First LD Anode use

Rather than continue the Bucket Cell Adapter thread on this page, I hope you guys don't mind a separate thread because this is going in a new direction... the hardware will be used to test the anode I created in January using the vibrational/rotational LD plating bath rig.

I plan on creating a small perchlorate tank using a transparent food container and the Bucket Cell Adapter (BCA) hardware. Normally I would advocate that a transparent tank is not necessary for most home electrolysis efforts, and I stand behind that in general, but for the first runs with this anode, I need to be able to see what is going on. I am going to make a special trip to a store that offers high-end food containers today, and set it all up with the BCA hardware. For reference purposes, I also wanted to take a few microscopy photographs that show the velvety, crystalline surface of anode #2, now called LDA2.

It's hard to take nice pictures. I have an excellent Meiji binocular microscope that is a joy to use, and every time I look through it, the image is 3D and quite breathtaking. I've tried eyepiece cameras, but the cheaper varietites do not work well, and the best pics come from a good digital camera focused through the eyepiece; plus, a bit of editing, mostly cropping the black surrounding area.



The edges of the MMO anode gathered more LD than the remainder, creating warts and bulbs that are not pretty, but in reality, they will help structurally. The fact that they grew together tells me that the possibility of electrolyte leaching under an LD edge is minimized.

Under the microscope:


And getting closer and closer:





The odd little fibers are actually cotton or paper towel fibers gathered by the anode. On a microscopic level, the anode is like velcro or sandpaper, and in fact the surface feels exactly like 400 wet/dry silicon-carbide paper. Over the months, it has collected these little fibers that are invisible to the naked eye, but show up under the microscope.

The color is not reproduced well. These pictures appear silvery, but that is due to the reflected powerful lighting used to create the photographs. The actual color is an odd gray/black that changes color based upon the angle and amount of lighting. Under higher power, you can see the individual LD crystals themselves on the surface of the anode. The anode weighs exactly 197.00 grams. After use, a further weighing should revel erosion, if any.

The next step (today) is adaptation of the bucket cell hardware to a "Click-clack" food container of approximately 4 liters. More to come!

Quote: Originally posted by Swede

I plan on creating a small perchlorate tank using a transparent food container and the Bucket Cell Adapter (BCA) hardware.

I just realized the title of this thread is deceptive, as if it's already in use... sorry about that.

@ Pat: From the beginning, I decided I wanted to execute a two-step process - harvesting, washing, drying, and stockpiling chlorate for later conversion to perchlorate. The Chloride to perchlorate process is possible, and LD should do it, but by going two-step, I can keep the product a bit purer, and in the end, what falls out of solution should be pretty clean KClO4 due to its horrible solubility. Both chloride and chlorate should remain behind. So this cell will start with raw (not recrystallized) potassium chlorate at an elevated temperature. I plan on preparing the solution at about 50 degrees C to dissolve as much as possible, quickly assemble the system, and hit it with current to keep the temperature up and avoid premature crystallization of chlorate by early cooling of the liquor.

The starting chloride will be residual and probably less than 1% of the solid, and perhaps less than 1/2% by weight in solution. If it turns out that recrystallization of the chlorate is required prior to further electrolysis to perchlorate, then some rethinking (for me at least) may be in order. LD is supposedly rugged and should handle a bit of chloride. We'll see.

The bucket cell hardware was engineered to take the LD anode, back when I was making electrodes with 3/4" wide straps rather than 1". It will not be able to carry the same current as the larger strap, but should do the job.

@Hissingnoise: The clear container I've used in the past (successfully) with Pt anodes is some type of polycarbonate, and survived the process with little fuss. Overall, perchlorate seems far more benign than Cl- --> ClO3. The theoretical yield per coulomb is higher, and the overall transformation generally faster at a given current. If I can get 1 or 2 runs, that will be adequate. But I do want to see if the anode is shedding or suffering physically.

Of the two LD anodes I made, LDA1 was a POS and mechanically is falling apart in its storage bag, with flakes of LD at the bottom. I doubt its ability to do a decent job. Maybe later. LDA2 is the one pictured.

