Abstract

New series of amorphous or/and nanocrystalline W–Zr–(15–18)Cr alloys are successfully prepared by direct current (DC) magnetron sputtering. The role of alloy-constituting elements on the corrosion behavior of the W–Zr–(15–18)Cr alloys is studied by corrosion tests and electrochemical measurements in 12 M HCl solution open to air at 30°C. All the examined sputter-deposited W–Zr–(15–18)Cr alloys containing 12 to 73% zirconium are passivated spontaneously, and hence they showed more than one order of magnitude higher corrosion resistance than those of alloy-constituting elements. The corrosion rate of the alloys is in the range of 1–2 × 10^–3 mm/y which is even lower than those of the sputter-deposited binary W–Zr and W–Cr alloys. The zirconium addition suppresses the anodic dissolution current, and hence the anodic current densities of the alloys decreased with increasing the zirconium content in the W–Zr–(15–18)Cr alloys. It is therefore considered that the simultaneous additions of zirconium and tungsten with 15 to 18% of chromium enhance synergistically the corrosion-resistant and pitting corrosion of the sputter-deposited W–Zr–(15–18)Cr alloys in 12 M HCl.

Key words: Amorphous/nanocrystals, sputter deposition, corrosion-resistant, W–Zr–Cr alloys, electrochemical measurement, pitting corrosion.