Effect of a Cr2O3/A-Al2O3 Coating on the Corrosion Behavior of Incoloy 800H Alloy in High Temperature Impure Helium

Abstract In high temperature gas cooled reactor (HTGR), there is a small amount of helium in the primary coolant (ppm level) impure impurities, which will corrode the alloy materials of high temperature reactor and affect the performance of equipment in high temperature environment. The coating preparation technology on the alloy surface can effectively protect the alloy matrix, greatly reduce the corrosion rate of alloy, and improve the reliability and safety of equipment. In this paper, a Cr2O3/α-Al2O3 multilayer barrier coating prepared by RF magnetron sputtering was used to coat Incoloy 800H alloy, and the corrosion behavior of Incoloy 800H alloy with and without coating under selected high-temperature impure helium was investigated. After the experiment, the corrosion results were analyzed by weighing, scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS). The results showed that Cr2O3/ α-Al2O3 barrier coating partially fell off after high temperature corrosion; The internal oxidation phenomenon of the alloy was not obvious, and the coating can inhibit the oxidation and carburization of the alloy; The mass of the alloy increased after corrosion, and the mass gain of the coated alloy was lower than that of the uncoated alloy.