Microstructural and nanomechanical studies of PVD Cr coatings on SiC for LWR fuel cladding applications

The microstructure and nanomechanical properties of pure Cr coatings deposited on SiC with various physical vapor deposition (PVD) methods have been investigated for the mitigation hydrothermal corrosion SiC-SiCf (SiC fiber-reinforced matrix) composite fuel cladding in light water reactors (LWR). (4–7 ?m thick) were unbiased substrates using six variants magnetron sputtering processes: (i) standard (S-DCMS), (ii) pulsed (P-DCMS), (iii) ion-assisted (I-DCMS), (iv) direct current (PI-DCMS), (v) high-power impulse (HiPIMS), (vi) bipolar HiPIMS (B-HiPIMS). Microstructural characterization nanoindentation testing used to evaluate effects technique coating properties. application positive reverse pulses sputter target induced coarsening columnar grain structure, while ion bombardment during promoted densification microstructure. Both are exemplified B-HiPIMS deposition, resulting a high-density compressive residual stress. Material pile-up around nano-indents plastic work analyzed understand deformation behavior coatings. results suggest process be among promising LWR application.