Corrosion Communications (Jun 2024)

Oxidation resistance of Mo/Cr bilayer coating on Zr alloy in a 1200 °C steam environment

  • Zheng Wang,
  • Yingpeng Zhang,
  • Shenghao Zhou,
  • Zhenyu Wang,
  • Yirong Yao,
  • Aiying Wang,
  • Ming Li,
  • Peiling Ke

Journal volume & issue
Vol. 14
pp. 49 – 57

Abstract

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The Cr-coated Zr alloys demonstrate excellent resistance to high-temperature steam oxidation. However, the rapid diffusion pathways for oxygen formed by the inter-diffusion between the coating and alloy at high temperatures significantly affect the steam oxidation resistance of the coated alloys. To address this issue, we developed a Mo/Cr bilayer coating on Zr alloy by a combination of dc-MS and HiPIMS surface treatments. The coating exhibits outstanding steam oxidation resistance at high temperatures, resulting in a mass gain approximately 86.6% and 44.1% lower than that of the bare Zr alloy and Cr coating, respectively, after 30 min of steam oxidation at 1200 °C. This is mainly because, during the oxidation process, the Mo interface layer undergoes a transformation into a thin and high-quality double diffusion layer structure, effectively avoiding high-temperature inter-diffusion between the Cr coating and Zr alloy, thereby inhibiting the formation of oxygen diffusion pathways.

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