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Rosco Bodine
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@jpsmith123
I think this was the one caught my notice
http://dx.doi.org/10.1016/j.electacta.2007.06.066
Here's other ones you might like too
http://dx.doi.org/10.1016/j.jpowsour.2007.01.072
http://dx.doi.org/10.1016/S0022-0728(02)00642-3
[Edited on 9-12-2007 by Rosco Bodine]
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Xenoid
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I just went down to check on my remaining Co - nitrate concentrate which I had left in the fridge, at about 0 oC. It has crystallised nicely after
about 3 or 4 days, leaving about 40 mls of supernatant liquid (containing impurities... ) which could be poured off, and the crystals drained. They really are a pleasing colour! And not so difficult to crystallise after all.
Image shows cobalt nitrate hexahydrate crystals in the bottom of the SS evaporating saucepan. Diameter of crystal mass is ~ 13cm, depth is about 4mm.
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jpsmith123
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Xenoid if you have some Co Sulfate left and some boric acid, you could try that cathodic electrodeposition formula. Who knows, it may work like they
claim it does!
I'm going to order some Co(NO3)2 tomorrow, but it will likely be a week to ten days before I have it.
As far as the microwave oven thing goes, I think I will try it. Unfortunately my cheapo "Chefmate" 0.7 ft^3, 700 Watt piece-of-junk from Target just
died about one week ago (after only 3 months of light use). The next Christmas-sale sub $40 oven I see, I will buy, just for purposes of testing this
idea.
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Rosco Bodine
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This is pure speculation , but an idea which
just might work .
Instead of the bronzing filler made from
TiH2 plus Co(NO3)2 , I have an idea for a possible
alternative material which would be more OTC
and perhaps would work nearly as well .
http://www.sciencemadness.org/talk/viewthread.php?goto=lastp...
The residue from ignition of the cobalt doped fuel and active alumina precursor , could be further digested with cobalt nitrate in acetone or alcohol
, painted onto the anode having the initial cobalt spinel interface and baked .
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Twospoons
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@jpsmith : hold on to that dead microwave - it is bound to have a good transformer in it. If you have a variac, you could make a variable power
microwave - use the spare tranny for magnetron heater supply, then run the bias on a second tranny powered from the variac. Then you should have much
better heat control.
Dammit, I had a link to a page where a guy used this trick to power an e-beam melter in a vacuum deposition chamber - there was a lovely schematic.
Helicopter: "helico" -> spiral, "pter" -> with wings
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dann2
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Hello,
Hope to get on the Co Oxide bandwagon tomorrow. It will make a change from the DTO/LD bandwagon.
What impurities are likely to be in Ceramic store variety Cobalt Carbonate and Zr Oxide.
Will Zr Oxide dissolve in Nitric acid to give Nitrate?
DOT Anode still going strong. Approx. 180 hours.
I am going to start up a Lithium Chlorate (or is it Perchlorate) cell using Li Chloride (made from Lithium Carbonate + HCl) and the DTO anode.
Current denisty on anode will be 200 mA per square cm much more that of now.
Lithium Perchlorate forms easily and in great abundance you know!!!!!!!!
Dann2
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not_important
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Pottery grade cobalt compounds should be pretty clean. As it is used to color ceramics other elements that have their own colour effects would
interfere.
ZrO2 doesn't dissolve in anything short of HF. The usual way of getting it into solution is fusion with Na2CO3, leaching and washing of that with
water, adding the insoluble portion to concentrated H2SO4 and heating to the fuming stage; on cooling a zirconium sulfate that will dissolve in water
is obtained. However the anhydrous sulfate slowly converts to low solubility hydrated forms, so it is best after dissolving it to soon add it to cold
aqueous ammonia to precipitate the hydrated hydroxide, which will react with and dissolve in acids.
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Xenoid
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Quote: | Originally posted by dann2
I am going to start up a Lithium Chlorate (or is it Perchlorate) cell using Li Chloride (made from Lithium Carbonate + HCl) and the DTO anode.
Current denisty on anode will be 200 mA per square cm much more that of now.
Lithium Perchlorate forms easily and in great abundance you know!!!!!!!!
Dann2 |
@ Dann2
Sorry Dann2 I beat you to it, been there, done that, with gouging rods!
I started a Li (per)chlorate cell back on the 27th Nov. It's been running for over 13 days now. I made the LiCl via a fairly stoichiometric conversion
of the carbonate with HCl. I ended up with ~250g of LiCl in 800mls H2O after filtering. I boiled this down to 600 mls and used 400 mls in the cell ( ~
160g LiCl).