@ WF: I can't wait or delay any longer. Future Bucket Cell Adapter #2 will be a deluxe variant, but I need to give this one a shot. Earlier, a liquid level sight glass, made from an old pipette, clogged hopelessly in a previous chlorate run. To correct this flawed methodology, the new system consists of a cut and flame polished medium-bore pipette section that slips into a teflon fitting at the top of the cell. To measure the liquid level, a finger is placed over the pipette, and the pipette pulled from the fitting, retaining the liquid. The natural volume marks on the pipette will let me know where the upper liquid level is, and this sort of system will not clog compared to an external sight glass.

The use of Pt generally creates an interesting ozone smell, and I am curious to see if LD behaves similarly. dann2, did you ever notice an O3 odor with lead dioxide?

I have 3 continuous work days starting today. I hope to have the cell running on Monday or Tuesday, 7 or 8 Dec.

Karma appreciated. If it works, I am going to set the LD plating rig back up and try making a few LD anodes, testing to see if a lighter plating will do the job. Not a flash of LD, but not necessarily a 1/4" or 6mm thick plate either.

I forgot to mention, it will be interesting to see how the LD deposited over pure titanium will behave. In this picture, the flat section at the lower left is the welded continuation of the anode strap, and is not MMO coated, but plain CP titanium. Before plating, it saw the same degrease/surfactant soak that the rest of the anode did. I plan on submerging it fully, and if the plain LD over Ti survives and contributes to the reaction, then the process to plate the anode may apply to CP Ti tube or similar, and may not be limited to MMO.

The MMO was brand new deNora MMO mesh, not the Laserred stuff.

Quote: Originally posted by Swede

Future Bucket Cell Adapter #2 will be a deluxe variant, but I need to give this one a shot. Earlier, a liquid level sight glass, made from an old pipette, clogged hopelessly in a previous chlorate run.

Hello,

I have noticed Ozone from LD Perchlorate cells as they come to the end of the run. LD has been used for Ozone production.

About the bare Ti that has been plated. It will be difficult to know what exactly is going on with it (if using that part of the device as active Anode area in solution) as it may well be supplied with current from the LD on the MMO mesh if indeed the bare Ti passivates under the LD. I am presuming there is a bit of an overlap between LD deposited on the MMO and the LD deposited on the bare Ti to allow this. None of the pictures show an angle where you can see it well enough. A picture from the bottom of the Anode would.
I have always noticed it is impossible to get LD to plate into inner corners (like the corner where the bare Ti edges meets the MMO mesh). It loves to plate onto outside corners, hence all the nobbly bits, warts etc.
I do not think the LD will flake off the bare Ti but it is probably not as well bound to the Ti as to the mesh simply because of the physical nature of the mesh/LD as opposed to flat-surface/LD (apart from the MMO coat which may help adhesion too).

Dunk the whole shaboo (MMO part, Ti/LD part and some of the Ti shaft) into the cell and see how it goes.
Regarding thickness of coating, LD Anodes do wear. The commerical Graphite substrate had 6mm (AFAICR) and lasted on average two years. With Ti the same thickness will last far longer because if the Anode develops an LD fault the Anode substrate will not start to fall apart but will continue to operate untill most of the LD is gone.
Thick coats good, thin coats bad.
Thick coats good, thin coats bad.
Thick coats good, thin coats bad.

A transparent cell is good but you can never see as much as you hoped because of all the fine bubble in the cell. It's like trying to see through dense mist. Putting a light behind the cell can help.
A demijohn (wine making yoke with two eye handle a the top) makes a great cell. Score a line around the jar close to the top and you can break off the top using a hot wire. Use a sharpening stone to smooth off the sharp edge.
You get a nice glass funnell too, with handles on the bottom!

Consider weighing the Anode after is has operated for (say) one hour. It will be soaked with solution at that stage and will be a better starting figure to go on. If you compare future weighings (a few days) to the dry weight you may find the Anode has increased! in weight (due to solution, unless you wash and dry it).

