b'also developed in collaborationWisconsin Ion Beam Laboratory to with industrial partners to depositstudy defect evolution in the coatings Cr coatings. The B-HiPIMS processand any mixing effects at the Cr-SiC resulted a fully dense coating underinterface, under irradiation.compressive residual stress due toScanning transmission electron the high atomic mobility and ionmicroscopy-energy dispersive spec-bombardment effects generatedtroscopy (STEM-EDS) and HRTEM during deposition. characterization of the Cr/SiC The B-HiPIMS Cr coating interface were performed at Idaho demonstrated excellent corrosionNational Laboratory (INL) by the performance in hydrothermalUniversity of Wisconsin graduate corrosion tests with oxidationstudent to analyze the extent of characteristics similar to that ofatomic mixing at the interface bulk Cr. Nanoindentation testing ofproduced by different deposition the coating materials showed thatprocesses. Results showed there may coatings which contain fine grainsbe an intermixed region 5-10 nm in separated by porosity tend to crackwidth, but further characterization during deformation due to weakis necessary. The strength of the Cr/intercolumnar adhesion. In compar- SiC interface will be measured at ison, the larger, densely packedINL using in situ microcantilever grains comprising the B-HiPIMSbending at room temperature and coating are more amenable to plastic300 C. In situ high temperature deformation and produce a morex-ray diffraction measurements ductile mechanical response. were also conducted at INL and In collaboration with Argonneshowed that at 300 C, the stressNational Laboratory (ANL), a uniquein the B-HiPIMS coating becomes corrosion system was designed andmore compressive than at room fabricated. Designed for use at thetemperature due to differential Low Energy Accelerator Facility atthermal expansion effects.ANL, the sample capsule is irradiated by 3 MeV electron to generate corro-sive water radiolysis products that may be present during reactor opera-tion. In addition, select coatings have been irradiated with heavy ions at ANL and the University of 2022|AFC ACCOMPLISHMENTS 77'