The cell is a funny little design, with 4 half-length gouging rods, and a central SS sheet for a cathode. The cell is shown below just after start up.
It's running at about 3.5 volts and 3 amps and the electrical parameters haven't changed since I started it. I haven't been paying much attention to
it, what with all the Cobalt excitement, other than adding water. I was planning on running it until the gouging rods disintegrated to see if any
perchlorate was made. It should happen soon!
Because of the "light weight" of Li adding 3 or 4 oxygens makes a big difference to the weight. I did a rough calculation, based on starting with 100g
of Li2CO3 assuming 100% conversions you will get 115g of LiCl, 245g of LiClO3 and 288g of LiClO4 which will convert to 375g KClO4.
I'm not entirely sure what I'm going to do with this cell when it finishes, it seems to be pretty inefficient, when I started it, I had magnetic
stirring, but it kept spinning out so I gave up on it!
[Edited on 10-12-2007 by Xenoid]
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Xenoid
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WARNING NOTE:
Just a short note to anyone doing any Ti etching using hot / boiling conc. HCl.
I've just been doing a bit of tidying up, etc in my garage/workshop/lab and I've noticed all my tools are rustier than normal.
I hadn't thought that the HCl fumes were all that bad, given where I was doing the etching, but obviously it's quite insidious, I should have known
better (given that I have spent most of my life involved in operations using boiling HCl [in a fume hood, I might mention]).
Make sure you do this operation outside or in a fume hood if you have one!
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dann2
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Hello,
Tidy cell, not able to see the humurous side of it, but never mind.
I presume the picture of the Cell was taken just after you made it. (No black mess)!!!
The patent states that current density should be between 150 and 250mA per square cm. Perhaps it is not important. The patent used Pt as the anode
anyways so it probably does not apply to C or DTO or whatever we are using.
The most colourful version of the patent on the net is here:
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
I will be an extremly angry and bitter little man for a month or so since I was beaten to it, but that's life.
Will be using DTO so perhaps it may be interesting. Was going to use graphite (thankfully I did not) but the DTO was to hand and handier.
I guess the Zr Nitrate project is not as simply as I had speculated. ![:(](./images/smilies/sad.gif)
Dann2
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Xenoid
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Quote: | Originally posted by dann2
I will be an extremly angry and bitter little man for a month or so since I was beaten to it, but that's life.
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Yeah... sorry to drop that one on you Dann2. No one said they were doing it, so I went ahead.
I guess the cell is "funny" queer not "funny" humorous! It's just a bit different to my normal design, when I finished it, I found the damn lid kept
popping out so I had to tie it on with the plastic straps!
I was going to start a Li (per)chlorate thread but never got around to it, because of the Cobalt.
I haven't done much lately, I've been recycling some cobalt nitrate and sulphate solutions (too expensive to throw away). Also making some more
manganese nitrate (..ugh) when I try to concentrate it, it decomposes and starts to turn brown, I've stabilised it with HNO3 and will concentrate
further, hopefully get some crystals!
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Xenoid
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Quote: | Originally posted by Rosco Bodine
That's a good setup , but you could drill a 1/16" hole through the rod very close to the top and then put a wire
through the hole and bend it aound and back to itself to make suspension loop , hanging the rod like a wind chime
inside the furnace tube . |
@ Rosco, I didn't know what I was talking about, I had previously drilled 1mm Ti sheet with an ordinary HSS drill, but assumed it wouldn't go through
10mm, because of what other people were saying in other threads. Well I have just drilled two 3mm holes using a good quality HSS drill and there was
no problem at all.
I'm going to adopt your idea and hang the anodes by a fine copper wire loop from the top, my fairly heavy 9.5mm anodes are quite stable, lighter
anodes may blow around though!
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Rosco Bodine
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My windchime idea is probably going to bang around
from the airflow if you hang it from one wire and it
isn't stiff enough . Probably better to bend a loop
eyelet in the end of some stiff wire , use one on each side
and put a screw through it , or use some stainless
or solid copper twist tie wire on each side . That should be rigid enough not to swing around . Could use the same fixture as a holder when you are
coating it , etching , ect .
