Microstructure and corrosion behavior of chromium-rich stainless steel coatings deposited by different laser cladding processes
Siyu Sun, Zhiwei Wu, Minghao Pang, Jiaqiang Chang, Yu Xuan, Huan Qi, Rui Yang, Yingna Wu
Abstract
To replace the hard chrome plating process, chromium-rich stainless steel coatings with the thickness of over 500 μm are deposited on 27SiMn substrates by the high efficiency (0.5 m2/h) processes of ultra-high speed laser cladding (UHS) and broad beam laser cladding (BLC). The solidification process and microstructure characteristics, affected by the UHS's high cooling rate and BLC's broad energy input, are analyzed respectively using optical microscope, SEM and TEM, followed by the investigation of corrosion behavior via the kinetic potential test in 3.5% NaCl solution. The intrinsic relationship between microstructure and corrosion behavior is discussed from the viewpoint of solidification and corrosion mechanisms.