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A significant fraction of the non-exhaust particulate matter emissions from vehicular traffic comprises fine particles from the wear debris of brake pads and discs. Recent studies have shown that these emissions can be consistently reduced by using wear resistant disc coatings. This study thoroughly analyses the debris produced by a low-met brake pad, which is dyno-bench tested against both cast iron and WC-CoCr-coated brake discs. To achieve this, particles in the size range of 2.5 μm to 30 nm were collected and characterized. The results showed a consistent reduction in the particle emission as well as in the concentration of iron oxides, which are mainly released from the disc tribo-oxidation in the coated disc. Furthermore, a few tungsten carbides, released from the coating, were also observed in the wear fragments. The results of this study can be useful for improving the protective coating and consequently help in reducing particulate matter emission further.


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

Show Author's information C. MENAPACE1( )A. MANCINI2M. FEDERICI1G. STRAFFELINI1S. GIALANELLA1
Department of Industrial Engineering, University of Trento, Trento 38123, Italy
Brembo S.p.A., Bergamo 24040, Italy

Abstract

A significant fraction of the non-exhaust particulate matter emissions from vehicular traffic comprises fine particles from the wear debris of brake pads and discs. Recent studies have shown that these emissions can be consistently reduced by using wear resistant disc coatings. This study thoroughly analyses the debris produced by a low-met brake pad, which is dyno-bench tested against both cast iron and WC-CoCr-coated brake discs. To achieve this, particles in the size range of 2.5 μm to 30 nm were collected and characterized. The results showed a consistent reduction in the particle emission as well as in the concentration of iron oxides, which are mainly released from the disc tribo-oxidation in the coated disc. Furthermore, a few tungsten carbides, released from the coating, were also observed in the wear fragments. The results of this study can be useful for improving the protective coating and consequently help in reducing particulate matter emission further.

Keywords: wear debris characterization, wear disc, WC-Co coating, High velocity oxygen fuel (HVOF)

References(30)

