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Author: Subject: More on PbO2 electrodes
Rosco Bodine
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[*] posted on 5-6-2007 at 00:12


Quote:
Originally posted by hashashan
Never mind, one of my friends told me that, usually he does know what he's talking about.
But if you say that it doesnt really matter ill try to take about 1cm distance with 5V(damn there's going to be a high current)



Since you can't adjust the voltage , then you have no choice but to adjust the spacing , and dump any excess
power as heat . You might try the 3.3 volt output for
close spacing . Also you need to hit your target current
based on the area of your anode . So having only fixed
voltages you will have to try different combinations to
find what is most power efficient .

This is where having a laboratory power supply would
make things much better , as you could choose whatever
spacing you want to use , and then just dial in the voltage
which brings the current up to where you want it .

But not having that control , you will have to make the adjustments differently in a less convenient way .

[Edited on 5-6-2007 by Rosco Bodine]
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dann2
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[*] posted on 5-6-2007 at 15:35


Quote:
Originally posted by hashashan
Never mind, one of my friends told me that, usually he does know what he's talking about.
But if you say that it doesnt really matter ill try to take about 1cm distance with 5V(damn there's going to be a high current)


Hello,

I am using a computer power supply to power my experimental cells. I can get any current I want (below max. for supply of course) by using an electronic device, a diagram
of which if which is below:

____________________

Diagram above ;)
It is a piece of Nicrome wire. Get a piece from a old electirc fire/heater. Tap the wire where you are getting a current that suits you. If the wire/resistor is too short at the current you
want just use two lengths of the wire (or three or four) in parallel and you can use a longer piece. The wire will get (very) hot but that is not a probem.

Dann2
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Rosco Bodine
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[*] posted on 7-6-2007 at 00:08
some new finds


Here is a strange one . Reportedly if lead is in contact
with certain other materials , like particles of magnetite for
example , the lead exhibits a self-healing quality under anodic conditions which penetrate an adherent PbO2
coating .....so the exposed metallic lead reforms a protective layer of PbO2 and does not corrode !

Attachment: US3454472 Sintered Lead and Magnetite PbO2 Anode Substrate.pdf (186kB)
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Rosco Bodine
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[*] posted on 7-6-2007 at 00:17
another conductive ceramic anode


Here's a different conductive ceramic patent .

BTW , in yet another patent I was reading that there is
a glass formed that is a binary eutectic PbO:V2O5 mp 480C
which has fluxing properties towards other metallic oxides .
I have no idea what may be its electrical properties .

This might have interesting possibilities as a binder
for PbO2 or other conductive oxides , or some mixture
which might form a conductive glass , and have a reasonably low melting point .

Attachment: US3372107 Ceramic anode for perchlorate.pdf (95kB)
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Rosco Bodine
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wink.gif posted on 7-6-2007 at 10:08
Brainstorming ! Any help available ????


In an earlier post I mentioned an idea for a sacrificial lead metal plate to be used in simultaneous fashion within the
PbO2 plating cell , as a means of keeping the Pb content
and the pH constant .....and I am still thinking about this
as the ideal way of keeping the plating bath composition
constant , if it is workable . I had thought of using an amalgamated lead plate as a sort of
" neutrode " as I termed it , a passive lead source which would simply be
vulnerable to corrosion and dissolution by increasing acidity of the bath .

Anyway , I have been thinking more about this and the idea has evolved to consideration of making the consumable lead
part of the same circuit as is used for plating the PbO2 ,
making the consumable lead plate an electrolytically driven
" auxilliary anode " which would be solubilized to replenish
the Pb content of the bath , at precisely the same rate as
is Pb being plated out as PbO2 .....so that the Pb content
of the plating bath and also the pH , is held constant .

This might require the use of two separate cells with the
common electrolyte circulated continuously in a loop supplying both cells ....but likewise having the two cells
electrode pairs form an electrical series circuit so that
the same current flows through each . In that way ,
the same amount of Pb plated out as PbO2 would be
precisely replaced , and at exactly the same rate .
In this manner the process would self-regulate the
composition of the electrolyte . At the end of the plating
of PbO2 , even after days of operation at whatever variations
of current or temperature within reasonable limits .....the composition of the plating bath would remain exactly where
it started in regards to pH and Pb content . :D

So what do you guys think ? And do you have any suggestions or ideas how this should or should not work ?

For reference purposes , there is a patent US459946 which I attached in the lead salts preparation thread .
The arrangement which I am contemplating for the series
circuit would be to use a power supply negative output lead
to a stainless or graphite cathode in the PbO2 plating tank ,
and placed nearby will be the anode substrate onto which the PbO2 will be plated . An electrical cable connection is made to the substrate and the opposite end of the cable is connected to a cathode plate of graphite or stainless in a second tank (if necessary to be separate ) . Spaced nearby this cathode in the second tank is a lead sheet anode having electrical connection to the positive output of the power supply so that the two cells operate in series . Of course a higher voltage will be required to drive the desired current through the two cells in series .....but the idea is that for every mole of PbO2 which is plated onto the anode substrate in the first tank .....exactly the same mole of Pb metal will be driven into solution as a result of dissolution of the lead sheet anode in the second tank .

