Influence of coating parameters on oxidation behavior of Cr-coated zirconium alloy for accident tolerant fuel claddings

The Cr coatings (4.5-9.0 mu m-thick) with porous/columnar and dense/columnar microstructure were deposited on Zr alloy. Oxidation was performed at 900, 1050, 1200 and 1400 degrees C in steam to define the role of coating microstructure and thickness on oxidation behavior of Cr-coated Zr alloy. The activation energy for chromium oxidation decreases from 249 to 124 kJ/mol when the coating microstructure changes from dense to porous. Both coatings types are consumed by Cr-Zr interdiffusion resulting in the similar thickness of residual Cr. The CrZr interdiffusion can prevent forming the Cr oxide film and cause direct oxidation of the alloy at 1400 degrees C.

Automated summary

In this study, Cr coatings with different structures and thicknesses were deposited on Zr alloy to investigate their oxidation behavior at different temperatures. It was found that the microstructure and thickness of the coatings significantly influenced the oxidation behavior of Cr-coated Zr alloy. The activation energy for chromium oxidation decreased significantly when the microstructure of the coating changed from dense to porous. In addition, the interdiffusion between Cr and Zr prevented the formation of chromium oxide film and caused direct oxidation of the alloy at high temperatures.