Unveiling the pitting corrosion degradation response and the structural propagation of composite break block failure in different mediumDepartment of Mechanical Engineering, Bells University of Technology, Ota, Nigeria
E-mail: osfayomi@bellsuniversity.edu.ng Received: 11 November 2023 Accepted: 22 July 2024 Abstract: Failure in manufacturing, aerospace, marine, construction, and locomotive industries often stems from issues like fracture, corrosion, wear, distortion, and erosion. This research investigates the failure of railway composite brake block materials in different environments. Tests were conducted on used composite brake blocks in three media: 1.75% and 3.5% wt NaCl, 0.5 M and 1 M HCl and H2SO4. Corrosion analysis utilized linear polarization and open circuit techniques with a potentiostat/galvanostat. Microstructure, crystallography, and hardness were characterized using SEM/EDS, X-ray diffraction, and a digital superficial Brinell hardness tester. Results showed a hardness of 238.3 kgf/mm2 for the controlled sample, 236.8 kgf/mm2 for NaCl, and lower values of 233.4 kgf/mm2 and 233.6 kgf/mm2 for HCl and H2SO4, respectively. Corrosion rates were highest in acidic media, with 5.2390 mm/year for H2SO4 and 5.1342 mm/year for HCl, compared to 2.51662 mm/year in NaCl. SEM/EDS analysis revealed pronounced pitting in acidic media and uniform pits in chloride media. Phase formation indicated the presence of chloride halides and sulfide compounds like Fe(OCl) and C2(Fe, Na)CuCl. The primary components of the brake block were iron, silicon, aluminum, and carbon. Acidic environments accelerate failure due to weak bonding in the composite, while chloride systems demonstrate higher stability in rail applications. Keywords: Failure; Environment; Rail application; Corrosion; Brake; Characterization Full paper is available at www.springerlink.com. DOI: 10.1007/s11696-024-03617-w
Chemical Papers 78 (13) 7583–7594 (2024) |
Friday, September 27, 2024 
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