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jpsmith123
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I'm surprised an electronics place has it. Over here it's mainly used for plumbing applications. And it seems to be slowly being replaced by Sn/Ag.
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Rosco Bodine
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I've seen 95/5 solid wire in the hardware sections
of stores on carded 4 oz rolls , but it seems to be
getting replaced by other alloys .
It looks like the alloys that contain bismuth should
also be a priority . It is strongly suspected that bismuth is
the likely material which supplies a catalytic selectivty to
the anode coating for producing perchlorate , as opposed
to the anode dumping its energy early at too low a voltage by preferentially evolving oxygen and or chlorine , or becoming involved in some sort of
unfavorable equilibrium where the reaction doesn't go to completion for perchlorate .
There is definitely a surface chemistry reaction on the anode surface which involves more than just the
voltage potential on inert spectator anodes . Absent
that selectivity about the anode , the cell could just
run forever happily making hydrogen and oxgen from
the water .
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jpsmith123
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I wonder if the SnO2 - Sb2O3 - Bi2O3 - etc. film could be made from a gas-flame-oxidized metal film?
Maybe if someone has a relatively high temperature solder pot (I've seen some advertised as going over 500 C) they could try an experiment.
Suppose a piece of titanium is hydrided and then immersed in molten Sn/Sb/Bi. Then if the temp is made to rise further to the range of 400 - 450 C,
maybe the hydride will decompose and the metal will wet the titanium.
Then the coated titanium could possibly be heated in air with a gas flame to 550 degrees C or more and the coating converted to oxide?
Although even if it works it may not be much less burdensome than repeated dipping and baking anyway.
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Rosco Bodine
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Ineteresting idea .
It would be a very easy solution if it worked .
Just have an anti-passivation tinning / DTO precursor
"instant anode alloy" , tin that sucker and then fire it up
This idea tracks parallel with something I was thinking about awhile back using an amalgam solder / flux mixture to defeat the passivation layer and
then just cooking off the mercury in a furnace hot enough to do the job . It seems plausible .
That was basically an interface alternative idea though ,
and it wouldn't work except for the first coat . You
would still need the subsequent layers added thickness
for wear . A millimeter or so coating is probably needed
for a few thousand hours service , so the one coat would only work for and inconveniently short time although
unlike the plain spinel one coat , it probably would make perchlorate . Some lead might have to go into that alloy .
These may be of interest , just found them and it raised an eyebrow because it sort of fits what I have been thinking
http://dx.doi.org/10.1016/S0167-2738(98)00410-X
http://dx.doi.org/10.1016/0167-2738(94)90400-6
http://dx.doi.org/10.1016/j.jeurceramsoc.2007.02.106
These articles have been reviewed but appear to be using methods and temperatures which are not really pertinent
to the coatings application we are contemplating , but rather involve ground materials and compressed pellet sintering of materials for sensors . So I
am not going to attach these here .
[Edited on 20-12-2007 by Rosco Bodine]
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Rosco Bodine
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| Quote: | Originally posted by dann2
Hello,
@Roscoe
Do you have any Anode patents involving DTO that have a low Sb content in the DTO coating that do not substitute something else (Nobels) for the
Antimony.
You stated that they were posted to the board. I am unable to find any.
Dann2 |
Here's a more interesting reference than the ones posted earlier , as the same source did some comparisons on
longevity of some of these doped SnO2 coating schemes , using accellerated wear " torture test " conditions .
Curiously also this is the *only* reference I have found
where cobalt doped SnO2 is referenced specifically in
regards to the intermediate layer anode coating application .
I had supposed this was possible , but until now had found
nothing specific .
This is a very interesting reference also with regards to
another idea involving doping of TiO2 . This suggests that indeed it is possible to use a controlled thickness TiO2 oxidation surface on titanium ,
as for example a brief anodizing in 50% KOH , followed by doping by diffusion
from a subsequent layer . A variation on the rectifier patent
US2711496 using for example a cobalt dopant , and perhaps
some others should result in a doped TiO2 interface that is
conductive and essentially non-rectifying baked interface ,
though no examples are given . The thickness and chemistry
of the TiO2 layer would likely have bearing on how well this may work for particular dopants .