[Edited on 7-6-2007 by Rosco Bodine]
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Twospoons
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[*] posted on 7-6-2007 at 15:13


Here's a synthesis for magnetite, to go with Rosco's "lead + magnetite" patent.

[Edited on 8-6-2007 by Twospoons]

Attachment: magnetite_Synthesis.pdf (124kB)
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Helicopter: "helico" -> spiral, "pter" -> with wings
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Rosco Bodine
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[*] posted on 7-6-2007 at 16:11


The patent did say that the synthetic magnetite material could be used :D

In some of the patents which I have seen describing electrodeposition , there has been reference to producing a composite plating from a bath containing
suspended particles which become trapped in the layer of material being plated .....even inert particles of silica or teflon can be trapped in the material being plated to form a composite . So I wonder if a composite plating of lead metal having entrapped particles of magnetite might be made this way , or in some variation of the method .
It would probably result in an even denser layer of better interlocked materials than any sintering could achieve .

Magnetite is also a material of interest , along with some other conductive oxides , like tin , titanium and bismuth ,
which have interest as possible components of a conductive ceramic or glass . Such a composite material could be a sort of holy grail anode material , even if it ended up requiring arc furnace temperatures to melt the stuff .

[Edited on 7-6-2007 by Rosco Bodine]
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Rosco Bodine
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[*] posted on 8-6-2007 at 08:53
Perchlorate Cell same as Bromate Cell


Earlier in the thread I pointed out the Bromate Cell article
which is posted on the following page
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/...
saying that the massive PbO2 anode described for the bromate cell is applicable to a perchlorate cell also ,
and this has been confirmed by the attached article .

The massive PbO2 anodes were used in service for two years without failure , and the anodes were originally grown on an *iron* substrate .

Hmmmm , Guess that means for a temporary substrate .....

All you need is iron ,
All you need is iron ,

All you need is iron , iron .....

Iron is all you need
Iron is all you need
Iron is all you need

:D:D:D:P:D;):cool::cool::cool::D:D:D:D

Sound familiar ????

[Edited on 8-6-2007 by Rosco Bodine]

Attachment: Electrolytic Production of Perchlorate by Lead Dioxide Anodes JES 116 Issue 2 pp 203-207.pdf (625kB)
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[*] posted on 8-6-2007 at 17:15


Hello,

So it's back to the five tanks, pump, two stirrers, 66 hours (monitored if not using good automatic equipment) plating time, heater, no mention of tank size, but probably bigger than any tank I (you?) are willing to afford.


All you need is a stack of cash
a stack of cash....
[insert looney tune here]


Good night.

Dann2

:D
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[*] posted on 8-6-2007 at 18:28


I wonder how much this place wants for PbO2 anodes? It seems once you're making them on a production line it shouldn't be all that expensive...especially in a country like India. I think I'll email them and ask the price.

http://www.titanindia.com/ledma.htm
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Rosco Bodine
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[*] posted on 8-6-2007 at 19:14


Quote:
Originally posted by dann2
Hello,

So it's back to the five tanks, pump, two stirrers, 66 hours (monitored if not using good automatic equipment) plating time, heater, no mention of tank size, but probably bigger than any tank I (you?) are willing to afford.


According to you it's that way , because you aren't considering what I said already about it being much simpler .
I even posted a picture of an inline magdrive pump ,
and attached a patent US2492206 , drawing Fig.4 showing a simpler plating arrangement to make it clear . I said you need to think outside the box concerning the industrial scale to lab scale conversion , and see how the process can be adapted .

But you have such tunnel vision about titanium substrate
anodes , that you seem in denial that tons of perchlorates
have been made using less technically difficult and less expensive anodes . I even posted a patent which showed
how bare graphite anodes have been used in divided cells
that did work , a long time before any internet usenet dubious designs may have oversimplified what was required . Even so graphite works for somebody who knows how it must be used , and dittos for PbO2 .

The massive PbO2 anodes of the JES Bromate and Perchlorate articles are essentially the same size as
what alembic made on a titanium substrate , and the same precise control of the bath conditions is required for the
making of either . The real difference between the two
is that the low tech version is cheaper and easier to make
and will last longer .

But to those who are singing the praises of titanium substrate , the truth of that is irrelevant .

Quote:

All you need is a stack of cash
a stack of cash....
[insert looney tune here]


A stack of cash isn't required unless you are shopping for
titanium and the dopants needed , when NONE of that is required .....but is simply a high tech way of producing
a perchlorate anode substrate that is inferior to the working material that coats it , and producing a composite that is no better than its weakest link . Keeping at that effort is what seems looney . I mean what is the point ? You go on and on about the complexity and fragility of a massive PbO2 anode , when that design has been proven in commercial use to be the most easily and economically attained of the durable anodes . On your website you even said that the best substrate is no substrate at all , so I should be preaching to the choir here . But I guess you are now
dedicated to the "false religion" of titanium substrates
and exotic "paint and bake" semiconductor junctions , which
then get what for advantage but many prayers the sacred
coatings don't crack .

