delhi in the area of rotor dynamics. He is currently a professor in the Department of Mechanical Engineering, IIT Delhi. His research interests include NVH, rotor dynamics, condition monitoring, and vibration and noise control.

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Chauhan, V., Bijwe, J. & Darpe, A. Functionalization of alumina particles to improve the performance of eco-friendly brake-pads. Friction 9, 1213–1226 (2021).

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  • friction materials
  • brake-pads
  • siloxane treatment
  • friction modifiers
  • inertia brake-dynamometer