[Edited on 20-12-2007 by Rosco Bodine]
Attachment: US4584084 Co2O3 v Sb2O3 and other DTO dopant comparison tests.pdf (272kB)
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dann2
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Hello,
See US 4,839,007 for an SnO2 only anode. They claim that the SnO2 has a very high O2 Overpotential.
There for it shoud be OK for Perclorate? if it does not corrode I guess.
Dann2
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Rosco Bodine
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That's a good find .
If it is accurate information , yeah it should work but different and lower figures are given US4208450 .
There is also a catalytic material involved for perchlorate
anodes . The coating needs to be chemically favorable
for the formation of the pechlorate .
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dann2
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Hello,
DTO makes Perchlorate. I have run a jam jar cell making Na Perchlorate untill the Li came along.....
I have uploaded some papers sent to me from RongPeng.
They related to SnO2, +++++
Available here:
http://mihd.net/lqk84u
Dann2
[Edited on 22-12-2007 by dann2]
[Edited on 22-12-2007 by dann2]
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Rosco Bodine
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| Quote: | Originally posted by dann2
Hello,
DTO makes Perchlorate. I have run a jam jar cell making Na Perchlorate untill the Li came along..... |
It may not have been the Li , it may have just
been the DTO reaching the end of its numbered days
which would have occurred in any electrolyte .
| Quote: |
I have uploaded some papers sent to me from RongPeng.
They related to SnO2, +++++
Available here:
http://mihd.net/lqk84u
Dann2 |
Read with interest .
The adhesion problems that were encountered for the
ATO-Ti interface may be cured by a Co spinel interface , which by diffusion into a subsequent ATO layer results in a more dense and conductive layer
which should have lower oxygen permeability as well . And lower temperatures are required for the process variation .
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dann2
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Hello,
Just to sum up how my DTO 'Anode' test turned out. I started it on 29 Nov. It had been running untill about 2 days ago (The Li put an end to it's
gallop). Subtracting 3 days from this to allow for times when I was using the power supply for other things this means that it lasted approx. 450
hours, most of this time in a Perchlroate cell.
Good enoug for a coat between LD and Ti? I will be hopeing so.
Regarding Tin compound for getting DTO coating on Ti, the only show in town (as far as I can see anyways) is SnCl4:5H2O . Not OTC stuff unfortunately.
How does industry manufcature SnCl4:5H2O?
It is not impossible to make SnCl4(anhydrous) at home via Tin metal + Cl gas. This has been used in one patent for an undercoat and also for a DTO
only anode.
Seasons Greetings, BTW, hic hic.
Thank goodness my stock of real wine (Absolute Ethahol) is still large
Dann2
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Rosco Bodine
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| Quote: | Originally posted by dann2
Regarding Tin compound for getting DTO coating on Ti, the only show in town (as far as I can see anyways) is SnCl4:5H2O . |
You must be kidding .
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Rosco Bodine
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pH critical for adhesion of ATO
Here is an article which supports something I have postulated , maybe "guessed"
would help explain
some of the uncertainties and varying adhesion problems
which dann2 has reported concerning the ATO on Ti experiments . The article supports my idea that the
chlorides presursor mixtures are an unstable reaction mixture , the composition of which is variable with time and pH , and there is a *narrow* window
condition where
they adhere and develop on baking to produce the desired film . Miss that target composition , which changes minute by minute for the *reaction
mixture* of precursors prepared according to the abbreviated instructions supplied by the patents .......and the mixture won't stick to the substrate
.
The test substrate was not Ti , but glass . But it is probable that the applicable film chemistry would not be improved on a less inert substrate .
Whatever condition variables would prevent the desired film formation and adhesion on the more inert substrate , would more likely be aggravated
rather than remedied by a more reactive substrate .
[Edited on 1-1-2008 by Rosco Bodine]
Attachment: TSF99.pdf (511kB)
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Rosco Bodine
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more concerning pH and substrates
The attached reference gives some more information concerning the instability of the (+IV) SnCl4 chloride precursor and pH range found to be useful
for producing adherent coatings , and this study was done
using Si wafers as the substrate .
