Abstract
An arc-sprayed amorphous Al–Ti–Ni coating on S355 structural steel was processed by laser remelting (LR) at powers of 600, 800, and 1000 W. The surface-cross-sectional morphologies, chemical element distributions, and phase compositions of the as-obtained Al–Ti–Ni coatings were analyzed using a scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), and X-ray diffractometer (XRD), respectively. The immersion corrosion tests of Al–Ti–Ni coatings in 3.5% NaCl solution for 720 h were performed to investigate the effects of LR power on their immersion corrosion behaviors. The test results show that the amorphous Al–Ti–Ni coatings form good metallurgical bonding with the substrate after LR. The AlNi, Al3Ti, Al3Ni2, Ti3O5, and Al2O3 amorphous phases are detected in the Al–Ti–Ni coatings after LR. The corrosion potentials of Al–Ti–Ni coatings after LR show a positive shift relative to that of S355 steel, implying that the corrosion resistance of Al–Ti–Ni coatings was superior to that of S355 steel. A dense protective Al2O3 film is formed on the Al–Ti–Ni coating surface at an LR power of 1000 W, at which power the highest corrosion potential of −0.233 V is observed. The corrosion mechanisms of Al–Ti–Ni coating at the LR power of 1000 W are uniform corrosion and pitting corrosion, while those of Al–Ti–Ni coatings at the LR powers of 600 and 800 W are localized corrosion and pitting corrosion. The corrosion resistance of Al–Ti–Ni coating with the LR power of 1000 W is better than those at the LR powers of 600 and 800 W, effectively improving the corrosion resistance of S355 steel.
Highlights
Offshore platforms are usually made of metallic materials, such as S355 low-alloy structural steel [1]; chloride ions present in the marine environment can be a cause of corrosion for offshore platforms in seawater [2,3]
In the absence of effective corrosion protection measures, the offshore platform will suffer from severe corrosion in a few years, and the corrosion loss will surpass the damage caused by other natural disasters
The high cooling rate of the rapid solidification process (105 –108 K/s) naturally achieved by laser remelting (LR) is advantageous for the formation of amorphous alloys [17,18,19], which when used as coatings improve the corrosion resistance of metallic material
Summary
Offshore platforms are usually made of metallic materials, such as S355 low-alloy structural steel [1]; chloride ions present in the marine environment can be a cause of corrosion for offshore platforms in seawater [2,3]. The high cooling rate of the rapid solidification process (105 –108 K/s) naturally achieved by LR is advantageous for the formation of amorphous alloys [17,18,19], which when used as coatings improve the corrosion resistance of metallic material. LR can eliminate pores, destroy the layered structure, and remelt the entire thickness of the arc-sprayed coating; this results in the formation of a metallurgical bonding between the Al coating and the substrate and provides an extremely low rate of dilution of the coating, which is, in turn, beneficial for improving the bonding strength and corrosion resistance of the coating [20,21,22]. Li et al [28] investigated the influence of remelting scanning speed on the amorphous forming ability of Ni-based alloy fabricated by laser cladding and et al [29] analyzed the microstructure and corrosion resistance of Fe-based. Theoretical basis for the application of amorphous Al–Ti–Ni coatings on offshore platforms
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
