Effects of Si Additions on the Glass-Forming Ability and Corrosion Resistance of Cu49Zr45Al6 Bulk Metallic Glass

Abstract

Alloys with the compositions of Cu49-xZr45Al6Six (x = 0, 0.5, 1, 2, and 3, in atom percent) were prepared by sucking the melt into a water-cooled copper. The effects of Si additions on the glass-forming ability (GFA) and corrosion behaviors in 1 N hydrochloric acid (HCl), 3.5 mass% sodium chloride (NaCl), and 0.5 N sulfuric acid (H2SO4) solutions were studied. It was found that, by adding 0.5% to 1% Si to substitute Cu in the Cu49Zr45Al6 alloy, the GFA was promoted, but extensive Si addition (>1%) decreased the GFA of the Cu49Zr45Al6 alloy. The results of weight-loss measurements, electrochemical polarization tests, and electrochemical impedance spectroscopy (EIS) tests on the Cu-based bulk metallic glasses (BMG) with different Si additions revealed that the Si addition improves the corrosion resistance in 1 N HCl, 3.5 mass% NaCl, and 0.5 N H2SO4 solutions, especially in 1 N HCl. The improvement of the corrosion resistance may be attributed to the formation of a silica-containing inner layer.