13th June 2004 - 06:07 PM
I've read that there can be significant amounts of hydrogen entrapped in
certain common metal alloys (e.g. Kovar, aluminum, titanium, stainless
steel) from the fabrication process. Are there any good references on this
subject? Web resources? For a given material, can one estimate how much
will diffuse out over time at a given temperature?
I'd appreciate any leads on the subject.
13th June 2004 - 06:08 PM
There is a book VACUUM METALLURGY published back
in the 1950's which is an excellent introduction to the subject.
I gave away my copy, so I don't recall what it had to say about
hydrogen. However, refining metals under vacuum to pull out
the gases was a critical development in the evolution of
high-performance metal materials, such as jet engine turbine
blades. The very first industrial use of this technique was in the
refining of tantalum for lightbulb filaments in the early 20th
century, but its use didn't really take off until WW2 and the
13th June 2004 - 06:08 PM
There are frequent data compilations on diffusion of hydrogen in metals
in "Diffusion and defect data" series, SciTec Publications.
There you can also find information on hydrogen uptake during the
13th June 2004 - 06:09 PM
The subject "Hydrogen Embrittlement" relates to the solubility of
hydrogen in metals. It is a pretty old topic. Has killed many people and
great loss of property.
For web resources just type in the right keywords like:
"hydrogen solubility iron"
"hydrogen diffsuion metal"
"Hydrogen diffusin iron"
and so on.
Library search books the word "Hydrogen" in the title.
8th March 2008 - 07:36 PM
For high strength - carbon containing - steel, hydrogen embrittlement is an issue at high pressures (> 50 bar) for longer lifetimes. One approach to solve this problem could be lining or coating with a polymer. However, according to the attached paper, the polymer or composite does not help much. I am curious what you think of the paper or possible solutions from the side of metal engineering.
Looking forward to hearing from you.
8th March 2008 - 09:12 PM
Hydrogen is a group 1 metal - albeit at super high pressure, therefore shouldn't this thread be called "Replying to alloys"?
10th March 2008 - 03:25 AM
This question has been very extensively treated. Google "hydrogen embrittlement".
I consider that far too much time has been wasted on this subject. A typical case where one makes research just because other people have made some?
Bake you metal parts for 10 min at 200°C if you had an electrochemical or acid processing step on them, and the hydrogen is gone (exodiffused).
Why should you want to know how it got in, what the effects are and so on, since its so easy to get rid of it?
Man, we lack really basic observation data for coefficients of friction, for seizure and mating... Every book, every teacher repeats the same false facts and explanations there, leading to engineering mistakes. Research there would be more useful!