Fiber texture-dependent oxidation behaviour of Cr-coated zirconium alloy in high temperature steam

Cr-coatings with distinct crystallographic fiber textures were deposited on zirconium nuclear fuel cladding material. The <100> textured Cr-coating demonstrated superior properties to the <110> and <111> textured ones after high temperature steam oxidation. Electron microscopy characterization revealed that improvement in oxidation resistance could be attributed to rapid growth of <100> Cr-coating grains which leads to reduced grain boundaries for oxygen diffusion and zirconia particle nucleation as well as the absence of transgranular nano-porosity arrays in the residual Cr-coating. This work demonstrates a novel mechanism of orientation-dependent Cr-coating corrosion, which is expected to guide optimized design of Cr-coated nuclear fuel cladding.