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Author: Subject: More on PbO2 electrodes
hashashan
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[*] posted on 17-1-2008 at 16:01


Well my cell finished his run, a bit late but its ok. Positive with MB test.
And then came the stage to destroy the chlorate ..... Never had problems with that but now god damn ..... just cant destroy them. The sulfite method doesn't work, I don't get the SO2 smell, get positive with the manganese sulfate and phosphoric acid test and really really positive with IC test(I wonder if anyone got negative with it )

I thought that maybe my problem is that the Mn test hits positive because of the persulfate added in the beginning ... anyone got ideas what to do?
the liquor is now flooded with HCl and Na sulfite already crystallized out of it.
Im desperate.... meanwhile started another run without the persulfate just to see what happens

@dann : it works like charm

[Edited on 18-1-2008 by hashashan]
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[*] posted on 17-1-2008 at 16:39


If it's "loaded with acid", the chlorate is present as HClO3 (pH < 1 or so) and decomposing to Cl2, which should more than oxidize any sulfites present (at this pH, H2SO3). So if it doesn't smell like SO2 on further addition, that's weird, but if it also doesn't smell like Cl2 (assuming it is acidic enough), there's nothing to worry about.

Tim




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dann2
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[*] posted on 17-1-2008 at 17:00


Hello,

I used a stirrer. The anode was really just a 'prerun' as I had no idea if LD would even stick to Mangetite. I did not even round the edges of the Ti as I had no idea if the Magnetite would form in the first place!
Magnetite is a bit of a pain in the ass to put onto Ti but it may make a rugged anode (may not!!)

Cheers,
Dann2.
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dann2
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[*] posted on 17-1-2008 at 17:15


Quote:
Originally posted by dann2
Hello,

There is an artical here about the use of CTAB in plaitng baths.


Dann2


Hello,
I cannot find this article. Does anyone have it?

I remember reading it but for some reason or other it is not on my pc (or here either). Perpahs it was a top secret, self destruct file :o

I have Silicone Carbide. Would I be right in assuming it will not be attacked in a LD plating tank if used as the ceramic particles?

Cheers,
Dann2

[Edited on 18-1-2008 by dann2]
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tentacles
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[*] posted on 17-1-2008 at 17:45


I'm going to try making an ATO solution and put a couple coats of DTO over the Co spinel I put on a second piece of ti (the one I have been using to plate PbO2). After this I am going to try plating PbO2 over.

I put a few coats of (possibly?) Bi doped MnO2. 5% bismuth (as metal) onto Betty. I should really dunk that b*tch into some chlorate soon!

[Edited on 17-1-2008 by tentacles]

[Edited on 17-1-2008 by tentacles]
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jpsmith123
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[*] posted on 17-1-2008 at 18:45


Dann2 are you talking about the article that has this paragraph:

The addition of different surface active agents to avoid pinholes has been described previously (13, 14, 25-27). In the course of the study on measurements of stress in electrodeposited lead dioxide(28), the authors found the addition of quaternary ammonium surfactant not only lowered the stress but also helped in obtaining a pore-free deposit on stationary graphite even at higher current densities(29) . An example of q.a.surfactant is Cetyl Trimethylammonium bromide also called Hexadecyltrimethylammonium Bromide. Use 2-3 grams per liter.

If so, it's here:
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
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hashashan
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[*] posted on 18-1-2008 at 08:52


But is there any reason that I get positive with the Mn phosphoric acid test? (that small amount of persulfate can differ?)
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tentacles
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[*] posted on 18-1-2008 at 10:11


hashashan: I had a similar problem with the liquor I ended up with after I ran that other LD anode. HCl and sulfites didn't seem to cause any reactions. Have you tried sugar + H2SO4 to test for chlorates?

dann2: CTAB, and there was another surfactant discussed somewhere, seems to be quite hard to find. I think JTBaker has it, for like $25/15g or something. I believe a few articles have mentioned using a nonpolar agricultural surfactant. I've been wanting to try the agri surfactant but the fertilizer shop doesn't have KNO3 in yet this year so I've been waiting. One problem with the sufactants is that they decompose over time in the plating tank, so the lifetime of the plating solution is somewhat limited. Still, there are ways that the lead could be recycled and the stress relieving effects are probably worth it.

