Neme
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Lead dioxide anode on less common substrates
With vision of better substrate for lead dioxide anode, as graphite nor titanium are ideal, I have been searching for more exotic substrates. However
I struggle to find nearly any usefull article. Initially I had an idea of tungsten or molybdenum substrate as they are readily accesible.
So I'm asking if any of you have experiences with uncommon substrates and if I should stick to graphite/titanium instead of trying other substrates.
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phlogiston
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No actual experience, but I recall niobium and tantalum being mentioned in the literature on this topic. I'm sure it shouldn't be hard to find more
information on those.
I doubt they offer many advantages though, given that they seem to be not commonly used (if at all?).
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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Heptylene
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What is the problem with graphite? Titanium passivates, which is a problem, but graphite doesn't. Plus graphite is cheap, available in thin plates and
is unreactive.
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AlexC
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They don't know and you'll never know. 10 years ago I was hoping that at least here I will find a solution, and nothing. Nobody ever discovered what
is problem. Of course, problem is that graphite erodes, somewhat too fast. And that is not problem in most cases, because it's cheap and can be
replaced periodically.
But really why graphite erodes? Is it something chemical, electric or physical? Is it because of O or Cl only? Is it because graphite is soft anyway
and physical disturbances (micro balloon explosions) cause it to erode? Or some compound appears at surface that reacts?
Nobody, not even NurdRage ever discovered and solved that problem. Nothing will be discovered for next 10 years. Except If I don't take things into my
own hands, under my control. Talking is not enough. Most people are just talkers. I mean few tries would solve that mistery.
Graphite is good at cathode, 100% resistant. I mean, we can already conclude that electric current or gas balloons explosions are not the cause. It
must be something with Cl or O? Actually I believe cathode is not resistant if high enough electric current is made. It should produce methane instead
of H.
One problem is graphite's mechanical weakness and electric resistance and lot more.
[Edited on 13-7-2018 by AlexC]
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Heptylene
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@AlexC are you talking about plain graphite anodes or lead dioxide anodes on a graphite substrate? AFAIK only plain graphite anodes have erosion
problem, I never heard about lead dioxide on graphite substrate having that problem.
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NeonPulse
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There are a few people who have tried to make anodes using PVC as the substrate. Firstly they dipped it he plastic in MEK or acetone to soften it and
it is then dipped into Lead dioxide powder to cover as much as possible and then it is plated in a final coating of lead dioxide. Another attempt was
done using Lead dioxide and an epoxy resin thoroughly mixed and shaped into a bar which was also finished with another coating of PbO2. Not sure about
how well they held up though. The idea sounds good in theory but a perchlorate cell is pretty hard on the anodes so they may fail or they may work
well.
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Cipher
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What is problem with this? I thought that Pb will not have problems like Mn. Weren't PbO2 anodes always doing it's job in car batteries? Are you not
aware that using anything but metals will give you bigger electric resistance? We don't want that.
Are you saying that problem is with PbO2 not adhering to common metals? Just like MnO2? Or that it is flaking as NurdRage said?
But if it is found in car battery, it means it is doing well there. So why not use Pb electrode? I mean not whole electrode has to be Pb, but maybe
some conductive cheap common metal coated with Pb then with PbO2? Is this good solution?
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