Novel dealloying structures and ageing behaviors of Cu-Zr metallic glass ribbons

Melt-spun Cu64.5Zr35.5 metallic glass ribbons were subject to 250 °C annealing for 0.5 to 2 h without leading to crystallization. Both the as-spun ribbon and the annealed ribbon were then reserved at room temperature and aged for one month, during which all samples became crystallized and oxidized on the surface. The surface of the aged ribbons tuned into brassy yellow and was featured an unchanged amorphous area and a nano-crystalline area fully decorated with crystallization and oxidation products. The two areas responded differently to the following dealloying process carried out in 0.025 M HF. The amorphous area were turned into nanoporous structure, but the dealloyed nano-crystalline area showed more complex morphology, which was composed of micron-sized Cu2O crystals rooted in the nanoporous structure.