New Cu-Zr-Al-Nb bulk glassy alloys with high corrosion resistance

Abstract

New Cu-based bulk glassy alloys with good mechanical properties were formed in Cu-Zr-Al-(Nb) system by copper mold casting. They exhibit a large supercooled liquid region (ΔTx) of 50 K-74 K and high glass-forming ability with maximum diameters of 2.0 mm-3.0 mm. The addition of Nb to the glassy alloys is effective for improving the corrosion resistance in all the solutions. The corrosion rate of the 5 at% Nb alloy decreases by one order of magnitude compared to those of the 0 at% Nb alloys in 3 mass% NaCl solution. In 0.5 mol·dm-3 H2SO4 solution, the Cu-Zr-Al-(Nb) alloys are passivated in wide passive region and low passive current density of the order of 10-2 A·m-2, indicating high corrosion resistance in this solution.