Characterisation and corrosion behaviour of WAP coating on 300M steel

ABSTRACT

In this work, a special water-based aluminium phosphate (WAP) coating containing primer and finishing layers was applied on 300M steel. The curing temperature of the primer layer was about 250°C and that of the finishing layer was 200°C. The aluminium phosphate binder in both primer and finishing layers was barely crystallised, and the most effective binding phases were Al and aluminium phosphate. WAP coating showed the formation of corrosion product after 1000 h of neutral salt spray test. The results of electrochemical tests showed that the corrosion potential of the WAP coating was significantly higher than that of the high-strength substrate, and the capacitance arc amplitude of the coating was larger than that the substrate. The protection efficiency of WAP coating for 300M steel was 69.1%.

KEYWORDS:

• WAP coating
• 300M steel
• corrosion behaviour
• protective mechanism

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This project was supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China andthis fund is provided by Jiangsu Province for discipline construction, Natural Science Foundation for Excellent Young Scientists of Jiangsu Province, China [grant number BK20180068]; China Postdoctoral Science Foundation funded project, China [grant number 2018M630555]; the Fundamental Research Funds for the Central Universities, China [grant number NS2018039]. This work was also supported by the Opening Project of Key Laboratory of Materials Preparation and Protection for Harsh Environment [grant number NJ2018009] and Laboratory of Advanced Structural Materials and Application Technology [grant number ASMA201701].