Quote:

Good night.

Dann2

:D


Good night indeed !
Jesus Christ would be more like it ....:D
but then who's swearing?

Think of PbO2 on iron as that "old time religion" that just works , and stop hanging out with the Moonies and the Dianetics crowd !

Where I am at now is choosing the best scheme for keeping the Pb content and pH of the plating bath constant .
I grabbed all sorts of references for the preparations
of the basic salts that would be the simplest way . And I have also been looking at the possibility of using an active
electrolytic method for doing this ....but will probably just use
the percolator funnel setup since it is simpler .

I have found another patent which further substantiates
that industry has used not just iron but steel as a substrate
on which to electrodeposit PbO2 for massive anodes . I found a patent which describes a method used by the plating shops for cleaning the substrates of PbO2 residues
prior to the replating of new PbO2 anodes . It is US5487820 attached . Given these patent and literature references
which are related to industrial use of long lived and durable and cheap massive PbO2 anodes , which have also been prototyped on a lab scale , a few people seem to be in some sort of denial that this would be a very logical approach .

And all I can say to the notion that somehow *any* substrate is going to be superior to the massive PbO2
configuration .....is :roll: , hope springs eternal .

BTW .....WTF happened to the roll eyes icon ,
was it not PC ??? I mean was it too provocative and insensitive , too offensive to any genuine intellectuals
who otherwise might contribute something here if
only this were a more tolerant and nurturing environment :P

There are several patents which have mentioned the use of
steel or iron as a temporary substrate upon which massive PbO2 anodes may be plated . US2846378 , US2945790 ,
US4064035 are three of them and there are others I don't have handy . Those patent references along with the JES
description are very thorough and credible . And according
to US4064035 it is less than a one day plating time to buildup
a massive PbO2 anode .

From everything I have read this looks like the best way to go and has been well proven for fifty years .



[Edited on 9-6-2007 by Rosco Bodine]

Attachment: US5487820 removing PbO2 from steel substrate anode.pdf (49kB)
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[*] posted on 9-6-2007 at 06:00


Rosco, are you declaring a Jihad against titanium? Are not ALL elements precious in the eyes of God? Can't ALL the elements just get along, preferably in complex, intricate, interesting ways?

:P:D;)
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Rosco Bodine
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wink.gif posted on 9-6-2007 at 09:51
old time anode hour from the lead crystal cathedral


Woe unto you sinners ! Hear the word of Plumbum ,
heed the word of Plumbum , thus sayeth Plumbum .

I AM your perchlorate anode , PbO2 .
Thou shalt have no other perchlorate anodes before me .
For I your PbO2 perchlorate anode , am a jealous perchlorate anode . I will bless them who bless me , and curse them who curse me , even to the third generation :P

On my right hand , since from the beginning there was iron , and all ye who knoweth me shall rule over the plating baths with a rod of iron ;)

I know the works of those who goeth the way of titanium and platinum and how the false prophets deceived them
with miracles to cause them to be astonished and bow down before false anodes . Surely all of these shall have their reward in the day of corrosion :D

BTW , here is the pdf for that JES article on bromates
which Dann2 has on his website as a jpg file . This is such an important reference , it needs archiving in that
conventional file type . @ dann2 , please for any of the
files which you may accumulate related to your website , if you have the root files in pdf , link them , as they are
simpler to handle for printing , ect .

In that patent US4064035 , which mentions iron as a suitable substrate for massive PbO2 anodes , it further
says that following the plating , the iron substrate may be etched away by acid .....but gives no further details
concerning this method of stripping the massive PbO2 anode from substrate . I am wondering specifically what
composition of etchant would be most desirable , which
would thoroughly eat away the iron , while not attacking the PbO2 in any harmful way . Perhaps a mixture of
hydrogen peroxide and sulfuric acid ? Any ideas what
would be good for this ?

Attachment: JES 104 Electrolytic Production of Bromates.pdf (383kB)
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[*] posted on 9-6-2007 at 10:19


I think if you just operate the anode in a chlorate cell, maybe with some additional HCl, the iron will dissolve, maybe plating out on the cathode. Or maybe set up something like a lead/acid battery with stainless steel cathode. Make high purity electrolytic iron.

This could also turn into a Holy Crusaide! Pure Iron (Armstrong Iron) is as scarce as Archaeopterix teeth. Pure Iron crucibles, or heavily plated with pure iron crucibles would be very useful for experiments with molten Lithium compounds. Everything else seems to react or dissolve (although I suspect pure alumina crucibles would form a protective layer of lithium aluminate below 1200 C.)
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Rosco Bodine
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[*] posted on 9-6-2007 at 10:46
iron plating on aluminum pistons


Iron can be plated onto aluminum as can nickel .
This might have some usefulness . See US5368719 .

