High temperature Cr-Zr interaction of two types of Cr-coated Zr alloys in inert gas environment

The Cr-Zr interaction of two types of Cr coated Zr alloy accident tolerant fuel (ATF) claddings, deposited by cold spraying and magnetron sputtering, was studied in argon in the temperature range from 1100 to 1300°C. A tube furnace with a sample lock system was used for fast exchanging samples at test temperature. Inter-diffusion between the coating and the substrate results in the formation of an intermetallic ZrCr₂ layer and a solid solution layer beneath. Some pores were formed on the interlayer by a Kirkendall-type mechanism. The interlayer growth rate of cold sprayed samples was always slightly higher than that of magnetron sputtered samples in the same condition. Moreover, the temperature-dependent consumption coefficient of the Cr coating was calculated and fitted to an Arrhenius function. The dissolution and precipitation behavior of Cr in the Zr substrate and the diffusion behavior of Zr in Cr coating were also studied.