“…The activated (alkaline bath treated or cycled) AB2 alloy surface consists of a top nonelectrochemical reactive ZrO2 patch, a surface oxide (~200 nm) with embedded metallic Ni/Coclusters [10,93], and an amorphous buffer layer (~100 nm) underneath [94]. In one example, the Zr/Ti ratios are 8.2, 1.2, 0.8, and 1.9 for the top oxide, supporting oxide, buffer oxide, and bulk, respectively, which indicates a higher leaching rate for Zr compared to that of Ti [94].…”