[Edited on 18-1-2008 by tentacles]
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hashashan
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[*] posted on 18-1-2008 at 11:15


@ tentacles : not yet, I didn't dry the crystals yet. However that is a crappy test
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dann2
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[*] posted on 18-1-2008 at 12:39


Hello,

Thankks for replies.
@Xenoid That is not the articlal. The artical goes into detail about the way CTAB is used up as LD is plated.
I just wanted it for completness. Have no idea how/where it dissapeared to.

I agree that adding Surfactant complicates things + price.

Dann2
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tentacles
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[*] posted on 18-1-2008 at 20:52


dann, Was that the article/patent where massive PbO2 was plated on niobium? I've been looking for that one in the time since I've read it, and I seem to recall some discussion about different surfactants. Igepal CO-880 or something, and a random agri nonpolar.
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[*] posted on 18-1-2008 at 20:52


dann, Was that the article/patent where massive PbO2 was plated on niobium? I've been looking for that one in the time since I've read it, and I seem to recall some discussion about different surfactants. Igepal CO-880 or something, and a random agri nonpolar.
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dann2
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[*] posted on 19-1-2008 at 13:35


Hello,

Patent here for massive anode on Ta (if thats any use).
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
(around middle of page)

Found it. Perhaps I may have never read the artical? only seen the reference:
https://article.pubs.nrc-cnrc.gc.ca/RPAS/RPViewDoc?issn=1480...
Consumption of Cetyl Trimethyl Ammonium Bromide (CTAB) during Electrodeposition of Lead Dioxide
Kapisthalam Chetlur Narasimham, Srinivasaraghavan Vasundara, Handady Venkatakrishna Udupa
Canadian Journal of Chemistry 53 pp 3327-3329


If you google ' lead dioxide ctab ' it will come up (and more).

Not really wanting to use CTAB just to read and perhaps learn something.

CTAB can be had on ebay.co.uk if anyone wants it.
The CTAB thing seem to be a whole religion if its own!!!!!!!
There is even a http://www.ctab.org.uk LOL
Applications are mouthwashes, losingers and antiseptics.

(and of course mad anode making)


@Hashashan
Did you try heating the solution when destroying Chlorate.

Dann2

[Edited on 19-1-2008 by dann2]

[Edited on 19-1-2008 by dann2]
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hashashan
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[*] posted on 19-1-2008 at 16:15


brought it to boiling .. and added all the sulfite to the boiling solution.
It did look like some reaction happened ... but yet I added tons of sulfite and still positive on the Mn test.
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tentacles
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[*] posted on 19-1-2008 at 21:19


I tried putting a couple coats of DTO on my Co Spinel coated strip today, the color is different now but I'm not entirely sure if it is a good coating. I also burned ou my damn heat gun, it'll be going back tommorow for a replacement. I almost set the anode up in the LD tank today but I'm still "recharging" it with lead and need to top off the water and filter out the copper and crap.
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[*] posted on 19-1-2008 at 23:07


I am not sure on which of the half dozen threads this originated, but this one is as good as any to insert this....

A RETRACTION

Dann2 recently reminded me that I had promised to estimate whether the sample of “perchlorate” I claimed to have made by electrolysis on a carbon anode was, in fact, perchlorate. I have been lax in this due to attention to other business (to whit, the damned stock market). I have now performed what tests I can, and state:

To the best of my knowledge, perchlorates CANNOT be produced by the electrolysis of chlorates using carbon as an anode.

I had two samples, produced in 1995. One, labeled Chlorate (call it ‘C’ for short) was produced by electrolysis of saturated NaCl using a carbon anode. Part - the major part – was used by metathesis with KCl to produce KClO3.