Are you using one or two Cathodes?
It will be interesting to see if the K Perchlorate will stick to the LD Anode as it is formed. It did not with the Pt but it's much smoother. Hopefully it will not or if it does it can be wiped off easily and not interfer with cell operation.



Good luck,
Dann2

The small test cell is completed. I didn't realize initially how small my LD anode really is. It measures 8.9 X 4.6 cm, with a basic surface area of 0.41 dm^2. Given the convolutions, the surface as viewed under a microscope, and the mesh configuration, I am taking a wild guess and multiplying this by 2.4 to determine the functional surface area. A major MMO manufacturer told me that their MMO mesh was 2.2 times the basic dimensions.

This yields a surface area of 98.4 cm^2 or 0.984 dm^2. I'm going to call it 1.0 dm^2 for purposes of current. Literature yields a range of 15 to 35 amps per dm^2, and my thoughts are 20 amps is a good starting point, which can be altered depending upon temperature, with 60 degrees being an upper limit. The fairly small Ti strap is going to limit the current anyhow - this anode was made when my understanding of the limitations of titanium as a conductor was not as good as it is now, and the strap is too small.

The cathode is titanium, and fairly small, yielding a higher current density at the cathode. For the first run, at least, I am not going to add NaF or any other sort of additive. I want to see what sort of CE I can get in the native state.

The only other change I made was the use of viton gasket rather than skived PTFE gasket, with the hope that it will reduce the inevitable salt creep.

Tomorrow, I will mix up the chlorate and power it up.

Quote: Originally posted by Swede

I agree, there are cases where an attachable sight glass would be a real advantage. I wonder if polycarbonate would do the job without fogging badly? Glass would work if drilled with diamond drills, but the mechanical challenge with glass is high.

After the preliminary microscopy photos, which will help me create some baseline images of the pristine anode surface, it was time (finally!) to actually power the darned thing, and make some perchlorate with it.

For this test, I have gone back to a clear polycarbonate food container, brand name "Click-clack", for the first run, and it has a capacity of approximately 4 liters. The transparency was desirable so I could see how the anode is doing physically.



The liquor was prepared by heating 4 liters of tap water to 50 degrees, and dissolving 600 grams of potassium chlorate, the raw product from previous runs.

The small test cell was wired appropriately to my data-collection rig:



and my small notebook PC (using an 8 gig flash thumb drive) was fired up, using the DATAQ software for data collection of voltage, temperature, and current.

Right away, I noticed that the bucket cell hardware was definitely not optimized for an LD anode. In my bucket cell adapter, I had spaced the electrodes by 1 inch or 25 mm (don't ask me why I did this) and the voltage required to obtain a decent current (17 amps) was quite high at about 8.5 V. I also used a small cathode which made the problem worse. If I had two cathodes, and correct spacing, the voltage would be probably around 6.5V.

The temperature of the liquor at the start of the run was 50 degrees C, and is climbing slightly, a good sign, since it is easier to cool a cell than to keep it warm. 20 amps was my target, but 20 amps was pushing the voltage limits on my power supply, so I decided to keep it at 17.





With the data collection at work, I should have a good feeling for the efficiency of the cell. So far, all appears normal. Plenty of hydrogen evolution, and best of all, I am noticing a distinct odor of ozone, exactly the same as when Platinum is used.

I expect to see some solid perchlorate forming in a day or two. So far, everything looks excellent. More photos and text on my Lead Dioxide Anode blog for those interested.


[Edited on 8-12-2009 by Swede]

Report, day 2: Good news - Perchlorate is accumulating. Bad news - about 5 of the bulbous nodules on one side have fallen off the anode. Damn. I'm wondering if I didn't sabotage myself with too high a voltage and not enough cathode area.

The edges of the underlying MMO anode were bare titanium due to saw-cutting of the original MMO material. If there is a consistent degradation of the LD over bare Ti, but good adhesion on the MMO, then that would be a good clue.

