Friction and Tribocorrosion Behavior of Fe-Cr-B Alloys Fabricated via Extreme High-Speed Laser-Induction Hybrid Cladding

Abstract

Fe-Cr-B coatings were fabricated using laser-induction hybrid cladding and extreme high-speed laser-induction hybrid cladding (EHIC), and their microstructural evolution, dry friction performance, and tribocorrosion behavior were systematically investigated. The results indicate that the coatings consist of a matrix and eutectic region comprising M2B and martensite. With increasing scanning speed, the coarse dendritic matrix transforms into an equiaxed structure, and the overall microstructure becomes significantly refined. The dry friction mechanisms of the Fe-Cr-B coating involve oxidation and abrasive wear. The eutectic region constitutes the primary load-bearing and wear-resistant constituent within the coating. Increasing its fraction directly enhances the overall wear performance. Furthermore, the formation of a tribolayer during testing contributes to improved wear resistance. These combined factors lead to a reduction in the wear rate from 99.7 × 10−3 mm3·N−1·m−1 to 50.2 × 10−3 mm3·N−1·m−1 as the scanning speed increases. In corrosive media, the formation of a tribolayer is hindered, and electrochemical corrosion diminishes the resistance of the coating to plastic deformation, leading to a substantial increase in the wear rate. Under these conditions, the wear mechanism transitions to one dominated by abrasive wear. Owing to the high fraction of the eutectic region in the EHIC coating, its tribocorrosion performance is superior. As the scanning speed increases, the wear rate decreases from 255.8 × 10−3 mm3·N−1·m−1 to 175.4 × 10−3 mm3·N−1·m−1.