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Author: Subject: More on PbO2 electrodes
Eclectic
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[*] posted on 20-6-2007 at 09:52


Make sure your solution is still very acidic after neutralizing the ammonium. Extra HCl won't cause any problems. Maybe add a bit of hydrogen peroxide (BEFORE you've added any ether, you don't want to make ether peroxides) to discharge the blue color, evaporate ether extracts to dryness. You get tungsten and molybdenum blues under reducing conditions with these polyacids. Maybe the ammonium is acting as a reductant?

I'm extrapolating from a procedure I've used to make silicotungstic acid, which is over 80% by weight soluble in water to make a liquid with a density over 3. Great for flotation separation of minerals with slightly different specific gravity, ie: quartz and beryl.

In any case, even if the stannomolybdic acid is not as soluble in ether as silicotungstic, if you've gotten everything completely solublized, you should be able to take some of your resulting solution, add the proper amount of tin compound to get your mole ratios correct, paint it on and give it a try. The extra HCL and ammonium ions will evaporate at the baking temps.


I plan on going with the 95/5 solder dissolved in concentrated HCL with a bit of peroxide and ammonium bifluoride added. I don't think the bifluoride is needed, but it won't hurt, and I have some.



[Edited on 6-20-2007 by Eclectic]
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[*] posted on 20-6-2007 at 10:09


A mixture of stannous and molybdenum fluoborates might solve the interactivity problem and produce a good dispersion of the two oxides when baked.....if the additional doping by boron and fluorine is not a problem ....and it might even be an enhancement .
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[*] posted on 20-6-2007 at 12:29


Actually, the only critical thing here is likely just the need to have everything solublized, with nothing unwanted in the solution that will remain in the finished baked coating. Preforming the stannomolybdic acid just ensures solubility of the molybdenum and avoids the formation of insoluble molybdic oxides. The ether extraction is not needed, and may not work for stannomolybdic acid like it does for silicotungstic (where the silicon comes from sodium silicate).

Sorry if the ether extraction turns out to be a blind alley. Lots of interesting variables to experiment with here.
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[*] posted on 20-6-2007 at 15:20


Hello,

Will try to do this with the refluxed Tin/Moly.
Thanks for help.


The cut from below is from US 4,028,215 Example 13
__________________________________________

A strip of porous titanium having a surface area of approximately 7 square inches (45 square centimeters) was coated with a solution of tin and antimony compounds by use of a vacuum to suck the solution through the porous material. The solution consisted of 5.27 grams of stannous sulfate, 2.63 grams of antimony trichloride, 10 milliliters of hydrochloric acid, and 20 milliliters of butyl alcohol. This was done four times with the baking of one-half hour at approximately 500.degree. C. between each pass through the porous titanium material. A 50 percent aqueous solution of manganese nitrate was passed through the material in the same fashion with a baking between each pass of 45 to 60 minutes at approximately 200 degrees centigrade until a weight gain in the range of 3.36 to 3.56 grams of manganese dioxide is contained therein.
______________________________________

It uses Stannous Sulphate (as opposed to Stannic Chloride as in all other examples).
I presume this is a typo in the patent???

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[*] posted on 20-6-2007 at 15:25


H2SO4 or SO3 will also probably evaporate out of the coating compounds at 500C, leaving just the mixed oxides.

You sure do come up with some good patent references. :)

[Edited on 6-20-2007 by Eclectic]
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[*] posted on 20-6-2007 at 15:35


Quote:
Originally posted by hashashan
i believe that i can make some PbO by fusing Pb and NaNO3 (btw do you think that a simple gas burner will do the work?)

and just got another thought. why not to use lead as the temprorary substrate? or maybe even lead coated with the alpha layer of PbO2 (that wouldnt have to be so strictly controlled PH)

Hello Hashashan,

I tried this and it works fairly good. Enough heat to melt the Lead is all you need. A gas burner is plenty, it may heat too much. Put a tray of sand about a quarter or half inch in dept between the burner and your reaction vessel to keep heat more controlled. I used a stainless steel soup bowl as the reaction vessel. Plenty of stirring.
You will be adding lots of Nitrate. Far more than the stoioc. amound as I presume lots of the oxygen escapes. A suction filer system would be great as you can then pour lots of water though you PbO to get rid of the Nitrate/Nitrite.
You will stirr the whole lot up first in a fairly large vessel with water and decant the suspended PbO to get rid of unreacted Lead.
Is your Lead pure. You could try measuring its melting/solidification temperature to see is it at the melting point of pure Lead.

