Performance Evaluation of Composite Friction Materials: Influence of Nature and Particle Size of Graphite

Abstract

This article deals with the role of graphite in friction materials on fade and recovery (F & R) properties especially in the context of its origin and particle size. Two series of composites with identical composition differing only in the type of graphite were developed and evaluated for their performance. These two series of composites, designated as S_N and S_S, were based on natural and synthetic graphites (of the same crystallinity ~75%), respectively and contained graphites which differed in particle size (460, 130, and 20 μm in S_N and 460, 160, and 35 μm in S_S). These friction composites were evaluated for their F & R performance following ECE R-90 regulation. The μ-performance, μ-fade, and μ-recovery were significantly influenced by the nature and particle size of graphites. It was observed that natural graphite was more effective to boost the μ-performance than the synthetic graphite. The fade property remained appreciably unaffected by the particle size in the series S_N whereas in S_S the fade resistance tended to increase with the decrease in particle size. The disc temperature rise in S_S was observed to be larger than that in S_N. Worn surface analysis by SEM proved to be useful in understanding the wear mechanisms.

Keywords

graphite friction materials fade and recovery.

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