Corrosive behavior of multi-phased quasicrystal alloys

Abstract

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 lambda-phase showed pitting corrosion; while Cu-based beta-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 lambda-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. (C) 2020 Elsevier B.V. All rights reserved.