I have dialed the amperage down to 10 amps to reduce the voltage.

I am disappointed, but the bulk of the anode is soldiering on, it is just about 5 separate warts that have parted company... but that is a bad sign that the overall anode integrity is not as strong as I'd hoped.

Thoughts - A cylindrical form for the LD would probably produce fewer weak areas for this sort of failure. Surrounded by a larger tubular cathode, you'd have a very even current distribution, and perhaps less erosion, but then you're back to the original problem of plating bare titanium, unless you can obtain a cylindrical MMO anode to plate.

It's probably time to break out the plating rig again... argh, I hate plating LD, it gives me the creeps. But this time, I'll not stop with just one, which was stupid. While the bath and rig are set up, it'd be best to plate several different forms if the bath can support it.

I don't want to overemphasize failure, it's just 4 or 5 edge warts, but I was hoping it would come through without any mechanical failure at all.

Another problem - the mesh holes in the LD are PACKED with crystalline perchlorate, and the surface of the anode is dusted with it. I attempted to position the bubbler to kick these crystals off... we'll see. It may be physically difficult to make potassium (as opposed to Na) perchlorate directly with LD.

Sodium would not have this particular issue. I don't know what effect it (the coating/dusting) might have, but it can't be good. If the coated areas of the anode no longer conduct, then the efficiency will slowly drop to nil. On the other hand, what might be happening is that the perc forms on the surface, builds to a certain mass, then drops off, exposing LD for additional conversion. The dusting of perc at the bottom of the tank would indicate that there is a successful conversion.

We'll see.

Added: I'm already thinking about a new form of anode that should avoid edge erosion issues. Take a look at this picture from Titan:



Note that the periphery of the anode has a strip formed around it. Picture a primarily MMO substrate with strips of CP titanium welded onto it to form a sort of frame. In a LD bath, if the anode is rotated, you are going to get some LD deposition on the framing strip, but it probably will not adhere well at all, as the Ti oxides would form almost instantly. After removal from the LD plating bath, the frame is intentionally scraped clean of all LD. What you end up with is a solid, well-secured, conductive LD mass within the frame, supported structurally by the MMO and the surrounding frame, hopefully keeping edge erosion to a minimum.


[Edited on 9-12-2009 by Swede]

Some good news... Around 12:00 noon, I decided to replace the dinky cathode with something better, a box cathode:



Part of the problem was that I had selected a very small cathode, as supposedly, the current density on the cathode should be high for best efficiency. But the voltage was too high.

The anode was also gathering significant amounts of crystalline perchlorate on the surface. Interestingly, the side of the anode AWAY from the cathode was the one gathering crystals... the side facing the cathode was clean. I decided to replace the dinky cathode with the box, and while the system was down, I could also take a look at the anode and try to find out what was going on with it, mechanically.

After this was made, the test cell was taken apart, temporarily. This is the anode inside the cell, away from the cathode. Note the loss of several of the edge "warts" on the left side, and the accumulation of perchlorate crystals:







The anode was removed, washed in warm water, and then I gently manipulated the remaining warts to see if they were adhering well. The warts on the bottom were quite strong. Those on the sides popped free easily. I decided to go ahead and remove all of the side warts, and it didn't take long.



The good news - wherever the LD had adhered to MMO, which included the faces of the anode, and the bottom edge, the adhesion was very strong. I tried about 3X the manipulation on the bottom warts, which had an MMO edge (as opposed to a sawcut edge) and they didn't budge, so I left them there. The system was reassembled with the box cathode:



With the power applied, I was very happy to see the voltage drop by about 1.5V for a given amperage. Right now, I am at 15 amps and 7.0V, and this would be 5.5V to 6.0V if the spacing was better. The perchlorate is accumulating rapidly.



The anode in its current state wasn't what I started with, but at least I verified one thing - the lead dioxide plated over the MMO areas yielded a strong adhesion which is very promising. If I had popped those warts free after the anode had been initially plated, it'd look as it does now. A bit neutered, but what remains appears strong and functional.