[1]
T Grigoratos, G Martini. Brake wear particle emissions: A review. Environ Sci Pollut Res 22(4): 2491-2504 (2015)
[2]
R M Harrison, A M Jones, J Gietl, J X Yin, D C Green. Estimation of the contributions of brake dust, tire wear, and resuspension to nonexhaust traffic particles derived from atmospheric measurements. Environ Sci Technol 46(12): 6523-6529 (2012)
[3]
G Straffelini, R Ciudin, A Ciotti, S Gialanella. Present knowledge and perspectives on the role of copper in brake materials and related environmental issues: A critical assessment. Environ Pollut 207: 211-219 (2015)
[4]
T Policandriotes, P Filip. Effects of selected nanoadditives on the friction and wear performance of carbon-carbon aircraft brake composites. Wear 271(9-10): 2280-2289 (2011)
[5]
P C Verma, L Menapace, A Bonfanti, R Ciudin, S Gialanella, G Straffelini. Braking pad-disc system: Wear mechanisms and formation of wear fragments. Wear 322-323: 251-258 (2015)
[6]
P C Verma, M Alemani, S Gialanella, L Lutterotti, U Olofsson, G Straffelini. Wear debris from brake system materials: A multi-analytical characterization approach. Tribol Int 94: 249-259 (2016)
[7]
R Hinrichs, M A Z Vasconcellos, W Österle, C Prietzel. A TEM Snapshot of magnetite formation in brakes: The role of the disc’s cast iron graphite lamellae in third body formation. Wear 270(5-6): 365-370 (2011)
[8]
W Österle, I Dörfel, C Prietzel, H Rooch, A L Cristol-Bulthé, G Degallaix, Y Desplanques. A comprehensive microscopic study of third body formation at the interface between a brake pad and brake disc during the final stage of a pin-on-disc test. Wear 267(5-8): 781-788 (2009)
[9]
J Wahlström, L Olander, U Olofsson. Size, shape, and elemental composition of airborne wear particles from disc brake materials. Tribol Lett 38(1): 15-24 (2010)
[10]
T Grabiec. Wear and friction behavior of friction pairs tested with different types of grey cast iron and low met friction material. SAE Int J Passeng Cars-Mech Syst 7(4): 1361-1368 (2014)
[11]
J Wahlström, Y Lyu, V Matjeka, A Söderberg. A pin-on- disc tribometer study of disc brake contact pairs with respect to wear and airborne particle emissions. Wear 384-385: 124-130 (2017)
[12]
G Straffelini, P C Verma, I Metinoz, R Ciudin, G Perricone, S Gialanella. Wear behavior of a low metallic friction material dry sliding against a cast iron disc: Role of the heat-treatment of the disc. Wear 348-349: 10-16 (2016)
[13]
M Federici, C Menapace, A Moscatelli, S Gialanella, G Straffelini. Pin-on-disc study of a friction material dry sliding against HVOF coated discs at room temperature and 300 °C. Tribol Int 115: 89-99 (2017)
[14]
M Mosleh, P J Blau, D Dumitrescu. Characteristics and morphology of wear particles from laboratory testing of disk brake materials. Wear 256(11-12): 1128-1134 (2004)
[15]
J Kukutschová, P Moravec, V Tomášek, V Matějka, J Smolík, J Schwarz, J Seidlerová, K Šafářová, P Filip. On airborne nano/micro-sized wear particles released from low-metallic automotive brakes. Environ Pollut 159(4): 998-1006 (2011)
[16]
J K Gietl, R Lawrence, A J Thorpe, R M Harrison. Identification of brake wear particles and derivation of a quantitative tracer for brake dust at a major road. Atmos Environ 44(2): 141-146 (2010)
[17]
J Wahlström, A Söderberg, L Olander, A Jansson, U Olofsson. A pin-on-disc simulation of airborne wear particles from disc brakes. Wear 268(5-6): 763-769 (2010)
[18]
L Lutterotti, S Matthies, H R Wenk, A S Schultz, J W Jr Richardson. Combined texture and structure analysis of deformed limestone from time-of-flight neutron diffraction spectra. J Appl Phys 81(2): 594 (1997)
[19]
H M Rietveld. A profile refinement method for nuclear and magnetic structures. J Appl Cryst 2(2): 65-71 (1969)
[20]
J H Yuan, Q Zhan, J Huang, S Y Ding, H Li. Decarburization mechanisms of WC-Co during thermal spraying: Insights from controlled carbon loss and microstructure characterization. Mater Chem Phys 142(1): 165-171 (2013)
[21]
C Verdon, A Karimi, J L Martin. A study of high velocity oxy- fuel thermally sprayed tungsten carbide based coatings. Part 1: Microstructures. Mater Sci Eng A 246(1-2): 11-24 (1998)
[22]
G Perricone, V Matějka, M Alemani, G Valota, A Bonfanti, A Ciotti, U Olofsson, A Söderberg, J Wahlström, O Nosko, et al. A concept for reducing PM10 emissions for car brakes by 50%. Wear 396-397: 135-145 (2018)
[23]
G Perricone, M Alemani, I Metinöz, V Matějka, J Wahlström, U Olofsson. Towards the ranking of airborne particle emissions from car brakes - a system approach. Proc Inst Mech Eng, Part D: J Automob Eng 231(6): 781-797 (2017)
[24]
J L Lábár. Consistent indexing of a (set of) SAED pattern(s) with the Process Diffraction program. Ultramicroscopy 103(3): 237-249 (2005)
[25]
S Gialanella, G Ischia, L Maines, G Straffelini. A sample preparation protocol for electron microscopy investigations of filter collected ultrafine environmental particles, to be submitted to Ultramicroscopy (2019)
[26]
J Kukutschová, V Roubíček, K Malachová, Z Pavlíčková, R Holuša, J Kubačková, V Mička, D MacCrimmon, P Filip. Wear mechanism in automotive brake materials, wear debris and its potential environmental impact. Wear 267(5-8): 807-817 (2009)
[27]
E M Hotze, T Phenrat, G V Lowry. Nanoparticle aggregation: Challenges to understanding transport and reactivity in the environment. J Environ Qual 39(6): 1909-1924 (2010)
[28]
I Konyashin, A A Zaitsev, D Sidorenko, E A Levashov, B Ries, S N Konischev, M Sorokin, A A Mazilkin, M Herrmann, A Kaiser. Wettability of tungsten carbide by liquid binders in WC-Co cemented carbides: Is it complete for all carbon contents? Int J Ref Metals Hard Mat 62: 134-148 (2017)
[29]
P Kumar, L Pirjola, M Ketzel, R M Harrison. Nanoparticle emissions from 11 non-vehicle exhaust sources - a review. Atmos Environ 67: 252-277 (2013)
[30]
W Österle, C Prietzel, H Kloß, A I Dmitriev. On the role of copper in brake friction materials. Tribol Int 43: 2317-2326 (2010)
Publication history
Copyright
Acknowledgements
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Publication history

Received: 27 October 2018
Revised: 15 December 2018
Accepted: 22 February 2019
Published: 06 April 2019
Issue date: April 2020

Copyright

© The author(s) 2019

Acknowledgements

The authors would like to thank their colleague Gloria Ischia, Ph.D, for her valuable technical assistance for the TEM sample preparation and observations. Our colleague, friend, and project leader, Guido Perricone (Brembo S.p.A.) is also acknowledged for his continuous encouragement in pursuing our goals while working together within the H2020 EU Project: LOWBRASYS - a LOW environmental impact BRAke SYStem-GA: 636592. The EU Commission is acknowledged for its financial support.

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