Hydrogen induced damage in pickled and anodized Ti--6Al--4V alloy surfaces

A study was undertaken to investigate a possible relationship between pickling time and the amount of hydrogen introduced in the pickling process. This paper describes the results of surface and bulk hydrogen analysis of Ti-6Al-4V alloy specimens which were pickled according to a predetermined schedule. Hydrogen content in the alloy increased with pickling time, but the rate of absorption was higher for shorter time tests (less than 2 minutes) than for longer time tests (greater than 5 minutes). Alkaline etching significantly reduced the hydrogen pick-up. Sufficient hydrogen in the alloy resulted in failure of the adhesively bonded oxide coating formed during a subsequent anodization treatment.