So the news is, I'd say, about 75% good, and 25% bad. Properly prepared, it appears that LD does in fact plate over MMO very effectively. The real test will come in a day or four. If there is no additional erosion at the edges, where the warts were popped free, then I'd say I have a smaller, but strong and functional LD anode.

Hello,

O deary me. I am putting ashes on my noggen as I type.............
I would not be inclined to worry about a few warts falling off. In fact it will make the Anode less ugly , a form of beauty treatment for Anodes.
A piece of the MMO/Ti is now exposed to the solution, so it will be interesting to see if that part of the Anode falls apart. I don't believe it will.
LD (as we have said before) simply loves to plate onto sharp corners and edges. This is why it was important to round off those
large Graphite substrate Anodes used in Nevada way back. The current density in the plating bath is higher at sharp corners
which gives a greater plating depth. I guess that when the warts get to a very large size (large radius of curvature) then the plating onto them will start to approach a rate similar to flat area.

You could also put plastic pieces instead of CP Ti, and remove them when Anode has plated or perhaps put wax/hotmelt/tape etc onto the ends/edges to stop the warts etc. Baffels were sometimes used in LD plating tanks to get less LD to plate onto areas of Anodes (like at edges). The baffle was simple a piece of non conductor hung close to where less LD was wanted. It forces current to travel a longer path for to get to that place.


Going back to making Chlorate with Graphite. The erosion mechanism for the Graphite was thought to be both chemical and physical. (pH controlled, commercial cells). The physical erosion came about by solid Chlorate forming inside small pours of the Graphite, expanding (crystals growing I guess) and heaving out small lumps of Graphite. This is why it is important to seal up porous Graphite with Linseed oil (etc) so that this would not happen much. Perhaps a similar thing will occur with the LD and K Perchlorate if solid K Perchlorate starts building up on/in the Anode. Never heard of it mentioned with Sodium Perchlorate manufacture using LD. Hopefully this phenomen won't occur.

Just seen your last post. Consider putting plastic around the outside of the Cathode (where you do not want any Cathode really) to keep down surface area. It is a very large Cathode (even larger of you add in outside surface). CD will be very low on outside. Then again Ti Cathodes are not supposed to reduce Chlorate to Chloride much (I think). Not too sure about how good it is at reducing Perchlorate to Chlorate. Will look it up (if I can find it). Perhaps it's my small Cathode fettish.............

Perhaps there was more gassing (higher CD) on the Anode side close to the Cathode giving more stirring and less K Perk. deposition??

Remember too that the warts that fell off easily would have gone onto Ti that was not even etched. It would have had Ti Oxide on it before you started to plate. The acid bath would surly have manufactured more Ti Oxide as plating started. If using bare Ti you absolutely need to start with a neutral/close to neutral Nitrate bath, or better still a Tartrate bath.
Just realized the bare Ti strap plated OK!!!!!!!! though.

Great pictures etc (as per usual).

How's the pH?

Dann2


[Edited on 9-12-2009 by dann2]

[Edited on 9-12-2009 by dann2]

Quote: Originally posted by Swede

dann2, I have noticed very little variation in CE with Ti cathode size, at least with chlorate and MMO. It doesn't seem to care if if the cathode current density is very low, or very high. I don't know if this also holds true with perchlorate and LD. The pH peaked at 10.5 and normally hovered around 10.0. As usual, the perchlorate cell was cleaner, less fussy, less salty, and better-behaved than a chlorate cell. Future LD plating attempts will focus on surfaces without sharp angles, if possible. Failing that, then I am going to try a "framed" MMO mesh. ..............

I've been at "real" work for a couple of days. This afternoon, I will take the system down further, free the anode, and look closely for lead on the cathode, and what type of erosion (if any) I see on the edge of the anode.

I hate to keep beating this drum, but everything I've seen says that without exotic surface prep, bare Ti will not take a good LD plate, but the MMO does. When the factories make MMO mesh, they apply their "trade secret" Ti surface prep prior to dipping and baking the powdered MMO slurry, or however they do it. I say we take advantage of their hard work, and with the availability of surplus MMO at inexpensive prices, use that as the substrate for plating.

