Influence of Al concentration on mechanical property and oxidation behavior of Zr-Al-C coatings

Abstract

Accident tolerant fuels are proposed for light water reactors to improve the safety margin in the event of severe accidents, especially under a LOCA scenario. In this work, Zr-Al-C coatings were synthesized by magnetron sputtering, with different aluminum concentrations incorporating binary carbide ZrC0.55. Based on the combined results of XRD, TEM, and XPS, 7.6 at.% Al coating resulted in a solid solution phase, while a further increase in the Al concentration to 17.7 at.% and 26.3 at.% led to the formation of nanocomposites. The average grain size of the Zr-Al-C coatings was in the range of 8–11 nm, and the hardness was on the order of 15–30 GPa. Meanwhile, the 7.6 at.% and 17.7 at.% Al coatings showed enhanced oxidation resistance against air up to 1000 °C due to formation of continuous oxide scale consisting of t-ZrO2 and Al2O3. Thus, in terms of the mechanical property and high-temperature oxidation resistance, the Zr-Al-C coatings had much better performance than the ZrC0.55 coatings.