Brass in brake linings: Key considerations for its replacement

Abstract

Following the ban of its use in brake linings, asbestos has been replaced by various materials based on industrial feedback and trial and error, but without any real understanding of how it affects contact during braking. As copper too will be prohibited in a few years' time, we set out to study the influence of one of its alloys, namely brass. A simplified brass-containing material was developed for this purpose. This material has an anisotropic microstructure and consequently exhibits anisotropic mechanical behavior and increased thermal diffusivity. It displays good tribological behavior at moderate and high temperatures. A surface analysis shows that the contact area is very effective at trapping third bodies and developing secondary plateaus, which provide good conditions for stabilizing friction to a high degree, even at high temperatures.

Synergic effect of metallic fillers as heat dissipaters in the tribological performance of a nonasbestos disk brake pad

“…The specific gravity of the brake pads increased with the increased content of brass and zinc. This is as expected and is in agreement with the results achieved by Christol et al 15 because of the density of metallic particles, which are heavier than the barites. The brass fiber creates the void content in the FC, leading to decrease in the hardness of the brake pads.…”

Braking performance of friction materials: a review of manufacturing process impact and future trends

“…The last principal step for compression-moulding process is carried out generally in an oven preheated at fixed temperature and duration. But there are few studies that mentioned a gradual increase in post-curing temperature according to two [79] or three sequences [92]. If a stable performance is required from the early stage of the brake pad service, a scorching step is needed after post -curing.…”

“…Due to the current environmental regulations, organic friction materials (usually thermos-resin matrix) are the most automotive brake pads available in the market. Consequently, wide-ranging research is focused on the method with which this type of friction material is manufactured: compression-moulding technique [37,79].…”

Caracterização microestrutural de discos metálicos de aço AISI 4140 após ensaios tribológicos do tipo pino-disco, usando pinos de alumí­nio 6082-T6, cobre C10200 e latão C36000.

“…A caracterização da superfície dos discos do par alumínio-aço mostra regiões com a presença de ferro e predominantemente alumínio associado ao oxigênio, sugerindo a presença de ilhas de óxido de alumínio e, em alguns casos, a aglomeração de debris de ferro do disco misturados com os debris do pino, (DMITRIEV et al, 2008;RODRIGUES et al, 2017). A predisposição do latão de formar platôs secundários já foi descrita por Baklouti (BAKLOUTI et al, 2017) Figura 48 -Ensaio pino disco com pinos de cobre puro e de cobre com adição de chumbo. (a) Ensaio com pino de cobre puro com diferentes cargas normais; (b) Ensaio com pino de cobre com 20% de chumbo com diferentes cargas normais; (c) Ensaio com pino de cobre com 40% de chumbo com diferentes cargas normais; (d) Comportamento das quatro ligas em função da carga normal aplicada no ensaio.…”