If examination (and further runs) show no additional LD erosion at the edges, then a frame may not be needed. Simply execute a decent plate job on a cut and prepped MMO mesh, and if you feel the need (I do now!) pop the edge warts free and grind them up and save as a reasonably clean source of LD on a small scale for other applications. What remains is a well plated and attractive LD anode.

Hello,

@12AX7 Did you use the same huge Cathode when running the Perchlorate cell or was it the home plated Pt on Ti that you are referring to?

Perhaps Persulphate should be seen as the Green Mans Cell Additive. (AKA GMCA). Dichromate is out for LD, it's also nasty, Flourides are out (IMO) for Ti substrate anything as it seems to erode Ti (toxic too).
Don't know how Persulphate fits (or dos'nt) into pyro stuff though.

"I've been at "real" work for a couple of days."

Great! So what exactly were you mixing with the Perchlorate for the couple of days................

I would be inclined to agree that bare Ti will not work. Quite alot of the Anodes that had LD put onto bare Ti were used for electrowinning and often where a (bare)Valve metal was coated with LD the long term electrical connection was made directly (using Silver paint) to the LD. ie. a massive Anode.
Tin Oxide on Ti(my hobby horse). Easy enough to actually do and cheap but SnCl4 is not easy to obtain.
MMO on Ti is the business (so long as you can get it).
Perhaps a single coat of Manganese Dioxide or Cobalt Oxide on Ti would solve the Ti Oxide problem. Never seen it mentioned by any reputable source though. These coats are easy enough to do and materials can be had easily and cheaply.
Ebonex (an Oxide of Ti) on Ti works too I believe, but Ebonex is not easy to form on Ti.

Conversion of ground up Lead Dioxide warts for inclusion into Dragons eggs can only be a good thing.

Dann2

Quote: Originally posted by dann2

I do not believe the undercoating (first coat on Ti) of Cobalt Oxide in necessary or an advantage. Dann2

So there you have it, just disregard all the useless research about needing a conductively doped anti-passivation interface for the Ti used as an anode substrate, as there are no problems there which may arise And all that data about needing also some sort of anodically conductive ionic oxygen barrier, most economically achievable by using a bismuth doped tin oxide, well that's probably all nonsense too.

I have a furnace, good instrumentation, and some materials to test out all that possibly irrelevant theory if I can ever
get the time to confirm those wild ideas. I can't really take the credit for inventing those ideas, since they were ideas derived from exhaustive search of the available literature.
Oh well, time will tell. I'll have to get back to you with any experimental results if and when.

Has anyone chemically tested the MMO mesh to see if it is possibly an IrO2/Ta2O5 coating ?


Whatever it is, it might be good for perchlorate with an added baked coating of a few coats of Bi doped SnO2, derived from the 100% hydrolysed PVA thickened ammonium bismuthate / ammonium stannate precursor hydrosol.

Alpha PbO2 may possibly also be workable as a working perchlorate anode coating applied directly to the MMO mesh and the Alpha PbO2 should be even more adherent and make a finer grain and more dense coating, requiring no use of surfactants as some of the Beta PbO2 processes.

I like the idea of coaxial electrodes having a pumped flow electrolyte, like the California surfers would say ......
totally tubular

http://www.telprocompanies.com/tubular.html

Some interesting rod anodes are available also.


[Edited on 15-12-2009 by Rosco Bodine]

RB, I do not have your knowledge. But I have a lot of crap... Titanium, niobium, bismuth salts, boehmite, a few manganese and tin salts, and an extremely accurate computer-controlled furnace, 100C to >1,000 C. Every Pb salt known to man (almost). Most other essential lab chemicals. Two hands.

What do you have in mind? I'll try it. You just have to translate it into college freshman chemistry language.

The MMO mesh I have (both varieties) are Ruthenium-based. I can verify one of the two types by contacting the manufacturer, but I am 98% sure it is Ruthenium rather than iridium or tantalum. Their performance in a chlorate cell is unquestionable. The LD plated MMO was new MMO and not the eBay surplus material.

