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Graphite, a solid lubricant having good thermal conductivity (TC) and lubricity is used as a friction modifier in friction material (FM) formulations. Since graphite can be from different origins (synthetic, natural, treated etc.) and particles can be of various sizes, shapes and varying in crystallinity and purity, a careful selection is required for achieving desired performance properties of the FMs. Thermo-graphite (TG), as claimed to be more thermally conducting along with number of beneficial properties by the manufacturer was used to develop multi-ingredient FM. Two FMs differing in only type of graphite (TG and natural graphite-NG) were developed and evaluated for various performance properties. Tribo-performance evaluation of both the FMs on inertia dynamometer (schedule JASO C406) led to the conclusion that TG based FM proved superior to NG based one in almost all the properties barring recovery performance. [ABSTRACT FROM AUTHOR]

Aramid fiber/pulp (AF*) is one of the most important ingredients, of non-asbestos organic (NAO) friction materials (FMs). In spite of its relatively high cost, it is invariably added to good quality FMs (~3 wt%) because it improves their wear resistance and processability. The present research was prompted by the need to optimize the amount of the pulp required to achieve the best performance. Six FMs were prepared. They contained aramid fiber/pulp additions from 0 to 10 wt% and were characterized for their physical, mechanical, chemical and tribological performance. Composites were evaluated on a full-scale brake inertia dynamometer following the procedure in a Japanese automobile testing standard (JASO C406). The 10 wt% aramid FM showed best overall performance while the composite without fibers was worst. Worn surfaces were characterized using scanning electron microscopy and energy-dispersive X-ray analysis. [ABSTRACT FROM AUTHOR]

Historically, copper (Cu) and its alloys have played a vital role as additives to non-asbestos friction materials (FMs). Their main functions include; to increase thermal conductivity, to act as a solid lubricant at high temperature, and to influence general tribological performance. Environmental concerns in most of the advanced countries have resulted in legislation to gradually phase out the use of Cu in FMs. Thus, the FM Industry is facing a challenge to replace Cu and its alloys in FMs with additives that will match the desired performance. The goal of this work was to test the potential of two new FM fillers (conductive rock-fibers and thermo-graphite-TG) on a brake dynamometer using standard test schedule (JASO 406). Five brake-pad materials, comprising two series, were developed with identical parent compositions. The first series called Copper Based (CB) consisted of two FMs with and without untreated Rockwool (RB) and natural graphite (NG). The second series designated as Copper-Free (CF) series contained three FMs with increasing wt% of rock fibers (10%, 15% and 20%), along with 10% TG. Physical and mechanical properties of the compression-molded pads were measured. Cu-based FM performed better than the Cu-free FMs, but not significantly in most of the important properties. For certain other properties, Cu-free FMs performed better. [ABSTRACT FROM AUTHOR]