Dry tribological behaviour of polymer-based friction composites containing blast furnace slag: effect of slag content

Purpose This study aims to investigate the effect of blast furnace slag (BFS) content on the dry tribological behaviour and physical properties of polymer-based friction composites. The aim is to determine an optimum BFS content that provides balanced friction stability, acceptable wear behaviour and favourable thermal characteristics. Design/methodology/approach Composites containing 0, 5, 10 and 15 Wt.% BFS were fabricated using a dry mixing and hot pressing process. Tribological behaviour was evaluated under dry sliding conditions using a pin-on-disc test according to ASTM G99. Physical properties, thermal behaviour and worn surface morphology were analysed to relate the results to wear mechanisms. Findings BFS significantly influenced the tribological and thermal behaviour of the composites. The sample containing 5 Wt.% BFS showed the most stable friction coefficient and the lowest heat swell with well-developed contact plateaus. Although this composition exhibited slightly higher wear and interfacial temperature than some samples, it provided the most stable friction behaviour and the lowest heat swell under the tested conditions. Higher BFS contents increased interfacial temperature and reduced friction stability. Research limitations/implications Experiments were conducted under short-duration dry sliding conditions. Future studies should investigate wider operating conditions, including higher temperatures representative of real braking environments. Practical implications Approximately 5 Wt.% BFS can improve braking stability while maintaining stable tribological behaviour, suggesting potential use in environmentally friendly brake pad materials. Originality/value This study provides a systematic evaluation of low BFS contents in polymer-based friction composites and relates tribological behaviour to worn surface morphology. The results highlight BFS as a sustainable and low-cost alternative filler for friction materials.