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-----Is Ti Hydrogen Embrittlement Reversible?
Hi:
How do I reverse hydrogen embrittlement?
For perchlorate electrolysis in a filter press type electrolyzer I use 1mm thick titanium sheets with platinum on one side (anode) and bare titanium on the other (cathode. Several of these bipolar electrodes are spaced out in PP frames to form the electrolyzer.
All is well when I assemble the electrolyzer with new plates. But after a few weeks of use, I need to open the electrolyzer for some problem or the other (e.g., leakage. The bipolar electrodes come out very brittle and bowed (bent). It is impossible to reassemble.
Any suggestions what I should do ? Heat treat ? How? And after so many weeks will it work ? Plate the cathode side ? With ? Or ? Suggestions ?
- Mumbai, Maharashtra, India
2003
Hydrogen can be removed from titanium by heating at 1200-1500 F in vacuum. However, hydrogen embrittlement damage is not reversible. From your description, considerable titanium hydride formation has occurred, with destruction of the titanium microstructure. A recent study where titanium was cathodically charged in 0.05 M sulfuric acid for 55 & 83 hours showed considerable cracking due to the increase in volume from a TiH surface layer. -- K. Azumi et al., J. Electrochem. Soc., Vol. 149, pp. B422-B427 (2002).
I am not familiar with your process, but suggest a change in material. You could try an inexpensive metal that might require flushing out your system whenever the current was off, or use a more expensive material such as a super austenitic stainless steel, e.g.,
20Mo-6® (N08026). An Internet articles on electrolytic formation of perchlorate states "Like in chlorate cells, stainless steel is a suitable cathode material. Mild steel may also be used." http://www.poortour.com/build/pyrotechnics/perchlorate.html
- Goleta, California
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2003
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