The rest was then somewhat purified to get rid of as much NaCl as possible and subjected to further electrolysis, following a convincing sounding procedure “guaranteed” to produce perchlorate (found somewhere on the WWW). I added KCl to the electrolyte at this point order to precipitate any KClO4 so formed. I kept temperature much lower (by reducing current density and ohmic losses) than in the first case, since I assumed the process was a purely electrochemical ion oxidation conversion, with a different cell configuration (wide anode/cathode separation). A precipitate was formed.

This was bottled as ‘KClO4 (impure)’ – call it sample ‘P’. The only use I ever made of this was to demonstrate a few pyrotechnical reactions to my younger son. It seemed less reactive than the sample C.

When Dann called into question its composition, I sought methods available to me to determine this. I did not have conc. H2SO4 available nor Methylene Blue.

Chlorates react with any strong acid to give either Cl2 or ClO2 or a mixture; perchlorates do not, due to the kinetic barrier which accounts for their relatively poor oxidation performance, although the thermodynamics favor it over chlorates.

(1) A test of P with HCl gave off a gas that was either Cl2 or a mix with ClO2, by nose test. Conclusion: P contains Chlorate. This does not definitively say it does not contain perchlorate, however.

(2) Saturated solutions were made of both samples and a drop placed on a microscope slide and allowed to evaporate slowly. Crystallization was observed under X50 mag.

Result: C gave lozenge shaped crystals characteristic of KClO3, plus a few needles. Both of these forms are possible under the monoclinic classification of KClO3, where sides may be unequal but parallel and only one angle is a right angle.

P also gave the same shapes in the main – only one crystal was orthorhombic, where all angles are right angles, but sides unequal (unlike cubic) which is characteristic of KClO4. However, needles were also produced, and perchlorate can also be of the needle form (it is isomorphic with KMnO4, which tends to make needles in my experience).

Conclusion: If there was any perchlorate in P, it was a small amount.

(3) 1.000 g (+- 0.005g) of each of C and P were dissolved in 33.3 mL (+-0.3mL) water at RT – both dissolved. This shows that less than 70% was perchlorate. The solution was so chosen that pure chlorate would be just saturated at 0c. Both solutions were cooled for 3 hrs. in a water bath in a refrigerator to slow the ice melting. One or two small crystals were then seen floating in C; none in P. The P solution was somewhat turbid at the start and a fine white ppt. settled during cooling, but there was very little of it. Examination under magnification showed what looked like particles of a fibre. Non –crystalline.

The conclusion from test 3, (solubility) indicates that not more than 0.25g in solution (<25%) could possibly be perchlorate. Taking account of the common ion effect, even including activity coefficient (from CRC) reduces this to a maximum of 0.063 g (<6.3%).

Overall conclusion: if perchlorate was formed at all, it was probably less than 5%. I was merely oxidizing carbon! Moral: Don’t believe what you see on the web, however convincing. And do some tests, always…

You were right, Dann!

Regards,

Der Alte
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[*] posted on 19-1-2008 at 23:22


@ DerAlte

Should have gone in the "Perchlorate manufacture (not) with Graphite thread ... :D

Try an aquarium shop for some 3% Methylene Blue, they use it for treating fish diseases, this would finish off your proof!
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[*] posted on 19-1-2008 at 23:58


Yes, not with...

Have no use for perchlorate myself. It's rather boring, apart from pyrotechnics. However, your efforts to produce the MMO, etc, Anodes are very impressive.
Der Alte
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[*] posted on 20-1-2008 at 06:03


Hello,

@DetAlt It is good to put the 'Perchlorte from Graphite' thing to bed once and for all!


@Tentacles Did you drill lots of holes in the Ti . It is a very good (I think!) way to help the Lead Dioxide to stay in place.
What is you DTO recipe??
Hope it is <strike>not</strike> similar to the Diamond Shamrock patents!!!!!!!:P

Dann2

[Edited on 20-1-2008 by dann2]
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[*] posted on 20-1-2008 at 07:01


Quote:
Originally posted by DerAlte
Yes, not with...