If you are going to go down the pH controlling path I would suggest using two tanks and a pump.
If making massive anodes (temporary substrate) you could try rapping/attaching a cloth (or scoth scrubber) to the substrate so that the Lead Dioxide will grow and envelope the cloth and you may get a reinforcing effect.
Massive anodes will need a GOOD plating set up.



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[*] posted on 20-6-2007 at 15:41


Quote:
Originally posted by Eclectic
H2SO4 or SO3 will also probably evaporate out of the coating compounds at 500C, leaving just the mixed oxides.

You sure do come up with some good patent references. :)

[Edited on 6-20-2007 by Eclectic]


Hello,

You sure answer posts quickly :D

So you think we could use Stannous Sulphate instead of Stannic Chloride (5H2O or the dry stuff). Stannic Chloride is not easily got or made.
Perhaps Stannous Sulphate is just as difficult. It's back to the search engine for me...........

I think Rosco posted the patent first actually.




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[*] posted on 20-6-2007 at 16:04


I think your best bet is just dissolve 95/5 solder in 12N HCl with a small amount of H2O2 added to help the reaction along and avoid SbH3.

It's no problem to dissolve tin in HCl.

The sulfates are going to be more resistant to decomposition and evaporation of H2SO4 and/or SO3, and will be less soluble in organics. The butanol is maybe to lower solubility, increase evaporation rate, and possibly avoid dissolving away the layer you just baked on in the previous step?

Ok, I'm doing a proof of concept experiment: 125g of common 95/5 solder (approx 1 mole Sn) in 3-4 inch lengths siting in a loosely stoppered flask with 250 ml common muriatic acid (approx 3 moles HCl). It's fizzing merrily without heating up too bad or foaming up out of the flask. More later... 1 hour later 100ml more HCl added and flask transfered to coffee maker hot plate. The reaction isn't going to run away with some heat added to speed it up...6 hours later reaction has slowed down. Most of the solder has dissolved with brown-black precipitate remaining. Cooled and decanted clear liquid, added 200 ml muriatic acid to residue and slowly added dropwize 25 ml 30% H2O2 with stirring (caution, much heat and boiling if added too fast). Heating on coffee maker hotplate continued until everything has dissolved (1 hour). This liquid was combined with the previously decanted liquid and placed in a glass bowl over boiling water to reduce the resulting clear light yellow solution to a smaller volume.

I had to cool the solution so I could add a further 100 ml 30% H2O2 and 100ml HCl. It looks like SnCl2 reduces SbCl3 to something insoluble (same brown-black precipitate). When you've added enough H2O2, the solution turns chlorine green and the precipitate dissolves.

[Edited on 6-22-2007 by Eclectic]

I was able to evaporate the solution to about 200ml before it started to crystalize on the steam bath. I diluted this to 400ml with more muriatic acid (31.5%HCL). Figured as SnCl4.5H2O, this shoult be ~350g in 400 ml solution, with 5% by mole Sb.

If I needed to do this again I'd treat the clear solution from the initial dissolution of solder in HCl with dropwize addition of H2O2 and stirring before adding to the dissolved residue solution.. I estimate 75 ml would be needed. If you start the whole process with mixed HCl, H2O2, the dissolution of the solder will boil violently, and most of the peroxide will be wasted in catalyzed decomposition.

By adding H2O2 dropwize as the reaction proceeds, you end up with a solution of SnCl4/SbCl3 instead of SnCl2 and brown-black precipitate.




