Effects of sample bias on wear resistance of magnetron sputtered chromium coated zirconium alloy

Netto, TR, Evans, AK, Goddard, DT, Cooper, JL and Kelly, P ORCID: https://orcid.org/0000-0003-1008-4941 (2025) Effects of sample bias on wear resistance of magnetron sputtered chromium coated zirconium alloy. Surface and Coatings Technology, 498. 131847. ISSN 0257-8972

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Abstract

Research on accident-tolerant fuels (ATFs) for Light Water Reactors (LWRs) has focused on improving the safety of zirconium alloy fuel rods since the Fukushima accident in 2011. Additionally, normal LWR operating conditions cause fretting wear on the fuel rod surface, which requires tribological improvements. Chromium-based coatings on zirconium alloys are one of the most advanced concepts for developing a fuel that can withstand accidents. Both under operating conditions and when subjected to high-temperature steam, Zr alloys with protective coatings demonstrated improvements, compared to uncoated surfaces. This study aims to evaluate the effect of substrate bias on the structure and tribological properties of chromium films deposited by magnetron sputtering onto Zr alloy nuclear fuel rod cladding. The coatings were also characterised by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and optical profilometry. The hardness of the coating was measured with a nano-indenter. Initial finding indicates that the application of a low substrate bias of −50 V enhances film density and adhesion and also reduces the coating wear rates, in comparison to higher biases (−100 V to −150 V) or no applied bias.