Have no use for perchlorate myself. It's rather boring, apart from pyrotechnics. However, your efforts to produce the MMO, etc, Anodes are very impressive.
Der Alte


Oh man perchorates boring?! You let me down man.:( Ammonium perchlorate is easily converted to perchloric acid for which metal perchlorates can be made. I had a nice nickel deposit from a nickel perchlorate solution I electroyzed with no buffers or additives.

Don't forget potassium perchlorate's role in Self-Propagated High Temperatures reactions. This was mostly researched by the Russians so finding english papers takes a little sleuthing work.

Perchlorate occupies roles that chlorate is unable to do to the inherent dangers of instability.

[Edited on 1/20/2008 by chloric1]




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dann2
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[*] posted on 20-1-2008 at 09:54
Substrates standing by, ATO on it's way.....


Hello,

Some examples of drilled Ti substrates. Will be ATO'ing + LD'ing once I get my Sodium Potassium Tartrate for the Alpha LD plating bath.
Substrates in picture have yet to be etched. Will not be sand blasting as I don't have a sand blaster or access to one.

I wonder if you were to take a new clean wire brush and with the Ti on a firm bench, strike the Ti with the points of the wire on the brush a number of times. Would this rough up the surface like sand blasting would?



Some of these's substrates are very thin as they have been etched many times.

Dann2
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tentacles
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[*] posted on 20-1-2008 at 10:45


dann2: I'm attempting ATO using 95/5 solder, HCl + H2O2. The tin dissolved fine, left the characteristic antimony trioxide, added a splash of H2O2, and the reaction was VERY vigorous, like adding carbonate to strong acid. The color of the strip changed from the Co spinel shade of grey.

I wouldn't recommend using a wire brush, it could leave bits of steel or stainless embedded in your Ti. I did not drill my strip, although I suppose I still could. Problem is, my heat gun is down until I take it back to canadian tire, so I'm up a creek on plating it today if I do drill it.

One thing I have been wondering is, what would be an appropriate method to connect the power to the anode? I am planning on attempting to silver plate the end of the strip, see how that goes.

I've been prepping the LD tank today, going to concentrate it down to 1L (~500g/l PbO2) and give 'er a go.
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[*] posted on 20-1-2008 at 11:29


I use an extra length of titanium strip and bolt a copper strap onto the end.

The wirebrush I have doesn't do much to titanium. It's hard shit!

Tim




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hashashan
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[*] posted on 20-1-2008 at 12:01


I just sanded with sand paper mine .... it works ok .. makes it shiny
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[*] posted on 20-1-2008 at 19:24


Hello,

Seems to be hugh differences in the hardness and corrosion resistance of Ti when you go from cp Grade 1 (Dann2 + Hashashan) to cp Grade 4 (Tim).
The Grade 1 (my stuff) etches easily in hot HCl and is quite soft.
Tim's stuff in semi indestructable.

Perhaps the stuff you have Tim has been processed in some way (heated?) and ours has not?

Perhaps the Grade you/I think we have is not correct.
I purchase mine on ebay as CP Grade one, but I cannot be 100% sure if that is what it is. The seller had no reason to tell me it was anything else.
Would it be possible that you have perhaps a grade that contains Palladium (0.015%) for extra corrosion resistance?

There is data here for Ti corrosion. They do not state grade so not much use. It is interesting to note that under 'Nitric + Hydrofluoric' they say "not recommended"?
The Nitric + Hydroflouric is what is used for cleaning stainless steel and is available in welding shops
Br seem to be good!
http://www.titaniumprocessingcenter.com/data.php

Also pdf on corrosion here:
http://www.timet.com/coresistframe.html



@Tentacles: With 5% Sb in your ATO I am going to have to 'think of England' while you are making the anode. :D

Dann2

[Edited on 21-1-2008 by dann2]

[Edited on 21-1-2008 by dann2]

[Edited on 21-1-2008 by dann2]
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