[Edited on 6-22-2007 by Eclectic]

[Edited on 6-23-2007 by Eclectic]

[Edited on 6-23-2007 by Eclectic]
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[*] posted on 21-6-2007 at 00:16


Quote:
Originally posted by dann2
Quote:
Originally posted by hashashan
i believe that i can make some PbO by fusing Pb and NaNO3 (btw do you think that a simple gas burner will do the work?)

and just got another thought. why not to use lead as the temprorary substrate? or maybe even lead coated with the alpha layer of PbO2 (that wouldnt have to be so strictly controlled PH)

Hello Hashashan,

I tried this and it works fairly good. Enough heat to melt the Lead is all you need. A gas burner is plenty, it may heat too much. Put a tray of sand about a quarter or half inch in dept between the burner and your reaction vessel to keep heat more controlled. I used a stainless steel soup bowl as the reaction vessel. Plenty of stirring.
You will be adding lots of Nitrate. Far more than the stoioc. amound as I presume lots of the oxygen escapes. A suction filer system would be great as you can then pour lots of water though you PbO to get rid of the Nitrate/Nitrite.
You will stirr the whole lot up first in a fairly large vessel with water and decant the suspended PbO to get rid of unreacted Lead.
Is your Lead pure. You could try measuring its melting/solidification temperature to see is it at the melting point of pure Lead.

If you are going to go down the pH controlling path I would suggest using two tanks and a pump.
If making massive anodes (temporary substrate) you could try rapping/attaching a cloth (or scoth scrubber) to the substrate so that the Lead Dioxide will grow and envelope the cloth and you may get a reinforcing effect.
Massive anodes will need a GOOD plating set up.



Dann2


The PbO process wasnt good' i added about 3 times more NaNO3 then needed and still not even half of the lead reacted(decided to continue the normal route) ill make some Pb(OH)2 from the nitrate and thats it.

About the lead subtrace anode, i will try it as soon as ill make all my reagents. ill coat the lead with lead dioxide (beta) with the sulfuric acid method. and then attach a cloth(of course i wanted to do so) and grow a massive anode over it.

About the two tanks, Any good method recommended(i only have about 1 literr of concentrated lead nitrate solution(and i dont want to make any more of it) also i have only one pump(if it wont dissolve :) ) the pump isnt contollable in any manner. i thought to use an flask with one pipe going to the bottom where ill have the lead hydroxide(oxide maybe? or any other suggestions)) and another pipe from the top will go back to the solution. near the plated anode(so the little water jet will also wash the bubbles away from the anode(thus i wont need a vibrator).
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[*] posted on 21-6-2007 at 03:22


I gave it a thought. If i am planning to use some PH controll(i still would like to hear some details about it) then i dont see any reason to use a temporary metal substrate, i will just use graphite.
ill sand down some gauging rods flatten their surface, after that ill arrange them in a way i want to and glue them together, stratch some fabric over them and then ill plate them over, erode the graphite away and ill have a nice anode.
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[*] posted on 22-6-2007 at 16:45


Quote:
Originally posted by Eclectic
Make sure your solution is still very acidic after neutralizing the ammonium. Extra HCl won't cause any problems. Maybe add a bit of hydrogen peroxide (BEFORE you've added any ether, you don't want to make ether peroxides) to discharge the blue color, evaporate ether extracts to dryness. You get tungsten and molybdenum blues under reducing conditions with these polyacids. Maybe the ammonium is acting as a reductant?

[Edited on 6-20-2007 by Eclectic]


Hello,
Soluion is pH 0. I added some H202 and the opaque blue/black solution turned a yellow colour whit a blue ppt.
Decanted off yellow liquid and extracted with Diethyl Ether. There is nothing visible in the ether. Will try evaoprating to dryness.
Is there anypoint in drying the yellow liquid to dryness and using whatever is in it.

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[*] posted on 22-6-2007 at 16:47


Quote:
Originally posted by hashashan
I gave it a thought. If i am planning to use some PH controll(i still would like to hear some details about it) then i dont see any reason to use a temporary metal substrate, i will just use graphite.
ill sand down some gauging rods flatten their surface, after that ill arrange them in a way i want to and glue them together, stratch some fabric over them and then ill plate them over, erode the graphite away and ill have a nice anode.


Hello,
I have never used pH control.
A word of advice I can give is to make small anodes so that pH and Lead Ion conc. will not vary too much.