Also described is the benefit of using a hydrophyllic material
at the interface to facilitate the deposition of the SnO2 and to enhance the quality and thickness of the film .
This precisely parallels my suggested use for the mixed valency inorganic polymers of the Pytlewski patent
US3890429 , as a wetting agent ...the first thing applied
to the Ti substrate ...regardless of whatever goes on next .
Attachment: TSF2000.pdf (382kB)
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dann2
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Hello,
(Repete post from somewhere else) but I though I would stick this in here for the record.
ly got around to titrating the product from a Perchlorate cell which had the DTO anode running in it.
This cell had been run for much much more than the run time of the cell (going from Chlorate to Perchlorate).
The cell product contains 79% Chlorate.
You also get ignition when the product is mixed with sugar and a drop of Sulphuric applied.
DTO is a hopeless anode for Perchlorate making.
Dann2
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Rosco Bodine
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Just to be clear you mean not DTO in general ,
but specifically ATO ( Sb doped SnO2 ) that is not
efficient enough as a working coating for a perchlorate
anode , though it does seem to have fair conductivity
and physical endurance in the electrolyte , when it can be gotten to stick well to the substrate . Adhesion difficulties
could make alternative dopants for SnO2 more attractive
than Sb , for intermediate layer DTO schemes .
It shouldn't be any sad farewell for the difficultly soluble
antimony dopant precursors , when readily soluble nitrates
of cobalt and perhaps other soluble nitrates as well can
produce DTO compositions which are superior in their
properties , and easier to implement .
DTO is a generic term for all doped tin oxide regardless
of the dopant(s) . DTO="doped tin oxide"
Bi doped SnO2 is looking more interesting for a working coating .
Iron doped SnO2 , or Manganese doped SnO2 are also
likely cadidates .
Did you successfully make the zirconyl nitrate ?
It could have usefulness in the same way as the TiO2
has in those tertiary SnO2 compositions .
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chloric1
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A little off topic but related: I downloaded a doc or a patent talking about doping Manganese dioxide with Vanadium in a 9:1 ratio? All that is
needed is to have manganese nitrate hexahydrate melted and add the prerequisent amount of vanadium pentoxide at around 100°C. This would be brushed
on substrate and baked very simular to what is being done in the cobalt oxide anode thread. I am intrigued to know how vanadium pentoxide acts as an
oxidation catalytist in electrochemical solution. I know with the contact process V2O5 is probably momentarily reduced to tetravalent V only to be
reoxidized by the excess oxygen needed for the reaction. I wonder if this would aid oxidizing hypochlorite generated into the chlorate or it would
just fill in crystaline gaps in the beta MnO2???
@Rosco-Vanadium Pentoxide is obviously pentavalent so it would be a good SnO2 dopant. Maybe this is helpfull or not.
Fellow molecular manipulator
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Rosco Bodine
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That sounds very familiar . I have looked at so many references I am unsure which one you are talking about .
IIRC , Lead nitrate and vanadium pentoxide can also be used as a baked coating .
That's interesting about the vanadium doping or perhaps it is a mixed oxide or spinel . There are huge numbers of combinations of these things , but
the ones we are interested in is focused on the ones that are reasonably
conductive and form at relatively low temperatures ,
and adhere well and hopefully are catalytically active while having a high oxygen overvoltage .
I have an idea that any of the metal oxides which
tend to form transiently stable peroxy compounds might
function as catalytically active materials for perchlorate anodes .....permanganic , pervanadic , perchromic
"nascent acid molecules" could form on the surface of the anode and oxidize the chlorate ion to perchlorate ion ,
being reduced back to their lower energy manganic ,
vanadic , or chromic states and getting "recharged"
oxidized once again by nascent anodic oxygen .
It would seem that such materials would also tend
to present the highest oxygen overvoltage , which
is needed to kick the chlorate up to perchlorate .