With a 3 mm hole you could wrap a flat ribbon of braided fiberglass tube like they use for bundling wiring harnesses
around the rod end and stick it inside a large enough tubing to be a snug fit , having a 3 mm hole to match bored in the larger tube , and stick a
cotter key or put
a screw through the assembly . That would be rigid
and it would be thermal breaked enough it wouldn't
heatsink that short covered end of the rod so much .
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dann2
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Hello,
The dreaded HCl will indeed corrode everying around (as will a (Per)Chlorate mist). I have gone through about one gallon of 12% HCl keeping my
'etching pot' topped up.
It would be nice and quick to have HF and Nitric acid as below. The Ti needs only about 15 seconds to etch.
No heating or fumes (I presume?). Would be dangerous stuff though. I think you can purchase the HF from shops that do glass etching (fancy windows).
From US 4142005
The etching solution used in some of the examples below was prepared by mixing 25 ml analytical reagent hydrofluoric acid (48% HF by wt), 175
ml analytical reagent nitric acid (approximately 70% NHO.sub.3 by wt), and 300 ml deionized H.sub.2 O.
also from above pat:
(regarding the large final bake)
In the following examples, the "brushing" following the dipping operation is done to avoid "runs" and to assure a smooth uniform coating. An
extended heating period of the final coat anneals and densifies the coating.
About to start some Cobalt baking via above patent. It takes quite a time to get Co Carbonate to fully react with Nitric acid. It's the last little
bit (as the acid solution gets neutral) that takes all the time.
Dann2
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You actually want to have a little excess carbonate, even adding a few percent excess at the end. Add a little H2O2 and boil gently for a few
minutes, let it cool, and filter. Iron and manganese stay behind with the excess carbonate, as do some other metals if present in only small amounts.
This is a standard method of preparing decent purity salts from sources of unknown purity.
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Xenoid
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Hi guys,
Here's my latest Co oxide (spinel) anode, it's smoooooth, shiny and HARD.
Despite what I said in various previous posts I decided I had to go the full way and see what 12 coats looked like - they look good! It took most of
the afternoon but I think it was worth it!
I used a 50% cobalt nitrate hexahydrate solution.
A few minor differences from the previous anodes;
1) The anode was hydrided after etching.
2) The anode was hung from the top of the heat gun tube, this is less clumsy and gives better access than my previous arrangement. I think the heat
distribution is probably a little more even as well.
3) I gave the anode a bit of a wipe (almost a polish) with a soft cotton cloth, between coats, to remove loose dust. My feeling about this was that it
would help to make the coating more compact.
4) To speed things up, I did a few minutes cooling in the fridge, and then when still warm to the touch, did the dipping!
I did a quick check to see that it was working by putting it in a perchlorate cell. I set the current density to 50mA/cm^2 voltage was quite low, 3.7
volts, bubbles and ozone.
I'm open to suggestions as to what to do with this anode (NOTHING RUDE PLEASE). I would like to put it back in a perchlorate cell, as, quite frankly,
I think chlorate cells are a "piece of piss" for these anodes or will eventually prove to be so!... ![:P](./images/smilies/tongue.gif)
If anyone has any suggestions for a simple baked on doped overcoat I will try it, otherwise I'll just put it in "as is" and run it to
destruction..![:o](./images/smilies/shocked.gif)
The other 4 coat anode in the chlorate cell is still running fine, the coat is wholly intact, but is possibly starting to thin in places (like my
hair). There seem to be a few more bits of black floating around. It's been going for 4 days and 6 hours now.
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Xenoid
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Quote: | Originally posted by dann2
have gone through about one gallon of 12% HCl keeping my 'etching pot' topped up.
It would be nice and quick to have HF and Nitric acid as below. The Ti needs only about 15 seconds to etch.
From US 4142005
The etching solution used in some of the examples below was prepared by mixing 25 ml analytical reagent hydrofluoric acid (48% HF by wt), 175
ml analytical reagent nitric acid (approximately 70% NHO.sub.3 by wt), and 300 ml deionized H.sub.2 O.
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Dann2 - there are products in engineering and welding supplies shops, called pickling pastes and liquids. They are used to remove black oxide stains
and build-up after welding of stainless steel. They leave a satin like etched surface. I have noticed them before, because they contain mainly HNO3
and HF. Here's an example of such a product from here in NZ, it's called "Chromebright";
https://pgw100.portal.gases.boc.com/boc_sp/nz/safety/0177.pd...
I'll pick some up when I'm in town next, and give it a try. It will take longer than 15 secs., but if it works in 1 or 2 minutes that would be quite
good! If it's a paste, one could have it in a tall plastic container and just poke the rod down into it. If one is using Ti sheet or mesh it can be
painted on!
