A Mechanistic Study on the Anti-Corrosive Performance of Zinc-Rich Polyester/TGIC Powder Coatings

Marshall Shuai Yang, Jinbao Huang, James Joseph Noël, Jian Chen, Ivan Barker, Jeffrey Daniel Henderson, Hui Zhang, Haiping Zhang, Jesse Zhu

Research output: Journal PublicationArticlepeer-review

8 Citations (Scopus)

Abstract

Powder coatings represent an environmentally friendly VOC-free alternative to widely used solvent-borne zinc-rich coatings, with economic and ecological benefits. In particular, powder coatings have several advantageous properties, such as chemical resistance and mechanical strength. However, the performance and characteristics of polyester-based zinc-containing powder coatings remain unknown. In this study, the corrosion performance of polyester powder coatings containing up to 80% zinc is compared. Electrochemical and salt-spray testing results indicate that coatings formulated with 80% zinc demonstrate superior anti-corrosive properties than coatings with lower zinc dosages. Two distinct behavioral phases of the coating with 80% zinc were observed by measurements of open circuit potential (OCP) and polarization resistance (Rp) during immersion tests—a phase indicative of a barrier effect and a phase consistent with galvanic protection. The evolution of the coating was further characterized and interpreted as five stages by electrochemical impedance spectroscopy (EIS), and the mechanistic details were discussed. This UV-resistant single-layer powder coating has the potential to replace the commonly used high-VOC multi-layer liquid coating systems at a significantly lower cost.

Original languageEnglish
Article number1853
JournalProcesses
Volume10
Issue number9
DOIs
Publication statusPublished - Sept 2022
Externally publishedYes

Keywords

  • EIS
  • anti-corrosive
  • barrier
  • electrochemical impedance spectroscopy
  • galvanic
  • pigment
  • polyester
  • powder coatings
  • sacrificial anode
  • zinc-rich

ASJC Scopus subject areas

  • Bioengineering
  • Chemical Engineering (miscellaneous)
  • Process Chemistry and Technology

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