Microstructure, corrosion resistance and oxidation behavior of Cr-coatings on Zircaloy-4 prepared by vacuum arc plasma deposition

Cr-coated Zircaloy-4 samples are prepared by vacuum arc plasma deposition and their microstructure, corrosion resistance and oxidation behavior are investigated. The as-received coating is dense with no pores or defects observed. The corrosion rate of Cr coating is significantly lower than Zircaloy-4 under the condition simulating the coolant of both PWRs and BWRs. Cr coating can prevent zirconium from harsh and fatal oxidation in air. Bubbles are found on the surface of the coated samples after oxidizing at 1200 degrees C. These bubbles are within the Zr-substrate, locating at the interface of alpha Zr (O) layer and prior beta Zr.