BTW , my EDM graphite arrived . I have several sheets
that are 8 mm thick , 125 mm wide , 375 mm long .
I was going to split them lengthwise as substrates for
PbO2 . I also got some round rods 1" and 3/4" for
GSLD experiments .

My time for any of this is about to get hijacked for awhile
as I have assorted other business which requires my attention
and I am reaching a "stopping point" where I
pretty much have the research done , and can implement
and experiment later . This seems to be the story of my life ,
spending time digging up references and getting experiments
planned , and then having no time left to do the fun part . I have a stack of hardcopy file folders two feet high of uncompleted experiments , and boxes of unassembled parts for apparatus for uncompleted projects ....I swear I need three or four assistants and a secretary . Posting some of it here , maybe somebody else can make use of the information and ideas already accumulated .

Attached is a good primer concerning the conditions under which various forms of lead oxidation products are evolved and/or electrodeposited .



[Edited on 9-6-2007 by Rosco Bodine]

Attachment: JES The Anodic Oxides of Lead.pdf (957kB)
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dann2
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[*] posted on 9-6-2007 at 16:02


Hello,


Quote:
Originally posted by Rosco Bodine




But you have such tunnel vision about titanium substrate
anodes , that you seem in denial that tons of perchlorates
have been made using less technically difficult and less expensive anodes . I even posted a patent which showed
how bare graphite anodes have been used in divided cells
that did work , a long time before any internet usenet dubious designs may have oversimplified what was required . Even so graphite works for somebody who knows how it must be used , and dittos for PbO2 .


The patents never tell you what the failure rates of anodes are. The product they have made/discovered is ALWAYS the best thing since sliced bread.
It is my opinion that the massive, GSLD, ceramic substrate, and any corrodable substrate needs all stops pulled out on quality of plating set up. If you can come up with a cheap set up as a substiture for LARGE tanks and a number of them then that will be great.
Perhaps the Ti with doped Tin will be more forgiving when corners are cut.
Ti is easy to obtain. The substrate will conduct current to the Lead Dioxide if the coating is not perfect and it is self healing where the Lead Dioxide has a hole or imperfection in it.
That is a good starting point for the whole show.
There are no other substrates (bar the possibility of Magnetite but thats another story) that have theses advantages. It must be coated with something (doped Tin) to link the Ti with the Lead Dioxide. But that is not too difficult (we hope).
Quote:

The massive PbO2 anodes of the JES Bromate and Perchlorate articles are essentially the same size as
what alembic made on a titanium substrate , and the same precise control of the bath conditions is required for the
making of either . The real difference between the two
is that the low tech version is cheaper and easier to make
and will last longer .



Massive, Ceramic based, Graphite based cannot be described as low tech. They will kick you in the butt if the coating is not perfect.
Perhaps the doped Tin coated Ti will do the same if all stops are not pulled out on quality of coating set up but we will have to see.
The other substrates have been tried again and again by others out there with out much success.


Quote:

But to those who are singing the praises of titanium substrate , the truth of that is irrelevant .

The other substrates are old and tired and tried again and again. The Ti is the new kid on the block and will work. Have faith!!!!!!!!!
The other have been cursed (literally) by many.

Quote:


You go on and on about the complexity and fragility of a massive PbO2 anode , when that design has been proven in commercial use to be the most easily and economically attained of the durable anodes . On your website you even said that the best substrate is no substrate at all , so I should be preaching to the choir here . But I guess you are now


The Massive anode has not been proven in low tech (one tank) amateur circles. The other substrates have been a bad job too.
I was the first to start singing the praised of the ceramic subatrate anode a long time ago (when god was running around in wee pants, (now that IS quite a while ago)) but is proved to be a totally useless hopeless substrate. Read the patent. It is the best, most robust, better than anything before anode. No mention of salts being conducted up the the connections etc.
On my site I sing the praises of the Massive anode in the form of the Cloth Substrate Anode. I think it is a possible way to go. A piece of cloth (or what ever beats the hell out of Graphite price wise.)

Quote:

dedicated to the "false religion" of titanium substrates
and exotic "paint and bake" semiconductor junctions , which
then get what for advantage but many prayers the sacred
coatings don't crack .


No need to pray quite so hard with the Ti based product as you will need to pray with the non self-healing substrate (or the cracking and falling apart massive (not reinforced with cloth type)) anodes.
With the non self-healing type substrates I suggest a pilgrimage [prayers will be useless]. With the massive (not reinforced with cloth) I suggest you do the pilgrimage on you nees!

Quote:


BTW .....WTF happened to the roll eyes icon ,
was it not PC ???

Yes. If you resurrect that thing I'm leaving :-|


Quote:

....massive PbO2 anode .

From everything I have read this looks like the best way to go and has been well proven for fifty years .


They have been proven for fifty years to be problemetic. This I have read in many places. Low yield when making. Prone to cracking.