There is some support for this idea I think in the pink
permanganate tinting that is being observed in Xenoids
test cell , as permanganate is certainly present from
"escaped particles" which have loosened from the anode surface and floated away into the electrolyte .
The corresponding colorations would I expect appear
for the other peracidic , peroxidic states for chromium
and vanadium .
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dann2
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| Quote: | Originally posted by Rosco Bodine
Just to be clear you mean not DTO in general ,
but specifically ATO ( Sb doped SnO2 ) that is not
efficient enough as a working coating for a perchlorate
anode , though it does seem to have fair conductivity
and physical endurance in the electrolyte , when it can be gotten to stick well to the substrate .DTO is a generic term for all doped tin oxide
regardless
of the dopant(s) . DTO="doped tin oxide"
snip
, or Manganese doped SnO2 are also
likely cadidates .
Did you successfully make the zirconyl nitrate ?
It could have usefulness in the same way as the TiO2
has in those tertiary SnO2 compositions . |
Hello,
The initials DTO when I use them, have ALWAYS been referring to Damm Tin Oxide.
(Your right, I should call it ATO)
The only reason I started to experiment with ATO was because I need it for the LD on Ti Anode. It lasted so long in a Perchlorate cell and seemed to
make Perchlorate easily I thought it might do as an anode in it's own right.
The Zr Nitrate is (if it exists) still dissolved in a labeled jar. Since the Co anode came to nill I put it on the shelf.
Going to concentrate on the LD (on ATO or possilbe Magnetite). I need to get up off my butt.
Dann2
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Rosco Bodine
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| Quote: | Originally posted by dann2
Hello,
The initials DTO when I use them, have ALWAYS been referring to Damm Tin Oxide.
(Your right, I should call it ATO) |
Don't be discouraged , the Sb doping is from many indications is perhaps the most fickle of the candidate dopants for SnO2 in terms of getting good
dispersion and good adhesion , at least as a binary composition in the absence of some third component . Added Co , Mn or Fe might improve it and make
it more easily workable . I'd have to go back and check that , but it seems there is probably a few better alternatives to the binary ATO
composition .
| Quote: |
The only reason I started to experiment with ATO was because I need it for the LD on Ti Anode. |
Nada ! You don't need ATO , you just need a DTO
intermediate layer , and if there is a DTO which works
as good or better than ATO and serves the same purpose ,
then you are still in business .
| Quote: |
It lasted so long in a Perchlorate cell and seemed to make Perchlorate easily I thought it might do as an anode in it's own right.
|
That's what you get for thinking 
ATO just doesn't have the catalytic selectivity for making the perchlorate . Some other product(s) are being preferentially
evolved as the "work" done by the current passed .
Something else must be applied as a working coating .
| Quote: |
The Zr Nitrate is (if it exists) still dissolved in a labeled jar. Since the Co anode came to nill I put it on the shelf.
Going to concentrate on the LD (on ATO or possilbe Magnetite). I need to get up off my butt.
Dann2 |
The cobalt spinel solves the interface and adhesion problem
simultaneously , (which is no small problem) , and it is a useful dopant in mixture with SnO2 , and other materials .
It does what it does do very well , solving some problems , but it is only a component , not an anode coating complete
in itself anymore than is ATO . Anyway , trust what your experiments reveal and don't keep banging your head against that ATO "wall" ....but go
around it to something probably better in a Co spinel interface / DTO sealing layer scheme . It is there that the usefulness of the Co will become
realized . ( hopefully )
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Rosco Bodine
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By request for R.P. Wang
In response to U2U message for phase data concerning the
Sb doped SnO2 system , attached is one of several references which contain pertinent information . I will have to go back and look for the others but
there are a few more .
IIRC there has been a range of figures reported for the
dopant saturation limit which seems to vary according to the method of preparation and precursors , the more complete
the dispersion of smaller particles in advance of sintering ,
the more complete is the diffusion after sintering , allowing
up to 8% Sb in the best conditions at saturation and threshold for lattice rupture .
IIRC the range seems to be from 3 to 8% and this article
putting saturation at 5% Sb is about the average of the
different sources , after *dismissing* as impossible some
patent references which suggest figures like 16% which
is simply at odds with every more extensive study results .
