Corrosion of zirconium alloy before and after CrN coating deposition

In this work, the effect of various types of heat treatment, steam and air oxidation on the structure, phase composition, and corrosion properties of the zirconium alloy E110 with a CrN coating deposited by the reactive magnetron sputtering method was investigated. It was found that at a temperature of 800 ◦ C , the coating retains a dense and homogeneous structure with high adhesion, whereas at 1100 ◦ C , partial delamination and cracking of the layer are observed due to thermal stresses. X-ray diffraction analysis showed that the main phases are represented by α -Zr and CrN. After heat treatment, slight changes in diffraction peak intensity were observed, and weak reflections that may correspond to metallic chromium were detected. Oxidation experiments in an air atmosphere at 700 ◦ C showed that the CrN coating significantly reduces mass gain and oxidation rate compared to the uncoated alloy. Steam corrosion tests at 1100 ◦ C confirmed that the CrN coating effectively prevents oxygen diffusion, preserving the structure and integrity of the layer. According to the results of electrochemical tests in 3.5 wt.% NaCl, the corrosion current density decreased from 3.63 µA/cm 2 to 1.03 µA/cm 2 , and the corrosion rate decreased from 0.0053 mm/year to 0.0000185 mm/year . The obtained data indicate that optimal heat treatment at 800 ◦ C followed by steam oxidation ensures the formation of a durable, heat-resistant, and corrosion-resistant CrN coating that effectively protects the zirconium alloy E110 from aggressive environments.