On the Gas-Phase Hydrogenation of E110 Zirconium Alloy with a Chromium Coating

This study examines the gas-phase hydrogenation of E110 zirconium alloy, both with and without chromium coatings of various morphologies and thicknesses in the range of 2.7–9.4 μm. Chromium coatings are deposited using two different configurations of magnetron-sputtering systems with cooled and “hot” chromium targets in an argon atmosphere. The samples are hydrogenated at a temperature of 360°C at a hydrogen pressure of 2 atm for 60 min. Based on the hydrogen absorption curves, optical emission spectroscopy, and X-ray diffraction analysis, the results demonstrate a significant decrease in hydrogen penetration into the zirconium alloy when the surface is coated with chromium. The hydrogen absorption rate can decrease from 2 × 10–3 to 4 × 10–4 cm3(H2)/(s cm2) when a chromium coating is applied to the surface of the E110 alloy. Hydrogen penetration through the chromium coating occurs via the diffusion mechanism with the accumulation of absorbed hydrogen observed at the coating–alloy interface. Adhesion testing of the Cr-coated alloy using an adhesion meter reveals that both types of coatings exhibit high adhesion strength against delamination and peeling (over 30 N) both before and after hydrogenation. The primary mechanism for the loss of coating integrity involves the formation of cracks in the Cr coatings. The critical load required to initiate cracking increases after sample hydrogenation.