Corrosion Science and Technology

The Corrosion Science Society of Korea (한국부식방식학회)
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Modifying the τ5c-Al20Fe5Si2(+Zn) Intermetallic Phase by Adding Vanadium into 55%Al-Zn Coating Alloy

  • Received : 2024.05.31
  • Accepted : 2024.08.07
  • Published : 2024.10.31
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Abstract

The presence of transition metals V, Cr or Mn in a 55%Al-Zn based coating metal can modify the equilibrium intermetallic phase, τ5c, by diffusion of transition metals and substituting for iron in the τ5c phase. We experimentally confirmed the modification of the IMC phase using various analytical techniques to characterize IMC phases. Experimental results confirmed the formation of a modified τ5c-Al20(Fe,V)5Si2(+Zn) intermetallic phase. The modified IMC phase showed periodic repeating layers with varying concentrations of V while still maintaining a constant (Fe+V)/Fe ratio within the homogeneity range of Fe in the equilibrium IMC phase. We proposed a reaction-diffusion mechanism for forming a modified IMC phase and a periodic layered structure. The initial reaction of the steel strip resulted in the formation of Fe4Al13 IMC phase. Al, Si, and Zn diffused and reacted with Fe4Al13 to form the equilibrium bcc phase, τ5c. The Fe4Al13 phase was consumed in the reaction, followed by diffusion of V into the newly formed phase by substitution of Fe by V, resulting in formation of the modified IMC phase. At 600 ℃, the τ5c phase could dissolve up to 4.13 wt% (2.73 at.%) V without changing its overall bcc crystal structure.

Keywords

Acknowledgement

We would like to thank our colleagues at BlueScope Innovating Labs for their engaging discussions during the course this work. We would also like to thank BlueScope Steel for permission to publish this work.

References

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