Preparation of phosphate conversion coating on laser surface textured surface to improve corrosion performance of magnesium alloy

In this work, we proposed a surface modification strategy to improve corrosion resistance of magnesium alloy by combining laser surface texturing (LST) with phosphate conversion coating (PCC). The surface and section morphologies, adhesive performance and electrochemical corrosion properties of the coated samples were investigated. Results demonstrate that the multimodal surface roughness and high specific area generated by LST facilitate the deposition of coating, increase the adhesion of coating and reduce the shedding rate of coating in the scratch test. Electrochemical analyses reveal that the coated sample with LST pretreatment shows superior corrosion properties, and fewer areas were damaged by corrosive medium compared with the coated sample without LST. Immersion test results reveal that LTC sample shows the best long-term corrosion resistance among all samples.The underlying mechanisms of the PCC with LST pretreatment to improve the anticorrosive performance of Mg alloys are proposed. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, a surface modification strategy combining LST with PCC was proposed to enhance the corrosion resistance of magnesium alloy. Results showed that this strategy improved the adhesion and corrosion properties of the coating, with the sample pretreated with LST demonstrating superior corrosion resistance. The LTC sample exhibited the best long-term corrosion resistance among all samples tested.