Corrosive behavior of multi-phased quasicrystal alloys

Six quasicrystal alloys were created by varying their composition and subsequent microstructure. The corrosion of those quasicrystal alloys was investigated in an artificial seawater (3.5% NaCl solution) environment. These samples were tested in electrochemical experiments to obtain a current density and a corrosion rate. The results revealed that chemical composition and microstructure determined the corrosive behaviors of quasicrystal alloys. Specifically, Fe-based λ-phase showed pitting corrosion; while Cu-based β-phase and icosahedral-phase exhibited corrosion resistance. In the case of multi-phased alloys consisting of quasicrystal, they showed various corrosive behaviors according to the combination of phases. The alloys with λ-phase led to the higher current density and corrosion rate displaying pitting, galvanic, intergranular, and crevice corrosion. Meanwhile, the alloys with i-phase produced the lower current density and corrosion rate, presenting only weak galvanic and crevice corrosion. Additionally, higher concentrations of i-phase improve the corrosion resistance of multi-phase quasicrystal alloys. The understanding of corrosion mechanisms in quasicrystal alloys will open the way for the development of metal alloys that can be used in marine conditions.