I was not aware and don't think that processing
screens the way we did it was covered under ITAR
since we got it straight from a public book on
peroxide rockets and Erik Bengtsson from Peroxide Propulsion
We plated our 20 mesh nickel screens by first
cleaning the screens in an acid bath and then
thru a wash cycle. They then go into an
electro-cleaning solution, through some more
washes, then dipped in a pre-activation solution,
and we do a copper strike. Back into the acid to
etch the copper, back thru the cleaning baths
and then a silver strike at low amperage followed
by the silver plate at high amperage. We then
oxidize the silver with liver of sulphur and then
heat it in an oven to just below the melting
point, (see the following for the reasons,
http://www.peroxidepropulsion.com/article/18 ).
When the silver is cooled we then do another
quick acid bath and wash and then proceed with
doing the standard addition of samarium which
further enhances the catalization.
Although we have varied on timing and
temperatures the stripping problem has stayed
with us. In the end we have a relatively stable
high performing catalyst with two defects. It can
be poisoned and it tends to strip silver on long runs.
Presently I use plated screens processed similar
to above and runs less then 10 seconds in the
schools 1.5" motor. 1 quick pulse to heat the
pack will then give me a 10 second clean run.
BTW the school gets 23 liter containers of a
rather pure 90% peroxide which we dilute down to
85% for school demonstrations and after hour tests.
While we are on the Subject, does anyone have a
more detailed description of a monolith cat pack
like or similar to Aerojets cat packs?
Robert
At 05:38 AM 8/29/2016,
I want to respect proprietary processes--as well as ITAR--so I'm going to be a little vague:
It is my understanding that the silver is electroplated using a very different process than that conventially used for fine silver plating.
The Samarian Oxide process involves--as I have seen it--dipping of the screens for a specific period of time in a Samarian Nitrate solution that is kept at a specific temperature; that is followed by warm air drying--again, at a specific air temperature--followed by oven cooking at a specific temperature and for a specific period. This is repeated a number of times. Test samples are inspected via electron microscope to verify that the coating is the correct overall thickness and has the correct porosity.
Bill
On Monday, August 29, 2016, Uwe Klein <<mailto:uwe@xxxxxxxxxxxxxxxxxxx>uwe@xxxxxxxxxxxxxxxxxxx> wrote:
Am 29.08.2016 um 03:30 schrieb Anthony Cesaroni:
If the silver plating process
How is the plating actually done here?
galvanic? that will come off easily.
High current galvanics could improve on that.
what about molten powder application
    <https://www.castolin.com/>https://www.castolin.com/
or sputtering?
uwe