Dann2
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thumbup.gif posted on 22-6-2007 at 20:05
100g / liter HNO3 plating bath for beta PbO2


The patent US4026786 describes a PbO2 plating method that could be useful , as it can be much easier to maintain a very low pH which is less sensitive to changing composition during plating , than to maintain a pH much nearer neutral where a very small change in composition causes a drastic change in pH . There can also be other advantages .

For more advanced work .....
The high level of acidity could also simplify the automated maintenance of both the Pb(NO3)2 concentration and pH ,
by means of recirculating the electrolyte across a sacrificial
sheet Pb anode which is energized by an adjustable low voltage ....the voltage level of which could be regulated
automatically by an op amp controller to hold the composition of the electrolyte constant . Conductivity could be sensed by a very low voltage conductivity probe . An automatic controller would probably not be too difficult to design nor expensive to build . I believe that very likely
such an automatic controller is used on the commercial plating equipment , even though no details are provided concerning such equipment , in these patents . It just makes sense that such automated process regulation is being used where larger scale and production quantities of anodes are being made .

Also concerning the preparation of Titanium for plating of
conductive coatings .....aside from the various brute force
methods of grinding and sandblasting , there is an alternative which has been mentioned , generally callled cathodization , or "hydriding" ....where the substrate is made a cathode in an acid solution and run for an extended time at a level of vigorous hydrogen evolution which scours
away and reduces any oxides and leaves a very clean metallic surface ...ready to receive a conductive coating which should be applied immediately ....before any significant
dielectric oxide layer can form . Some comparisons of the
usefulness of cathodization of Titanium as a preplate treatment with other methods of "etching" ect. are described in another patent US4153742 . This preplate cathodization
can even be continued with a plating of the actual free metal
precursor of the same metal whose oxide is then formed
when the polarity is reversed .....so that initially for example
there is a substrate metal to plated metal interface , which
can improve adhesion and conductivity . This hydriding and metallic lead flash preplate technique is possibly better than nothing , if a bare titanium substrate is to be used as above with the acidic Pb(NO3)2 bath .

The alternatives are the Ruthenium , or Tin - Antimony ,
or perhaps MnO2 - Co3O4 intermediate layer methods .

Attachment: US4026786 Perforated Ti uncoated substrate for PbO2 from HNO3 100 g. per liter Pb(NO3)2 bath.pdf (121kB)
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[*] posted on 22-6-2007 at 20:37


Thats a really interesting patent. Perhaps the ceramic particles they mention could be made from magnetite?



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[*] posted on 22-6-2007 at 23:00


I'm not sure what the ceramic is , but it is probably something that has near neutral buoyancy in the electrolyte so it stays suspended and scours the surface lightly like a polishing compound does in a rock tumbler . Any inert material of the right density and mesh size would probably work . Having a good flow velocity for the electrolyte should tear any bubbles away pretty fast . Adding some vibration to a scheme having microspheres , the impacts could have a peening and burnishing effect which would tend to close off any pores and shift around the nucleation sites for new bubble formation so that an evenly coated surface results even for very thin layers . The throwing power is probably great enough that this *extra* technique is probably not absolutely necessary but is only an enhancement .

I have been looking for information on the possibility of using
a PbO2 overplating of a Co3O4 doped MnO2 intermediate layer on a titanium substrate , and also looking at the possibility of loading magnetite into a Co3O4 doped MnO2
intermediate layer . There is a perchlorate cell tested variant
using a doped MnO2 anode having titanium substrate described in US4072586 . Evidently a bit of Co(NO3)2 added
to Mn(NO3)2 increases the conductivity and life of the anode .
An addition of 10% of the carbonates to the nitrates and
baking out at 300C for 5 minutes is optimum . ( US3553087) After the first three coats are baked , a thickener can be added (hydroxyethylcellulose) to get a heavier build on subsequent coats . (US4243503) Additionally Sb or Bi dopants to the finish layers of MnO2 have a catalytic effect on perchlorate production .