Dann2
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Rosco Bodine
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[*] posted on 9-6-2007 at 18:45


Quote:
Originally posted by dann2
Hello,


Quote:
Originally posted by Rosco Bodine




But you have such tunnel vision about titanium substrate
anodes , that you seem in denial that tons of perchlorates
have been made using less technically difficult and less expensive anodes . I even posted a patent which showed
how bare graphite anodes have been used in divided cells
that did work , a long time before any internet usenet dubious designs may have oversimplified what was required . Even so graphite works for somebody who knows how it must be used , and dittos for PbO2 .


The patents never tell you what the failure rates of anodes are. The product they have made/discovered is ALWAYS the best thing since sliced bread.

Yeah you can get that from reading of the patents about the titanium substrate anodes , especially when they fail to provide perchlorate cell performance data , it would seem to be a glaring omission .



Quote:

It is my opinion that the massive, GSLD, ceramic substrate, and any corrodable substrate needs all stops pulled out on quality of plating set up. If you can come up with a cheap set up as a substiture for LARGE tanks and a number of them then that will be great.


Yeah I have already spoken to that twice . The scale is different for producing one 40 Amp anode , than for making a dozen that size at one time , and you don't need as much plumbing to accomplish the same thing . It isn't required to have the same arrangement .....only the same functions . Scaling down often simplifies things .

Quote:

Perhaps the Ti with doped Tin will be more forgiving when corners are cut.


Why would you think that any corners could be cut making an anode which has a compromisable substrate buried at its core ? If anything , the plating is even more important to be
impermeable . And as for the substrate being self-healing ,
well is that indeed a capability for the valve metal substrates ? I missed that in the titanium substrate patents
which I was reading . It was my understanding that when their oxide layer was breached , they were history .


Quote:

Ti is easy to obtain. The substrate will conduct current to the Lead Dioxide if the coating is not perfect and it is self healing where the Lead Dioxide has a hole or imperfection in it.


References??? Again it was my understanding that
during service in the perchlorate cell , there is no self-healing
for titanium substrates , they corrode , only more slowly ,
if their semiconductor oxides are breached , which occurs
sometime not so long after the PbO2 layer is breached ,
similarly as occurs for graphite . The PbO2 will even separate from a platimum substrate , if the PbO2 is permeated by electrolyte while in service .

Quote:

That is a good starting point for the whole show.
There are no other substrates (bar the possibility of Magnetite but thats another story) that have theses advantages. It must be coated with something (doped Tin) to link the Ti with the Lead Dioxide. But that is not too difficult (we hope).


So are you saying the semiconductor oxides coated titanium
has the same self healing bielectrode activity as occurs with
lead-platinum , and lead-magnetite ...and is this proven to work in perchlorate cell conditions that the self healing occurs ? Again ....what references ?



Quote:

Quote:

The massive PbO2 anodes of the JES Bromate and Perchlorate articles are essentially the same size as
what alembic made on a titanium substrate , and the same precise control of the bath conditions is required for the
making of either . The real difference between the two
is that the low tech version is cheaper and easier to make
and will last longer .



Massive, Ceramic based, Graphite based cannot be described as low tech. They will kick you in the butt if the coating is not perfect.
Perhaps the doped Tin coated Ti will do the same if all stops are not pulled out on quality of coating set up but we will have to see.


I think you may rely upon it that carefully controlled plating conditions for the PbO2 are going to be required in any case . No sloppy work is going to produce a good anode no matter what configuration it is .



Quote:

The other substrates have been tried again and again by others out there with out much success.



Maybe the "peer review" problem there is that the reviewers
aren't duplicating the conditions of what it is they are reportedly debunking . There is a lot of that going around you know , so some of this I just have to see for myself .
When there is so much of what should be reliable literature
on a subject that is so mundanely industrial , and such controversy erupts .....you would find even in the text of the literature itself many disputes of the findings of earlier workers very prominently published ...and I haven't been seeing that in literature spanning decades of work , so it just doesn't wash that the data or its continuity is likely to be unreliable . Maybe it is unreliable only for those who are
not seriously adhering to the science and doing good work , but are making half-assed attempts which fail , and then
saying that the published science is bad instead of their own methods .


Quote:

Quote:

But to those who are singing the praises of titanium substrate , the truth of that is irrelevant .

The other substrates are old and tired and tried again and again. The Ti is the new kid on the block and will work. Have faith!!!!!!!!!
The other have been cursed (literally) by many.


There is nothing tired about a perchlorate cell that has an array of 10 anodes running for two years without replacement of a single one due to failure . I'd say that's a pretty solid proof of concept . And if it wasn't , you can bet your ass that the peer review process would have crucified
the authors as if they had been reporting cold fusion .
There would be plenty of debunking , done loud and long
in the same journal and in other places .....so where is it ???
If the technical accuracy is not there , then where are the
subsequent articles clarifying the matter ????

Quote:

Quote:


You go on and on about the complexity and fragility of a massive PbO2 anode , when that design has been proven in commercial use to be the most easily and economically attained of the durable anodes . On your website you even said that the best substrate is no substrate at all , so I should be preaching to the choir here . But I guess you are now


The Massive anode has not been proven in low tech (one tank) amateur circles. The other substrates have been a bad job too.