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Rosco Bodine
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If you have some copper nitrate and/or some nickel nitrate
you might test the alternating layer scheme where a different Co bimetal spinel , with copper or nickel , is applied over the first coat of monometal
Co spinel ,
then another "buffer layer" of monometal Co spinel ,
then another layer of Co bimetal spinel ...and so on .
This would be pure experimentation to see if indeed
the predicted diffusion would occur between subsequent
layers of differing chemistry spinels which would chemically
react to possibly better fuse each layer with the next ,
hopefully reducing the porosity and increasing the density
of the sequenced coatings , and possibly effecting a
bi-electrode benefit to the outer coating as well .
If there's one simplest and logical spinel related experiment to do , this would seem to be it . These Co bimetal spinels
are reportedly tougher and more conductive than the monometal spinel , especially the cobalt nickel bimetal spinel .
But this is a generalization , and I have no data on this specific to perchlorate production efficency .
I'll check the ratios of Co(NO3)2 to the Cu and Ni nitrates
to be sure , but IIRC it was 2:1 for the mix . Zn is another one reported to give good results . I would hold the maximum amount of the substituent
to perhaps 10%
less than the exact 2:1 , so there is a little excess of the
Co monometal spinel , going with a ratio of 2 : 0.9 for example instead of approaching closer to the theoretical .
Having excess of the simple second oxide not transformed into the bimetal spinel could be counterproductive , but having less than the theoretical
complete reaction could still largely have the benefit expected for the diffusion layer between the differing composition spinels .
HF is a good material to avoid if possible .
[Edited on 11-12-2007 by Rosco Bodine]
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jpsmith123
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Quote: |
If anyone has any suggestions for a simple baked on doped overcoat I will try it, otherwise I'll just put it in "as is" and run it to
destruction..![:o](./images/smilies/shocked.gif)
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I would suggest adding some TiO2 powder into your Co Nitrate. Being that we're experimenting, why not give it a try one time?
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jpsmith123
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Conclusions from the Mn-Co Oxide Coatings Power Point presentation
- The chemistry and morphology of coatings can be
manipulated by adjusting deposition parameters.
- As-deposited Mn-Co oxide nanocrystals have a metastable
rocksalt-type structure.
- Rocksalt-to-spinel phase transformation is induced at
temperatures higher than 500°C.
- Mn-Co-O coatings can improve the oxidation resistance of
stainless steel substrates.
- During annealing at 800°C, Cr and Fe diffuse into the Mn-
Co-O coating.
####################################
Their electrodeposition bath contained CoSO4, MnSO4 and 0.2M disodium EDTA.
Temp= 25-90 degrees C; I= 5-50mA/cm2; pH= 6.0
See attached related paper.
[Edited on by jpsmith123]
Attachment: Paper.pdf (358kB) This file has been downloaded 1022 times
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dann2
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Hello.
Good Anode, I have kept the picture for my ambum (if you don't mind)!
When you say that a Chlorate cell is a 'piece of piss', do you mean that the anode will make Chlorate easily or will easily stand up to the Chlorate
cell (or both).
I am inclined to think that a Perchlorate cell is not any more corrosive to anodes (except Graphite) that an Chlorate cell . I fact a Chlorate cell is
harder on Lead Dioxide but perhaps I am talking through my hat, guessing really. In industry ALL Chlorate cells are pH controlled and this (I think)
makes them less corrosive generally. Your Chlorate cell will not be pH controlled. Of course if an anode does not make Perchlorate then there is
little point in worrying if it corrodes or not in a perchlorate cell.
Will Cobalt Oxide make Perchlorate? I reported some time back that it did but then later when I discovered that my plated-on Co Oxide coat had worn
off, I was not 100% sure if it was the Co Oxide or the exposed DTO that made the Perchlroate.
Go with a Perchlorate cell and see will it make Perchlorate at a reasonable effeciency.
Of course if you are looking for a good solid overcoat, you could try a good thick coat of a substance with a formula
of..................................PbO<SUB>2</SUB>. ![:P](./images/smilies/tongue.gif)
You could also try a Chlorate cell and try to go all the way to a low concentration of Chlorate (to end of Perchlorate cell) to see has Cobalt Oxide
'HOLY GRAIL' status. ![:D](./images/smilies/biggrin.gif)
Still drying my Co Nitrate crystals to weigh them.