Dann2, I'm not sure how to solve the edge wart problem. Most MMO sheets are cut and have a bare Ti edge. These warts were about 6mm in diameter and appeared very solid. I thought that the barrier created, and the mechanical connection to the remainder of the LD coat, would have ensured their strength. Apparently not.

Perhaps: During the LD plating, at the 80% complete point, pull the anode and pop the edge warts free. Re-immerse the anode and plate additionally so as to seal the fractures with another layer of LD. Or perhaps an edge coating of some sort of sealant or polymer? I don't know.

Hello,

That's the advantage with Titanium substrate Anodes. The warts are NOT a serious problem. Simply go on using the Anode. I do not believe that the small amount of exposed Ti at the edges of the Anode will have any bearing on the life of the Anode worth talking about. The only issues are cosmetic and the fact that it wastes some Lead Nitrate (and generates more acid in plating tank etc). A simple baffle (plastic or welded Ti or even blobs of hotmelt) will get rid of the problem if you so wish. If some exposed Ti was going to cause destruction of the Anode then we might as well go back to doing Graphite substrate stuff

Regarding the color of the LaserRed MMO. It is black. I purchased some MMO wire (Ti with Copper up the middle) used for corrosion contol approx. 10 years ago. It had a black coating on it and it was stated by the makers that it had an Iridium Oxide outside coating. It seemed to have an undercoating of MMO (of some sort) as when the black coating wore off, gassing was still taking place on the Anode surface. I tried making Perchlorate with the stuff. Let it run for approx. one week. No Perchlorate.

Dann2

Quote: Originally posted by Swede

RB, I do not have your knowledge. But I have a lot of crap... Titanium, niobium, bismuth salts, boehmite, a few manganese and tin salts, and an extremely accurate computer-controlled furnace, 100C to >1,000 C. Every Pb salt known to man (almost). Most other essential lab chemicals. Two hands. What do you have in mind? I'll try it. You just have to translate it into college freshman chemistry language.

RB, I didn't mean for you to go to all that trouble, but I do appreciate it. Thank you.

In my very first LD plating effort, I made use of a number of patents that use Bi as part of the process, and it seemed to give me a lot of grief in creating an even, fine-grained coating. I know that has nothing to do with what you refer to, but it made me suspicious of Bi in an irrational way. I am going to spend some significant time and look at alternate anode methodologies. The sheer volume on this board is intimidating, and sometimes ideas tend to merge with others.

My limited understanding is that primarily Ru-based MMO is optimum for chlorate, and that Ta and Ir are used in varying proportions more for cathodic protection, corrosion control, etc. The laserred material is black, once the brown smut is cleaned off, and I have seen it shrug off extreme conditions without any sort of failure. Whatever the proportions of oxides, it is an excellent chlorate producer, and with even crude pH control, CE's at ~90% have been demonstrated. I too tried making perchlorate with it, and while it suffered no damage, all I got after a lengthy period were aqueous traces of perchlorate. If there is an efficiency, it cannot be much above 1 or 3% and not practical. Interestingly, the smells generated were lacking the O3 whiff that I have distinctly noticed with both Pt and LD.

I know the O3 smell is not scientific or conclusive, but it is something I have consistently observed in successful perc cells. It even led me to attempt bubbling ozone through saturated chlorate solution, and traces of perc were definitely made, but very, very slowly.

Anyway, plenty of lessons learned. I recrystallized the perc produced by the LD anode, and it required two hot filterings to clean the blackened product. It is at 0 C right now and the crystals are lovely. But it was a PITA compared to a Pt batch.

Two prime objections to Pt... initial high cost, and Pt erosion. I know this has been discussed before, but I wonder if a flash of LD over Pt would adhere well, protect the Pt, while simultaneously having a substrate that will not passivate and become non-conductive.

Quote: Originally posted by Swede

I was curious at to what the grain structure would look like.