A1 Refereed original research article in a scientific journal
Enhancing Cold-Sprayed Nickel–Aluminum Bronze Coatings on Magnesium via Scanner-Based Laser Remelting
Authors: Vinay, Gidla; Kant, Ravi; Piiroinen, Aki; Nayak, Chinmayee; Ganvir, Ashish; Singh, Harpreet
Publisher: Springer Science and Business Media LLC
Publication year: 2026
Journal: Journal of Thermal Spray Technology
ISSN: 1059-9630
eISSN: 1544-1016
DOI: https://doi.org/10.1007/s11666-025-02150-w
Publication's open availability at the time of reporting: No Open Access
Publication channel's open availability : Partially Open Access publication channel
Web address : https://doi.org/10.1007/s11666-025-02150-w
Nickel–aluminum bronze (NAB) coatings are widely used in marine and industrial applications due to their excellent corrosion resistance, but their deposition on soft, low-melting substrates such as magnesium (Mg) remains challenging. This study investigates the cold spray deposition of as-received and heat-treated NAB (unsegregated) powders on Mg and NAB substrates, followed by post-processing using a fine-beam scanner-based laser remelting system. The as-deposited coatings improved the corrosion resistance of Mg substrates; however, they exhibited high porosity (5.2 ± 0.7%) and poor inter-splat bonding, as evidenced by the dislodgement of weakly bonded splats during polishing. Laser remelting with optimized parameters selectively fused layers to depths ranging from ~ 42 µm to ~ 220 µm. By remelting only the top surface layers (~63 µm), surface porosity, and inter-splat defects were sealed effectively, while the underlying cold-sprayed microstructure remained unaltered. Phase analysis confirmed martensitic transformation in the remelted layer, with no detectable oxidation due to effective argon shielding. Electrochemical testing revealed a 52% reduction in corrosion current density after remelting. This study demonstrates the feasibility of utilizing scanner-based laser remelting as a post-processing method, offering a controllable approach for selectively refining cold-sprayed coatings made of hard and brittle materials on soft substrates.
Funding information in the publication:
The authors would like to thank Dr. Ravi Mohan Prasad (IIT Ropar) for heat treatment facility and Materials Research Infrastructure (MARI) at Department of Physics and Astronomy, University of Turku for access and support with the XPS facilities. Gidla Vinay gratefully acknowledges Dr. Ermei Mäkilä (University of Turku) for assistance with SEM sample preparation. The coatings generated in this work were supported by the Department of Science and Technology (DST) through the project “Advanced Manufacturing Technology - Centre of Excellence (AMT-CoE) on Degradation Resistant Thermal Spray Coatings Engineered for Indigenous Industrial Applications (DST/TDT/AM/2022/143)” established at IIT Ropar. The cold spray system used for this study was established through MHRD-DST funded Uchhatar Avishkar Yojana (UAY, IITRPR_001). Prof. Ashish Ganvir acknowledges financial support from GREEN-BAT (Dnr 352517), co-funded by the Research Council of Finland and the European Union under the M-ERA.NET 2021 framework, as well as the SOLACE (Dnr 360540) Academy research fellowship, funded by the Research Council of Finland, for enabling testing and characterization support for this work.