If you are looking for a low tech process that is good for amateurs to produce perchlorates .....good luck !!!
I'm serious , nothing about this is really going to tolerate
an absence of quality control , and kitchen chemistry this is not . Chlorates , yes sure .....perchlorates ? No easy
non-technical way .


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I was the first to start singing the praised of the ceramic subatrate anode a long time ago (when god was running around in wee pants, (now that IS quite a while ago)) but is proved to be a totally useless hopeless substrate. Read the patent. It is the best, most robust, better than anything before anode. No mention of salts being conducted up the the connections etc.

So what ! It requires the same silvered connections same as would a massive anode . Why shouldn't it ?

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On my site I sing the praises of the Massive anode in the form of the Cloth Substrate Anode. I think it is a possible way to go. A piece of cloth (or what ever beats the hell out of Graphite price wise.)


And a silvered connection will be required there too .


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dedicated to the "false religion" of titanium substrates
and exotic "paint and bake" semiconductor junctions , which
then get what for advantage but many prayers the sacred
coatings don't crack .


No need to pray quite so hard with the Ti based product as you will need to pray with the non self-healing substrate (or the cracking and falling apart massive (not reinforced with cloth type)) anodes.

Cracking and falling apart massive anodes ??? Ten of them
running together for 2 years and not one failed is not a story of fragile anodes ...so what is the truth here ?

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With the non self-healing type substrates I suggest a pilgrimage [prayers will be useless]. With the massive (not reinforced with cloth) I suggest you do the pilgrimage on you nees!

There you go again with the claim/inference that titanium is a self-healing bielectrode substrate . So where are you getting this information ??

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BTW .....WTF happened to the roll eyes icon ,
was it not PC ???

Yes. If you resurrect that thing I'm leaving :-|

We desperately need to get a Lazarus edition of the roll eyes smilie , maybe have a user option to hide it from the thin skinned ;)

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....massive PbO2 anode .

From everything I have read this looks like the best way to go and has been well proven for fifty years .


They have been proven for fifty years to be problemetic. This I have read in many places. Low yield when making. Prone to cracking.

Dann2


Again , where are you getting this information ????
And don't you find it strange that this contradicts what
the journals and patents describe . I am sure there are
incremental improvements even in the art of manufacturing accordions . But that doesn't mean nobody could play a tune on the ones that were made a hundred years ago ,
or that half of those attempted to be made had to be scrapped as firewood . It isn't like there wasn't some alternative before the invention of fiberglass and electric
organs .
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12AX7
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[*] posted on 9-6-2007 at 20:19


Dann: some helpful information.

Leave Rosco alone. It's obvious that he is pushing away all your ideas and leading a rather obnoxiously long argument. Be the better man and win the argument by not replying. He tends to do this, and regardless of the value of his chemical knowledge, he is a terrible person to try to sway.

Changing subject here...

Has anyone tried, say, a lead anode in a high-sulfate solution? Sulfate tends to yield lead dioxide on the anode. Chloride gives a mucky combination of hydroxide, chloride and dioxide, but maybe less chloride (or even starting with chlorate) will be capable.

I suppose the chemical reaction is that, since to metal, chlorate and perchlorate simply corrode it (giving soluble lead), a "catalytic" side-reaction has to be performed, in this case where sulfate oxidizes to persulfate and PbO2 and that sort of stuff. Then the PbO2 is able to oxidize the chlorate. Efficiency will be lower since electrons are spent maintaining a PbO2 layer and producing oxygen, but it would be cheap as hell if all the preparation necessary is lead, possibly dioxidized some before use.

Tim




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Electronic Design, from Concept to Layout.
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[*] posted on 9-6-2007 at 20:54


Quote:
Originally posted by 12AX7
Dann: some helpful information.

Leave Rosco alone. It's obvious that he is pushing away all your ideas and leading a rather obnoxiously long argument. Be the better man and win the argument by not replying. He tends to do this, and regardless of the value of his chemical knowledge, he is a terrible person to try to sway.


Tim , I am most definitely *not* simply trying to argue , but really to get at the facts , not anecdotal IMHO's or "I have heards" but good technically valid data . For example , the matter of the bielectrode self-healing substrate aspect of
titanium substrate anodes ....I really didn't catch that detail in any of the stuff I read .....so asking for references was no argument . I really want to know more on that , because the first I saw of it was with the sintered lead and magnetite
scheme , and I never heard of it before , except being used as a galvanic couple for zinc granules having copper regions used as a reducing reagent ....not as an anode .

Really I am not trying to complicate things . And I may be terrible to try to sway when I am right about something ,
but I am not so unreasonable as not to see it or admit it
where anybody can show me I am wrong . I certainly can be wrong about some things , ..... rarely:P

Quote:

Changing subject here...

Has anyone tried, say, a lead anode in a high-sulfate solution? Sulfate tends to yield lead dioxide on the anode. Chloride gives a mucky combination of hydroxide, chloride and dioxide, but maybe less chloride (or even starting with chlorate) will be capable.