The paste is a good idea. Seen it too. Will try. No fumes, no heating, fast, OTC, ....QED.
Dann2
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Xenoid
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Quote: | Originally posted by dann2
When you say that a Chlorate cell is a 'piece of piss', do you mean that the anode will make Chlorate easily or will easily stand up to the Chlorate
cell (or both).
Still drying my Co Nitrate crystals to weigh them.
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"piece of piss" - Australian / New Zealand saying, it means "easy"
@ Dann2 - Well I think my first attempt, 4 coat anode is lasting very well in a chlorate cell. I think that with a full coating, doping, different
layers and treatments it will not be too difficult to make an anode that goes full distance in a chlorate cell or lasts for 2 or 3 cells.
On the other hand, the Co oxide anode only lasted 14 hours in a perchlorate cell, and even then I'm not sure it was producing perchlorate efficiently.
So I think more experimentation is needed with the perchlorate aspect, I'm sure we can sort out any problems with the chlorate... ![;)](./images/smilies/wink.gif)
BTW - I wouldn't worry about trying to dry the cobalt nitrate, I just used moist, drained crystals, with an equal weight of water. I don't think the
concentration of the dipping solution is all "that" critical!
[Edited on 11-12-2007 by Xenoid]
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Xenoid
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Chlorinator Disassembly
Well, I decided to have a go at disassembling the chlorinator top! The blue plastic cover came off fairly easily, with a bit of cutting, exposing the
epoxy potting medium. This stuff is tough and brittle at the same time. It cuts with a hacksaw, but when you hit it with a hammer and chisel it splits
with a conchoidal fracture and flies in your face. I guess it's like the epoxy dentists use for fillings. I've managed to get about a third of the way
through it and expose the bent over tops of two electrodes. I've also been able to remove a 12mm x 100mm Ti strip that was being used as a support and
some sort of earth/guard electrode. In the image it is shown lying across the top of the assembly. It will be useful as a test electrode for coatings.
I think I can get this all apart, eventually!
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chloric1
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Quote: |
On the other hand, the Co oxide anode only lasted 14 hours in a perchlorate cell, and even then I'm not sure it was producing perchlorate efficiently.
So I think more experimentation is needed with the perchlorate aspect, I'm sure we can sort out any problems with the chlorate... ![;)](./images/smilies/wink.gif)
[Edited on 11-12-2007 by Xenoid] |
When you say that the anode only lasted 14 hours in the perchlorate cell, are you talking about the one with only 4 coats. I think that is what you
said but I want to eliminate any doubt. Rosco's suggestion seems worthwhile if anything then after that then there is plating the cobalt anode with
PbO2.
Fellow molecular manipulator
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Xenoid
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Quote: | Originally posted by chloric1
When you say that the anode only lasted 14 hours in the perchlorate cell, are you talking about the one with only 4 coats. I think that is what you
said but I want to eliminate any doubt. Rosco's suggestion seems worthwhile if anything then after that then there is plating the cobalt anode with
PbO2. |
It was my third anode, the one with 8 coats (but the dipping solution was only 25%). I guess the coat thickness should have been the same as the 4
coat anode (50% dipping solution). It basically just wore away, it didn't flake off.
I'm wondering how the wear rate relates to coating thickness and whether it's linear or not (hopefully not). If it's linear and a four coat anode
lasts for 4 days, then a six coat anode will last 6 days etc. etc. Hopefully it's more like 4 for 4, 6 for 8, 8 for 16, 10 for 32 or possibly much,
much, better than this. It's just going to be matter of testing and more testing.
I'm inclined to put my latest 12 coat anode in a perchlorate cell and just let it run, this way we can get some good basic information about optimum
numbers of coats and the way they build up wear resistance - is it a linear or perhaps an exponential process! I think it's best to do this "basic
research" first on the "plain" Co oxide, before trying more exotic procedures. The more contributing, the faster this will get done! If we don't have
this initial basic research it's going to be hard to make comparisons between different procedures.
If everyone who is having a go at this could stick to a 50% Co nitrate solution and bake at 370 oC. we can soon build up some baseline information on
the longevity or otherwise of simple Co oxide coatings. If some could try 6, 8 or 10 coats in both chlorate and perchlorate. We can then plot some
curves to which we can compare "modified procedures" - and there is literally no end of them.... ![:D](./images/smilies/biggrin.gif)
[Edited on 11-12-2007 by Xenoid]
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