b'Advanced Coating and Surface Modification Technologiesfor SiC-SiC Composite for Hydrothermal Corrosion Protectionin Light Water ReactorPrincipal Investigator: Dr. Kumar Sridharan, University of Wisconsin-Madison Team Members/Collaborators: Dr. Hwasung Yeom, University of Wisconsin-Madison; Dr. Adrien Couet, University of Wisconsin-Madison; Dr. Peng Xu, Westinghouse Electric Company; Dr. Sergey Chemerisov, Argonne National LaboratoryChromium coatingS ilicon carbide (SiC)-SiCf compos- and coating-substrate interfacial ites are being investigated formicrostructures. The mechanical use as an accident tolerantbehavior of the coating materials deposited by PVDfuel (ATF) cladding material inhas been investigated using micro- greatly enhances thelight water reactors (LWR). SiCand nano-mechanical test methods. feasibility of the use ofoffers greater oxidation resistanceCorrosion performance and thermal SiC-SiCf composite asand high temperature strength instability of the coatings has been an accident tolerant fuelsevere accident conditions ( 1200investigated with a variety of cladding material in lightC steam) compared to the currentlyexperimental systems to assess the water reactors. used Zr-alloys. However, SiC experi- performance of coatings in a variety ences corrosion at normal reactorof simulated reactor environments.operating conditions (i.e., hydro-thermal corrosion) through theProject Description: reaction of SiO2 with water at ~300 C,A central objective of this project is leading to contamination of thethe development and optimization of coolant and dimensional changescoating technologies for the SiC-SiCf of the cladding. In this project,composites. In particular, coatings surface modification and coatingproduced using state-of-the-art PVD technologies are being developed totechnologies have been studied protect the SiC-SiCf cladding againstextensively. The microstructural hydrothermal corrosion. Cr hascharacterization, mechanical property been selected as the coating mate- analysis, and performance testing of rial on account of its outstandingthese advanced coatings is of great hydrothermal corrosion resistanceinterest to both the nuclear materials in pressurized water reactor waterand thin film scientific communities.conditions. The primary focus ofPure Cr coatings produced with PVD this work has been on physical vaporhave been investigated extensively deposition (PVD) of Cr coatings.in this project. The evaluation of Detailed characterization of theprocessing-structure-property rela-coatings has been performed totionships for the Cr coatings studied understand the effect of depositionin this project builds upon the body parameters on the resultant coatingof knowledge of PVD Cr coatings 72 2022|AFC ACCOMPLISHMENTS'