Further , a titanium alloy having 1.5% cobalt is better than pure titanium for a substrate , and so is a 1.5% manganese alloy . I have no idea what is the composition of various commercial grades of titanium alloys , but it may well be that
certain existing alloys could be better suited for substrates
than the pure material .

BTW , on page 8 of this thread I posted another patent which
related to a bismuth doped PbO2 having increased conductivity and improved wear resistance , and in the plating bath containing a small quantity of bismuth nitrate
it was found necessary to use a higher HNO3 content plating bath ....and amounts even up to 150 g / liter were charted ,
but this would seem excessive . Anyway the same fine grain deposits were reported for the bismuth doped PbO2 anodes
gotten from a highly acidic bath , although they were brittle and cracked when thick layers were attempted .

Attachment: US4101390 Bismuth modified thin layer Lead Dioxide Perchlorate Anode.pdf (977.42 KiB)
http://www.sciencemadness.org/talk/viewthread.php?action=att...

[Edited on 23-6-2007 by Rosco Bodine]

Attachment: US4072586 Baked Mn(NO3)2 Manganese_dioxide_electrodes.pdf (156kB)
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[*] posted on 23-6-2007 at 15:23


Hello Rosco,

My, you ARE going to be busy! There is enough material and possibilities here to keep a team of scientists going 24/7 for the next six months :D
Patent 4,026,786 does not mention making Chlorate or Perchlorate for the anodes, if that makes any difference. Only electro-winning metals.
It is a bit like US 3,634,216. This is also a high nitric acid bath but the Lead Dioxide is being produced for production of powdered Lead Dioxide only.

Cheers,
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biggrin.gif posted on 23-6-2007 at 18:42
cobalt oxide anode


Quote:
Originally posted by dann2
Hello Rosco,

My, you ARE going to be busy! There is enough material and possibilities here to keep a team of scientists going 24/7 for the next six months :D

Just glean what information is useful and put it together in one system .
Quote:

Patent 4,026,786 does not mention making Chlorate or Perchlorate for the anodes, if that makes any difference. Only electro-winning metals.

The bismuth doped PbO2 patent US4101390 is analogous to US4026786 , and it is for a perchlorate anode .
Quote:

It is a bit like US 3,634,216. This is also a high nitric acid bath but the Lead Dioxide is being produced for production of powdered Lead Dioxide only.
Cheers,
Dann2


5-20 g HNO3 per liter for US3634216 is a lot lower acidity than the 100 - 120 g HNO3 per liter of US4026786 which relates nicely with the even slightly stronger 150 g. HNO3 per liter for the Bismuth doped PbO2 of US4101390 . Bismuth is a catalytic dopant for MnO2 anodes destined for perchlorate production , as is antimony ....and evidently this is also true for PbO2 anodes .

Finer grained and more conductive platings produced
under less pH sensitive conditions is something that
is worth consideration for a one tank setup where
a relatively thin layer is going to be deposited .

When it comes to the oxide plating ,
there is actually an electrodeposited cobalt oxide which is supposedly superior to PbO2 in conductivity and resistance to erosion . This might also be used as an intermediate layer .

[Edited on 23-6-2007 by Rosco Bodine]

Attachment: US3399966 Substoichiometric Cobaltic Oxide Electrodeposited Anode.pdf (180kB)
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[*] posted on 24-6-2007 at 04:29
Patent# US3399966


That's a great patent!

If we can take that information at face value (and I realize that's a big "if"), that may be a big advancement.

Seems you can easily apply the oxide electrolytically over almost anything, including Ti and graphite, with no other substances (e.g., dopants), and no other treatments (e.g., baking), required.

Moreover, on page 4, the inventors state:

"The anode of deposited CoO is not perfectly insoluble in a solution with pH under 1 containing bromide, iodide, or other anions haviing discharge potential of under +0.7v.; however it is perfectly insoluble in the solutions of pH above 1 containing chloride, sulfate, nitrate or the like. Then it is most effective for the electrolysis of sodium chloride, chlorate or the like."

So apparently it will make chlorate and perchlorate! Sounds like it would be definately worth a try. Now, where's the cheapest place to get cobalt salts?
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biggrin.gif posted on 24-6-2007 at 08:31
Dipped and Baked Cobalt Oxides works too


Quote:
Originally posted by jpsmith123
That's a great patent!


