Coating Method Dependence of Tribological Behaviors in CrAl-coated Zr Cladding

Coated claddings with high temperature oxidation resistance alloys are considered as one of the strong candidates for accident-tolerant fuel (ATF) claddings [1-3]. Even though new materials such as FeCrAl, SiC/SiC composites showed outstanding corrosion resistance in simulated high temperature steam, there are many problems, such as neutron irradiation and dissolution in high temperature water, to be solved for commercial application. Up to now, Cr and Cr alloys can be applied as coating materials due to their outstanding oxidation resistance in high temperature steam. When coating materials are selected, coating method can be applied for the consideration of economy and safety issues. For example, arc ion plating or cold spray process can be applied to conventional Zr-based fuel claddings without microstructural changes during the coating process. However, interfacial bonding force can be weaken compared with direct energy deposition. Thus, coating methods can be optimized for obtaining applicable performance of coating layers. From previous test results, physical vapor decompositions can be selected as a process suitable for mass production. This is because coating materials can be stably deposited on conventional Zr-based claddings without coating damages such as pore, droplet, cracks, etc. However, coating layer has different oxidation resistance and mechanical properties under different coating methods even though the same coating materials are applied. In this study, the tribological properties of the Cr-5Al coating layers deposited by an Arc Ion Plating (AIP) and Sputtering (SP) method were experimentally evaluated.