As I read the earlier post, the failure was not in the
platinum/palladium coating but in the underlying ceramic beads.
Automotive cat converters heat up and cool down relatively gradually so
surviving extreme thermal shock probably isn't a design requirement for
the catalyst's ceramic substrate. (Extreme parsimony with the actual
catalyst metals definitely is a design requirement.)
Just out of curiosity, anyone have a source and price on pure
platinum/palladium mesh or wire? On plated mesh or wire? It occurs to
me that it might be overall cheaper to bite the bullet and pay, say,
$10K per engine, than to put more time and effort into finding a cheap
alternative for HTP cat-packs when that's already soaked up so much time
and effort to no avail.
Henry
On 9/16/2016 5:14 AM, William Claybaugh wrote:
Randall:
Very clever, raiding catalytic converters. I'll look into exactly what
the car companies use; pure platinum / palladium should not have failed
at peroxide temps....
Just curious and OT, but could you see more than a bright dot? Wings?
Bill
On Friday, September 16, 2016, Randall Clague <rclague@xxxxxxxxx
<mailto:rclague@xxxxxxxxx>> wrote:
Hi Bill,
Not hardly; these were platinum/palladium beads scavenged from a
catalytic converter at a junkyard. Considering the difference in
mass flow between what they were designed to handle and what ERPS
asked of them, it's no wonder they were pulverized. It's a tribute
to automotive engineering that they worked for as long as they did
under those conditions.
I didn't know that about X-37, thanks. I did see one in flight.
10x50s from a Burbank back yard. 22 Dec 11, so that would have been
OTV-2.
-R
On Thu, Sep 15, 2016 at 1:33 PM, William Claybaugh
<wclaybaugh2@xxxxxxxxx
<javascript:_e(%7B%7D,'cvml','wclaybaugh2@xxxxxxxxx');>> wrote:
Randall:
I deduce from your discription that the Platimium / Palladium
was deposited on some sort of matrix and that the coating came
off under differential thermal expansion; yes?
The 98% peroxide thrusters developed--but not used--for X-37
used woven screens in more or less the conventional manner used
for silver. They worked w/o incident in testing.
Bill
On Thursday, September 15, 2016, Randall Clague
<rclague@xxxxxxxxx
<javascript:_e(%7B%7D,'cvml','rclague@xxxxxxxxx');>> wrote:
ERPS tested platinum/palladium beads in 1994. The beads
work fine in an ashtray, as ERPS demonstrated during their
talks at Space Access '94 and '95. (In '95 they scorched
the tablecloth, and they were asked not to repeat their
demonstration.)
Video of a test ERPS did with a platinum/palladium bead
catalyst pack shows that the exhaust starts out white, goes
clear, then turns tan. Post-test inspection showed that
many beads were crushed or absent. The tan exhaust was
interpreted as pulverized catalyst departing the engine, and
their hypothesis was that the beads lost structural
integrity due to thermal shock.
-R
On Wed, Aug 24, 2016 at 11:46 PM, William Claybaugh
<wclaybaugh2@xxxxxxxxx> wrote:
I'm pretty sure that Platinum / Palladium cat beds are
proven to work just fine and last forever running 98%
Peroxide.
Bill
