Characterization of ultrafine particles from hardfacing coated brake rotors  

作　　者：Yezhe LYU Ankur SINHA Ulf OLOFSSON Stefano GIALANELLA Jens WAHLSTRÖM 

机构地区：[1]Department of Mechanical Engineering Sciences,Lund University,Lund SE-22100,Sweden [2]Department of Machine Design,KTH Royal Institute of Technology,Stockholm SE-10044,Sweden [3]Department of Industrial Engineering,University of Trento,Trento 38123,Italy

出　　处：《Friction》2023年第1期125-140,共16页摩擦（英文版）

基　　金：The authors are grateful for the financial support from FORMAS:Swedish Research Council for Sustainable Development(No.2020-02302)(Nescup project);The research also received funding from European Union's Horizon 2020 research and innovation programme(No.954377)(nPETS project).

摘　　要：Automotive brake rotors are commonly made from gray cast iron(GCI).During usage,brake rotors are gradually worn off and periodically replaced.Currently,replaced brake rotors are mostly remelted to produce brand-new cast iron products,resulting in a relatively high energy consumption and carbon footprint into the environment.In addition,automotive brakes emit airborne particles.Some of the emitted particles are categorized as ultrafine,which are sized below 100 nm,leading to a series of health and environmental impacts.In this study,two surface treatment techniques are applied,ie.,high-velocity oxygen fuel(HVOF)and laser cladding(LC),to overlay wear-resistant coatings on conventional GCI brake rotors in order to refurbish the replaced GCI brake rotor and to avoid the remelting procedure.The two coating materials are evaluated in terms of their coefficient of friction(CoF),wear,and ultrafine particle emissions,by comparing them with a typical GCI brake rotor.The results show that the CoF of the HVOF disc is higher than those of the GCI and LC discs.Meanwhile,HVOF disc has the lowest wear rate but results in the highest wear rate on the mating brake pad material.The LC disc yields a similar wear rate as the GCI disc.The ultrafine particles from the GCI and LC discs appeared primarily in round,chunky,and flake shapes.The HVOF disc emits unique needle-shaped particles.In the ultrafine particle range,the GCI and HVOF discs generate particles that are primarily below 100 nm in the running-in period and 200 nm in the steady state.Meanwhile,the LC disc emitted particles that are primarily~200 nm in the entire test run.

关 键 词：ultrafine particle high-velocity oxygen fuel laser cladding BRAKE particle size distribution particle morphology 

分 类 号：U463.5[机械工程—车辆工程]