Polymeric composites represent an advantageous choice for brake pads materials, offering a good balance between costs and performances. In this work, composite brake pads based on barite, potassium titanate and aramid fibers embedded in a polymeric matrix of phenol formaldehyde resin have been wear-tested in laboratory against a class FC-250 cast iron using a car brake simulator and then characterize using different microscopic and spectroscopic techniques. Four main wear mechanisms were observed depending on brake pad composition, as follows: tribolayer formation, ceramic crystal pull-out, cleavage of the C-N bond in aramid pulp fibres, and dissolution of barite to produce either ammonium or potassium sulphate. In the presence of potassium titanate, both wear rate and tribolayer area coverage were clearly reduced. Spectroscopic techniques enabled us to resolve the physicochemical degradation mechanisms behind brake performance, suggesting their potential use as in situ probes.
Diagnostic spectroscopic tools for worn brake pad materials: A case study
Rondinella, A;
2019-01-01
Abstract
Polymeric composites represent an advantageous choice for brake pads materials, offering a good balance between costs and performances. In this work, composite brake pads based on barite, potassium titanate and aramid fibers embedded in a polymeric matrix of phenol formaldehyde resin have been wear-tested in laboratory against a class FC-250 cast iron using a car brake simulator and then characterize using different microscopic and spectroscopic techniques. Four main wear mechanisms were observed depending on brake pad composition, as follows: tribolayer formation, ceramic crystal pull-out, cleavage of the C-N bond in aramid pulp fibres, and dissolution of barite to produce either ammonium or potassium sulphate. In the presence of potassium titanate, both wear rate and tribolayer area coverage were clearly reduced. Spectroscopic techniques enabled us to resolve the physicochemical degradation mechanisms behind brake performance, suggesting their potential use as in situ probes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
