THE CORROSION BEHAVIOR OF SPUTTER-DEPOSITED AMORPHOUS W-TI ALLOYS IN 6M HCL SOLUTION

Amorphous W-Ti alloys were successfully prepared by DC magnetron sputtering in a wide composition range. The sputter deposited W-Ti alloys thus prepared were spontaneously passive, and their corrosion rates were lower than tungsten and about two orders of magnitude lower than titanium in 6 M HCl solution open to air at 30 degrees C. XPS analysis showed that tungsten was enriched in both the passive films and underlying alloy surfaces in 6 M HCl solution. The passive films on the W-Ti alloys were composed of a double oxyhydroxide of tetravalent tungsten and titanium ions. The formation of the double oxyhydroxide film seems responsible for high corrosion resistance of the alloys in comparison with alloying constituents in 6 M HCl at 30 degrees C.