I saw one process described where lead metal was first high current plated onto an etched anode , and then the current reversed to anodize it to PbO2 in order to improve adhesion , as it worked better that way than trying to plate on the PbO2 first ....I forget what was the metal substrate , but it worked best to go metal to metal first in that particular case .
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I suppose the chemical reaction is that, since to metal, chlorate and perchlorate simply corrode it (giving soluble lead), a "catalytic" side-reaction has to be performed, in this case where sulfate oxidizes to persulfate and PbO2 and that sort of stuff. Then the PbO2 is able to oxidize the chlorate. Efficiency will be lower since electrons are spent maintaining a PbO2 layer and producing oxygen, but it would be cheap as hell if all the preparation necessary is lead, possibly dioxidized some before use.

Tim


Are you talking about the bielectrode self-healing PbO2 effect ? It is not established that this is protective in a
perchlorate cell , from anything I have read , but it would be great if it did work . I think what it does is add a galvanic voltage locally which may or may not be effective in a perchlorate cell .....I found nothing else on this .
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[*] posted on 9-6-2007 at 22:22


Rosco, I think what dann2 means when he uses the term "self healing" is that Ti stops conducting and becomes inert in anodic conditions. If a pin hole develops through the lead dioxide and then through the semiconducting layer, it gets to the Ti and anodizes and corrodes no further. It would only break down and corrode if you cranked up the voltage far above what should be present in a perchlorate cell. Obviously the substrate isn’t going to cause the outer peroxide layers reform, the substrate in that spot just becomes inert, so it won’t matter if a hole or crack develops. The whole point of the semiconducting layer is to get past that property of Ti so it can be used in anodic conditions, but if that fails the Ti will just go back to its old self again and reform a nonconducting TiO2 protective layer.

-Alan
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[*] posted on 10-6-2007 at 01:16


Quote:
Originally posted by alancj
Rosco, I think what dann2 means when he uses the term "self healing" is that Ti stops conducting and becomes inert in anodic conditions.

Yes , I see what you mean by the insulating of the titanium by titanium oxide interface with the electrolyte , the anodizing would then block current flow there from the electrolyte solution to the metal . But it was my idea that the
insulative area would still be attacked by the chlorine ion which would penetrate that protective oxide , and that the effect would also spread underneath the PbO2 layer causing it to flake off . A variation on the same thing happens even when the substrate is platinum due to the different oxygen evolution voltages bewteen platinum and PbO2 . Oxygen spreads like a sheet of marbles between a carpet and a floor , wedging between the interface and prying the PbO2 away from the platinum . Maybe it has a greater surface tension / adhesion for the platinum and maybe chlorine is involved also , but whatever the mechanism , the PbO2 separates , once electrolyte gets under it . If that effect is absent using the doped semiconductive oxides , so that delamination does not proceed ....then all that would happen
at the location of an area of exposure of the substrate , is that exposed area would simply go inert . I am very dubious about that happening though , particularly in an electrolyte
where a fluorine additive is present ....it just smells like real trouble for the titanium that gets touched by that fluorine , since if the chlorine didn't get at it you can bet the fluorine would . The voltage would be a factor , but that would just accellerate things . I am guessing here . I haven't read the test data . I am sure , now that I think about it , I remember this was definitely mentioned about the use of fluoride .
Maybe a persulfate additive would be better when a titanium substrate anode is in the cell .
Quote:

If a pin hole develops through the lead dioxide and then through the semiconducting layer, it gets to the Ti and anodizes and corrodes no further. It would only break down and corrode if you cranked up the voltage far above what should be present in a perchlorate cell.

Yes I follow what you are saying that it passivates the exposed titanium when electrolyte contacts the metal .
And *if* that is what happens then it would be okay .
So long as the conductive real estate in the surrounding neighborhood isn't affected , it would keep working .
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Obviously the substrate isn’t going to cause the outer peroxide layers reform, the substrate in that spot just becomes inert, so it won’t matter if a hole or crack develops.
It is more like a self-sealing than a self-healing actually .
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The whole point of the semiconducting layer is to get past that property of Ti so it can be used in anodic conditions, but if that fails the Ti will just go back to its old self again and reform a nonconducting TiO2 protective layer. -Alan

Yeah , I see what you are talking about with the semiconductor layer . They are basically lowering the reverse
breakdown voltage of the diode junction at the Ti-TiO2 interface so that current can be made to flow backwards through it and into the PbO2 layer . PbO2 actually forms a
rectifying junction on a "blued titania" over titanium substrate . Sheesh I'm not sure , the polarity may be backwards on this one or the reverse breakdown voltage too high for anodic applications , but see the attached
patent US2711496 for any relevance it might have . Curiously , amorphous PbO2 also forms a photorectifier junction on a copper substrate , see US4173497 if that
is of any interest . The point is that the PbO2 itself is an added semiconductor in these layered structures which
could have exactly the wrong polarity , if I have this right ,
and form a blocking diode depending upon what else is
in the "sandwich" of layers . Basically with these doped
oxide layers on titanium then covered with PbO2 what you have assembled is one giant planar zener diode of sorts serving as an anode ? I'll have to go back and refresh read a chapter on semiconductor theory to make sure I have this right :D

