Tailoring vapor-deposited ZnMg-Zn bilayer coating for steels by diffusion-driven phase transformation

Soheil Sabooni, Emad Galinmoghaddam, A Turkin, Ewan Lu, R. J. Westerwaal, C Boelsma, Edzo Zoestbergen, Yutao T. Pei*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

This study reports a “high temperature fast annealing” approach to tailor the microstructure of ZnMg–Zn bilayer coatings through a diffusion-driven phase transformation and to improve the adhesion strength and corrosion resistance, simultaneously. Selection of the appropriate annealing condition, 250 °C for 3 min, promotes the formation of MgZn2 on the topmost surface of the coating and Mg2Zn11 at the interface of ZnMg/Zn. This results to an increase of the adhesion strength from 65 MPa in the as-deposited condition to 82 MPa after annealing as well as a reduction in the corrosion current density from 0.91 to 0.52 μA/cm2, indicating enhanced corrosion resistance. The diffusion of the elements at high temperatures is also modeled to predict the stability region of phases during the annealing treatment. An excellent correlation is obtained between simulation and the experimental results.
Original languageEnglish
Article number155448
JournalJournal of Alloys and Compounds
Volume836
Early online dateMay-2020
DOIs
Publication statusPublished - Sep-2020

Keywords

  • ZnMg-Zn bilayer Coatings
  • Adhesion
  • Diffusion-limited growth model
  • Phase transformation
  • Corrosion
  • physical vapor deposition (PVD)
  • ADHESION STRENGTH
  • CORROSION-RESISTANCE
  • MG COATINGS
  • MICROSTRUCTURE
  • BEHAVIOR
  • ZINC
  • INTERDIFFUSION

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