Attachment: Electroless deposition of SnO2 and Antimony doped SnO2 films .pdf (505kB)
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dann2
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Hello,
What patents would they be now??
Obviously not the Diamond Shamrock one's, they are up at 25%
Are we talking about best % for bare ATO anodes or when using ATO AS an interface between Ti and LD.
Perhaps we are getting hung up on %. It may not be that important. Anywhere from 0% (residual Chloride being the dopant) to 26% SB is acceptable (for
an interface coating anyways).
Least 'rupture %' may not corrospond to best anode material. It is a rather big assumption/extrapolation to make.
Quite frankly ((Madam ), I must admit,) I don't have a clue!!
Cheers,
Dann2
[Edited on 13-3-2008 by dann2]
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Rosco Bodine
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Really I am not emotionally involved with any dopant in particular or any particular percentage as I know it's likely
that a mixture of two or three may turn out to be the best
scheme anyway . Antimony loads up SnO2 more quickly than does Manganese or Iron or Cobalt , and by implication from the little there is concerning
Bismuth ,
Antimony works a lot the same way only the Bismuth
has a better catalytic effect for perchlorate . What the antimony seems to do best is in small amounts , even
fractions of 1% , it greatly reduces the grain structure
after sintering . So in that regard I see the Antimony
as being useful but for different reasons and in different
percentage , much lower percentage , where its value
is physical toughening , and better electrical conductivity , and raising oxygen overvoltage being more useful than as any catalyst . So Antimony
hardens and densifies the SnO2 and does other good things , but only to a point ,
and since it can't do it all , it needs to be part of a larger scheme where other dopants add their contribution ,
like cobalt giving chlorine selectivity , and bismuth being catalytic for perchlorate , while manganese seems to
be almost a neutral O2 selective conductive SnO2 diluent and dopant which is basically aligning with the SnO2 as a cosolvent oxide , a trisolvent
oxide effect actually with the cobalt spinel if all three are present .
Antimony seems to have a hardening effect on the mixed oxides similarly as it would for the metal alloys , like a
small percentage of silver added to tin , or a small percentage of antimony added to lead . A small amount is
very beneficial , but then above a limit it trashes the same grain as it greatly improved at a lesser percentage .
Antimony is like a strong spice , a little is good , but a
lot tends to overwhelm the recipe ....sort of like tarragon
in a stew .
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R.P.Wang
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| Quote: | Originally posted by Rosco Bodine
In response to U2U message for phase data concerning the
Sb doped SnO2 system , attached is one of several references which contain pertinent information . I will have to go back and look for the others but
there are a few more .
IIRC there has been a range of figures reported for the
dopant saturation limit which seems to vary according to the method of preparation and precursors , the more complete
the dispersion of smaller particles in advance of sintering ,
the more complete is the diffusion after sintering , allowing
up to 8% Sb in the best conditions at saturation and threshold for lattice rupture .
IIRC the range seems to be from 3 to 8% and this article
putting saturation at 5% Sb is about the average of the
different sources , after *dismissing* as impossible some
patent references which suggest figures like 16% which
is simply at odds with every more extensive study results . |
About the optimum doping content of Sb, different methods have different data, most are ranges from 1%To 10%, this ratio are most based on the best
conductivity and structure stability! If you use Sb-SnO2 anode in electrochemistry, the service life of anode is not only related to the Sb content. I
will attach this file, see the conclution of this file.
Attachment: Preparation and Characterization of Antimony-Doped Tin Dioxide Electrodes. Part 1. Electrochemical Characterization.pdf (313kB)
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dann2
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Hello Folks,
See attached:
Performance Comparison of Tin Oxide Anodes to Commercially Available Dimensionally Stable Anodes.
The study is in relation to treating waste water and pollutants.
Dann2
Attachment: Comparison of Tin Oxide to MMO.pdf (526kB)
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dann2
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Bump,
Paper here on an SnO2 Anode using SnCl2 (as opposed to using SnCl4
Attachment: 2008704+++++++++++++.pdf (502kB)
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