BTW , that same patent that was refrenced by Alembic
US2872405 had described using the corrosive effect of
the chlorate cell itself to etch away an iron substrate and leave the massive PbO2 anode intact , without risking breakage by trying to pry it away from the substrate on which it was deposited . So I didn't just dream up that idea
but probably read it and then forgot it . I think Alembic originally gave a British patent number equivalent and I didn't make the connection . Anyway that patent did use
a lower plating curent and did take days for plating a
massive PbO2 anode , but a later patent US4064035 much improves the process in a couple of ways including reducing the time for plating . So there's nothing wrong with gleaning
the best parts from different patents and then combining those refinements . Another patent from the same folks
as Alembics patent reference , is US2859166 which was
a co-application , and it tells more about the use of temporary steel substrates being conventional in the
manufacture of massive PbO2 anodes ....which it also says are very well adapted for the production of perchlorates ,
and should be produced in a thickness of 1/2 to 1 inch
for added strength . Probably the geometry and scale of the anode has an optimum ratio of width , length to thickness
and that is on the large side for commercial sized production anodes . That patent specifically deals with shielding and baffles used in a cell to prevent treeing and produce smooth and even deposits of PbO2 laid down in thick layers to produce such gargantuan PbO2 anodes .

Anyway , I think I'll rest my case that massive PbO2 anodes
are simpler and well proven and involve the same technical requirements for getting the PbO2 part of the assembly done right , as will be required even for the alternative configurations . It just seems much easier to let the same
plating bath run longer , do the silverplated contact , and have a commercial grade production capable anode ...
without venturing into silicon valley styled planar rectifier manufacture , especially if the idea is that simplicity must be kept to what is convenient for a "hobbyist" . Personally my impression is that any of this stuff is well beyond the realm
of most hobbyists and well into the realm of pretty nerdy madscience and its practitioner technicians :D , even for
the simpler configurations .

Attachment: US2711496 Blue Titanium Conductive Oxide Anodization.pdf (295kB)
This file has been downloaded 882 times

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[*] posted on 10-6-2007 at 01:25


Rosco Bodine, why do you insist to make a massive anode without any subtrace. Dont you think that it would be better to make a thinner anode but with a cloth inside it to improve its phisical strength. Also because you dont plate that much PbO2 so you dont really need to controll the PH which i think is the main problem of the massives. I dont think that anyone would like to make a huge bath (to handle kilograms of lead nitrate) and then to put in pumps (that i think wont make the trick because they do have metallic parts inside them, and we dont really know what is the metal that this part is made of and what will it cause to the tank)
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[*] posted on 10-6-2007 at 02:46


I am not insisting that anyone make a massive PbO2 anode without any substrate . It does decrease some the demand for carefully controlled conditions (but it does not eliminate completely the need for any regulation) and is probably the surest , simplest way to make a practical anode *if* you accept the fact that you are going to have to silver the connection .

Some of the magdrive pumps would work fine and have wetted parts that are only polypropylene and ceramic .

It depends on the *size* anode you are trying to make ,
what may look like the best way to go . Lead is very heavy , and it will take a good bit to make a 40 Amp
anode , plus the extra third length needed for the distance above the electrolyte to the silvered connection .
Yes it takes kilograms of lead salts for this , and even
for a cloth substrate anode .....which is still a massive
PbO2 anode . And you will be surprised how little lead
being plated out will drastically change the pH if you aren't actively regulating the pH in some way .

Scaled down , everything is simpler in some ways ,
but not in others .
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[*] posted on 10-6-2007 at 03:59


I was thinking that the surest way to control pH (and therefore lead ion concentration) would be to use a pH probe in the plating tank, and interface that with a microcontroller to drive a small auger to deliver salts to an addition tank, which is circulated with the plating tank. (oddly enough, I live a half mile away from a company that manufactures augers for pellet stoves!) Maybe just knowing the plating deposition rate one could do it without automatic feedback, and skip the probe. I think that is what you'd have to do with an acidic plating bath at least. For a neutral one I think a percolation funnel would be fine, like Rosco mentioned. IMO it would be pretty hit or miss trying to get a lead compound with the right properties so as to dissolve at the exact rate you want at the exact pH etc., in anything but a neutral plating bath.

-Alan

edit: auger not agar!

[Edited on 10-6-2007 by alancj]
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[*] posted on 10-6-2007 at 04:09


There goes an interesting question :
If we do hang something like a tea bag of lead carbonate(or any other lead compund that will react with HNO3) what will happen? will the trace amounts of HNO3 forming will react immediately with the lead compund hence making a neutral bath. Or because of no movement in the tank the only reaction will be caused by drifting of the solutions and making quite stable acidic PH?
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