Characterization of airborne wear debris produced by brake pads pressed against HVOF-coated discs

Menapace, C.; Mancini, Alessandro; Federici, Matteo; Straffelini, Giovanni; Gialanella, Stefano

doi:10.1007/s40544-019-0284-4

Cited by 33 publications

(22 citation statements)

References 29 publications

(34 reference statements)

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“…For improving the tribological properties of cast-iron discs, some researchers have proposed cryogenic treatments [69,70], conventional heat treatment processes, viz. quenching, tempering, and austempering [48,58,71], and coatings [18,72]. The cryogenic treatment, involving liquid nitrogen, affects not just the surface but the entire cross-section of the disc and improves its wear resistance.…”

Section: Cast Iron Discsmentioning

confidence: 99%

“…Moreover, the coated discs perform better than uncoated ones in terms of particle emissions, as demonstrated in a study, using pin-on-disc (PoD, see Section 3.1.2) testing [72]. Menapace et al [18] conducted a comparative investigation on the emissions from uncoated and WC-CoCr-coated cast iron discs against the same LM pads, using a dyno-bench test rig. From the characterization of the collected particles, in the 2.5 µm to 30 nm range, a consistent reduction in the emission, along with the concentration of iron oxide, was evidenced.…”

Section: Cast Iron Discsmentioning

confidence: 99%

“…EDXS too, cannot provide reliable concentrations of light elements [90,125], a limitation that can be overcome with alternative techniques, like the inductively coupled mass spectrometry (ICP-MS) [126]. Accurate information regarding the phase composition of the bulk materials can be obtained through X-ray diffraction (XRD), which becomes particularly valuable when data analysis is based on a full pattern fitting procedure based on the Rietveld method [127,128], as done in [18,48,129]. On the basis of phase composition, the bulk materials can be classified into the categories discussed in Section 2, and specific properties, for instance, abrasive character and the effect of present lubricants on it, can be gauged.…”

Section: Characterization Of Bulk Brake Materialsmentioning

confidence: 99%

See 2 more Smart Citations

Experimental Characterization Protocols for Wear Products from Disc Brake Materials

et al. 2020

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The increasing interest in the emission from the disc brake system poses new challenges for the characterization approaches used to investigate the particles emitted from the wearing out of the relevant tribological systems. This interest stems from different factors. In the first place, a thorough characterization of brake wear particles is important for a complete understanding of the active tribological mechanisms, under different testing and servicing conditions. This information is an important prerequisite not only for the general improvement of brake systems, but also to guide the development of new materials for discs and brake pads, responding better to the specific requirements, including not only performance, but also the emission behavior. In this review paper, the main material characterization protocols used for the analyses of the brake wear products, with particular regard for the airborne fraction, are presented. Reliable results require investigating the fine and ultrafine particles as concerns their composition together with their structural and microstructural aspects. For this reason, in general, multi-analytical protocols are very much recommended.

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Section: Cast Iron Discsmentioning

confidence: 99%

Section: Cast Iron Discsmentioning

confidence: 99%

Section: Characterization Of Bulk Brake Materialsmentioning

confidence: 99%

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Experimental Characterization Protocols for Wear Products from Disc Brake Materials

et al. 2020

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“…The results were quite promising, showing that this kind of coating can effectively contribute to the reduction of particulate matter emissions. Menapace et al [39] extended the study, investigating the chemical and phase composition of the airborne fraction of wear debris collected during dyno-bench tests with WC-CoCr coated discs. One of the main results of the investigation was the detection of some critical components transferred from the coating to the airborne fraction of wear debris, including WC and Co.…”

Section: Hvof Cermet Coatings For Brake Discsmentioning

confidence: 99%

HVOF Cermet Coatings to Improve Sliding Wear Resistance in Engineering Systems

Straffelini

Federici

2020

Coatings

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High-Velocity Oxy-Fuel (HVOF) cermet coatings are widely employed in sliding conditions, due to their optimized microstructure, composed of a carbide phase embedded into a ductile metal matrix. In the present short review, the characteristics and mechanical properties of HVOF cermet coatings are considered, and the dry sliding behaviour of the main types of coatings is analysed at room and high temperature. The role of microstructural parameters, including defects, surface roughness and the nature of the counterface is discussed. The review also considers a specific application, namely HVOF coatings for discs in brake applications. This application is gaining in importance, since it reduces the wear of the braking components and thus the emission of airborne particulate matter.

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“…The study of Wahlström et al [18] demonstrated that significant potential of HVOF cermet coatings in reducing the emission of airborne particles associated with the material wear of braking systems. Similarly, Menapace et al [19] extended the study to investigate the chemical and phase compositions of the airborne fractions of wear debris collected during dyno-bench tests using WC-CoCr-coated discs. One of the main results of the investigation was the detection of critical elements transferred from the coating to the airborne fraction of the wear debris, i.e., cobalt; this has raised additional concern.…”

Section: Introductionmentioning

confidence: 99%

Pin-on-disc study of dry sliding behavior of Co-free HVOF-coated disc tested against different friction materials

et al. 2021

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The dry sliding behavior of three commercial friction materials (codenamed FM1, FM2, and FM3) tested against a Co-free cermet coating produced by high-velocity oxy-fuel (HVOF) on gray cast-iron discs is investigated. FM1 is a conventional low-metallic friction material, FM2 is developed for using against HVOF-coated discs, and FM3 is a Cu-free friction material with a low content of abrasives and a relatively high concentration of steel fibers. For the tribological evaluation, they are tested on a pin-on-disc (PoD) test rig against Co-free HVOF-coated discs, with particular attention to the running-in stage, which is fundamental for the establishment of a friction layer between the two mating surfaces, i.e., the pin and disc. The PoD tests are performed at room temperature (RT) and a high temperature (HT) of 300 °C. At RT, all materials exhibit a long running-in stage. At HT, no running-in is observed in FM1 and FM2, whereas a shorter running-in period, with respect to the RT case, is observed in FM3 followed by the attainment of a comparatively high coefficient of friction. At RT, the pin wear is mild in all cases but severe at HT. FM3 shows the lowest wear rate at both temperatures. Moreover, the coated disc shows no wear when sliding against the FM3 friction material. All the results are interpreted considering the microstructural characteristics of the friction layers formed on the sliding surfaces. The findings of the present study provide insights into reducing wear in braking system components and hence reducing environmental particulate matter emissions from their wear, through the use of disc coatings.

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Characterization of airborne wear debris produced by brake pads pressed against HVOF-coated discs

Cited by 33 publications

References 29 publications

Experimental Characterization Protocols for Wear Products from Disc Brake Materials

Experimental Characterization Protocols for Wear Products from Disc Brake Materials

HVOF Cermet Coatings to Improve Sliding Wear Resistance in Engineering Systems

Pin-on-disc study of dry sliding behavior of Co-free HVOF-coated disc tested against different friction materials

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