I seem to recall reading that its not a good idea to solder
palladium with an oxy/hydrogen flame The problem, as I understand
it, it "hydrogen embrittlement". Other's here can give you a
better explanation....David L. Huffman
Palladium absorbs hydrogen platinum doesn't you will end up
with porous solder joints....James Binnion
Since my firm has worked in this specific area, both in industrial
and jewelry applications, we have good experience in the specific
area of hydrogen embrittlement.
It should be noted that in actual practice hydrogen embrittlement
"is usually caused in high strength steel. Ordinary steel and
non-ferrous materials are usually immune." In both theory and
practice it is VERY UNLIKELY to produce hydrogen embrittlement in
the bench work stage.
It is theoretically possible in the melting/alloying process if a
considerable imbalance of gases are used, primarily an excess of
hydrogen. A significant (noticeable) excess of hydrogen is required.
Hydrogen embrittlement, again in high strength steel can also be
caused in harsh environments where hydrogen sulfide is present.
It is also possible to cause hydrogen embrittlement in a plating
process, again in high-strength steels, not precious metals. I refer
you to the work of Ken Russell, Professor Emeritus of Metallurgy and
Nuclear Engineering at MIT, and to the work of Tom Doppke and
So, for bench work, including palladium, hydrogen/oxygen is very
unlikely to cause hydrogen embrittlement. If you were using bottled
gases, you can produce an excess of hydrogen since it is not
possible to perfectly control the mix of hydrogen/oxygen to a
perfect two to one mix. With a hydrogen/oxygen generator the mix of
gas will always be two parts hydrogen to one part oxygen, and this
ideal combination will be consumed with no possibility of excess
hydrogen, or hydrogen embrittlement.
However, James Binnion is correct, when you braze or weld palladium
with a torch (not including inert filler gases) you will always have
surface porosity on palladium. This will occur with or without
hydrogen. Surface porosity is the actual concern. Surface porosity
and hydrogen embrittlement are two very different things. It is
fairly easy to produce porosity under many conditions. It is very
difficult to reliably produce hydrogen embrittlement. Many of our
customers using our Spirflame[R] hydrogen/oxygen generator allow
extra thickness when sizing or fabricating palladium, for the clean
up. They claim this clean up is less, than with others torches. I
prefer platinum to palladium and do not use palladium enough to
support or disagree with them at this time, on this one point. A
laser is also good solution with palladium, if opportunity allows
it. Sorry for the length of this reply.
Gary W. Miller, Sr. Technical Advisor
Spirig Advanced Technologies, Inc.