Yeah , and another interesting aspect is the possibilities for any of the conductive oxides which may be applied by either
electrodeposition or by the relatively low temperature decomposition of a salt . I am not sure what might result if
the techniques of electrodeposition and thermal decomposition to the oxide were sequenced , but there
is the possibility for interesting results . I have thought about the enamelware pots and pans where a low melting
ceramic is applied as a "powder coat" which then fuses on baking , possibly reacts as some refractory materials do to
form a thermosetting material ....and if this same idea can be exploited for a semiconductive oxides coating , then there
could be some interesting modified spinel type of glasses or
ceramics for anodes , which possibly could be applied to just about any conductive substrate .....or possibly even sintered into a solid stick of conductive ceramic .
Quote:

If we can take that information at face value (and I realize that's a big "if"), that may be a big advancement.

See US6001225 for a similar cobalt oxide which may be formed from the same cobalt nitrate solution simply by a baking of the dipped substrate . A Diamond Shamrock patent US4243503 , Ex.#8 describes 80 g. of the hexahydrate of cobalt nitrate plus 20 ml of H2O as a dip and bake at 350C for 15 minutes produces the cobalt spinel Co3O4 , also useful as an anode coating . Natrosol thickening agent can also be used on these coatings to give a heavier buildup , and the cellulose soluble fiber burns out on baking , the same way as it does when used in ceramics glazes . Duh dip dip dip :D
Quote:

Seems you can easily apply the oxide electrolytically over almost anything, including Ti and graphite, with no other substances (e.g., dopants), and no other treatments (e.g., baking), required.

Moreover, on page 4, the inventors state:

"The anode of deposited CoO is not perfectly insoluble in a solution with pH under 1 containing bromide, iodide, or other anions haviing discharge potential of under +0.7v.; however it is perfectly insoluble in the solutions of pH above 1 containing chloride, sulfate, nitrate or the like. Then it is most effective for the electrolysis of sodium chloride, chlorate or the like."

So apparently it will make chlorate and perchlorate! Sounds like it would be definately worth a try. Now, where's the cheapest place to get cobalt salts?


Sheesh I don't know . With the price of nickel having gone up so much recently ...and cobalt being a byproduct of nickel refining ...I wonder if cobalt has gotten expensive also .

And yeah the coating should be , probably is , versatile on many different substrates , and is both a semiconductor *and* a catalytic material . The effect with MnO2 is probably similar as to what occurs with Bi and PbO2 . A coating having catalytic properties on top of good low resistance semiconductivity and chemical erosion resistance specific to the intended use is three wins . I wonder if Cobalt has usefulness as a dopant for Tin or Bismuth ? There are probably a lot of references concerning the cobalt containing spinels and cobalt containing catalysts . I haven't yet searched the literature to see what is there . Mostly what
I ever thought about with regards to cobalt is the pink to blue color change used for a hydration indicator on drierite ,
and as a minor alloying metal in some steels . Looks like it is good for a few other things as well :D

[Edited on 24-6-2007 by Rosco Bodine]
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[*] posted on 24-6-2007 at 08:55


Cobalt is the binder metal in tungsten carbide materials, up to 20% in some, but more typically 3-5%. Thin carbide slitting knives used in cardboard and plastic sheeting manufacture are +10% cobalt.

With nickel going for over $22/lb, I wouldn't be surprised if cobalt salts are more than $100/lb. You can get some from pottery suppliers, as it is the pigment responsible for Wedgewood Blue.

There is a patented conductive Titanium suboxide ceramic anode material marketed as Ebonex.
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[*] posted on 24-6-2007 at 09:56


Looks like cobalt carbonate is not too expensive ,
about $26.50 / lb
http://store.ceramicstoreinc.com/cocacooxcoca.html

Quote:
Originally posted by Eclectic
There is a patented conductive Titanium suboxide ceramic anode material marketed as Ebonex.


Back on page 13 of this thread I had actually mentioned Ebonex , ( I just removed the quotation marks which prevented a search from returning hits on it )
Ebonex has actually been investigated for usefulness
as a perchlorate anode , but the one report I found in the literature did not give it a favorable result for that application as a substrate when coated with PbO2 , its efficiency was low . Perhaps some other coating , like cobalt or manganese oxides would fare better . Evidently perchlorate cells are pretty specific in what combinations of materials work well for anode construction and coatings and there are only a few combinations that work okay while most fail for one or more reasons .

One curious thing is the profound catalytic activity of bismuth even at microscopic trace levels as a dopant for PbO2 in perchlorate production . Reportedly simply dipping a PbO2 anode into a bismuth nitrate solution leaves enough residual bismuth on the surface to produce a significant lowering of the cell voltage for perchlorate production by that anode when it is put into a perchlorate cell ...several tenths of a volt difference IIRC and tens of percentile increases in cell efficiency ....simply from trace levels of bismuth on the PbO2 .
So clearly , catalytic dopants do matter and can be key actually in whether a particular anode works beautifully or not well at all .

[Edited on 24-6-2007 by Rosco Bodine]
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Eclectic
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[*] posted on 24-6-2007 at 11:36
Solder Chloride Solution


I just dissolved the remaining 325 gr. of my 95/5 solder in 800 ml 31.5 HCl on a heading bath overnight, with 400 ml HCL added this morning. Evaporated for a while and decanted from the insoluble residue, I got 250ml of water white solution I'm assuming is fairly pure SnCl2. I was able to dissolve the insoluble residue in my previously made bright yellow SnCl4/SbCl3 solution with the addition of about 25ml 30% H2O2 in 50 ml 31.4% HCl. The yellow compound decolorized until the last bit of peroxide was added. I suspect it's SbOCl3, which shouldn't cause any problems, but if it bothers you you can heat the solution with a few snippets of tin to decolorize it. So now I have ready to go Sn/Sb oxide coating solution with 15-20% Sb, all from OTC materials. I can add some of the SnCl2 solution to reduce the Sb concentration if needed, otherwize I'll use it as a tinning compound for circuit board work and soldering.

Rosco, I like the bismuth dopant for a PbO2 overplate, also the alpha, beta PbO2 layering to reduce plating stresses. With an inert conductive substrate and good adhesion, this should work VERY well. :D

[Edited on 6-24-2007 by Eclectic]
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[*] posted on 24-6-2007 at 12:13


Hello,
Cobalt Sulphate (Cobaltous Sulphate, Cobalt II Sulphate) can be purchased down at the local farm store as a trace element supply for sheep (!!). Sheep run low in Cobalt in certain areas. (I'm not joking).
It is about 40 dollars per KG.
With Calcium Nitrate you can make Cobalt Nitrate my dissolving and letting Ca Sulphate ppt.

Dann2
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[*] posted on 24-6-2007 at 14:07


Hello Dann2,

Example 2 of the patent uses the sulfate. And in the claims part of the patent, they mention nitrate, sulfate, acetate and fluborate. So it looks like you wouldn't have to bother converting to nitrate.
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[*] posted on 24-6-2007 at 18:31


Hello JP,

This anode making just gets easier and easier!
I used to think that Cobalt Sulphate and Cobaltous Sulphate were different compounds. Not so.
It would (as others have said here) be great to get away from Lead Compounds altogether.

I tested the product from my Magnetite coated with Lead Dioxide anode cell today and it is Perchlorate (as expected). Since the coating of PbO2 was so thin on the Magnetite it is hard to tell if it is still there or not. Both substances are black and that makes it harder to see the Lead Dioxide. After cleaning the anode there still seems to be a difference in texture where I put on the LD.
I intend to properly coat a piece of Magnetite tomorrow and run a Chlorate cell taking note of amounts of product, current, etc, etc.

I coated the top end of Magnetite with Copper. Silver does not seem to suit Magnetite. Copper is best.
I used a 'standard' Copper bath for plating Copper. 78 grams Copper Sulphate:7H2O, 18.5 grams Sulphuric acid, 500 grams water. 32C, Anode is pure Copper. Current density about 60mA per square cm. Good Copper coat after about half hour.


Dann2
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