The etched Ti was then coated with 9 coats (9 bakes) of ATO using a standard ATO precursor solution of SnCl4:5H2O + Sb Trichloride + HCl + Alcohol. The ATO solution was made up of: 30 ml Alcohol (distilled Methylated Spirits was used) 5 ml 33% HCl (or 8ml 20% HCl) 15 grams SnCl4:5H2O 5.3 grams Sb Trichloride solution (homemade SbCl3 solution containing 31.8% Sb) (25% Sb in ATO precursor as per the DS Patents) The Alcohol and HCl should be mixed first. The Sb Trichloride was made from Sb Trioxide as described elsewhere on this page. The ATO solution was brushed on to the Ti and the Ti let drip dry by hanging for five minutes or so. The Ti was then given a good shake or sharp knock(s) on a clean surface to get rid of excess solution. The Ti was then dried using a heat gun. It is important to keep the Ti moving when drying, to stop the ATO precursor from forming puddles. Another coat of ATO precursor was put on as before and dried using the heat gun. This was done a third time. The Ti was then baked at 480C to 490C for approx. seven minutes. This was repeated a further 8 times. When the 9 coats were finished the anode was given a final bake at 490C for one hour. The substrate had now received a total of 9 bakes, 3 coats per bake. The Ti had now a black/blue coating that looked like cracked mud under 100X magnification. A bright purple color indicated where ATO has not been applied successfully. Some parts showing this color will be inevitable. If this was a first attempt at applying an ATO coating to Ti it would be prudent to test the coating to see if it has been applied successfully.

Note that half of the yellow tape shown in the picture was removed prior to coating with LD. It was put there during previous (unsuccessful) attempts at coating Alpha LD using a Na Plumbate bath. This is also why the substrate looks brown as opposed to blueish.

A coating of Alpha Lead Dioxide was now applied by using a Lead Tartrate bath. The Lead Tartrate bath was made up from:

• 100 grams Potassium Sodium Tartrate
• 50 grams Sodium Hydroxide
• 96 grams Lead Oxide (Litharge)

Dissolved in the order listed into 2 liters of water. The bath was heated to 60C to dissolve all Litharge. Any Litharge that did not dissolve was then filterer (or decanted) off. The Litharge was ground with a pestle and mortar to get rid of the lumps that were in it before adding to bath.
The actual bath size used for the anode plating was 600ml. The bath was used at 70C with a current density on the anode of 1.2mA per square cm. Gentle stirring was used. The tank had to be topped up with water on a regular basis as the level dropped due to evaporation. Ti cathodes (two) were used. The ATO coated Ti was plated for 22 hours to give a thin coat of black Alpha LD. This coat, when viewed at 100X appeared as a mass of nodules not unlike looking at blackberries. The anode at this stage weighed 22 grams and was 3.0 to 3.1mm thick and 9.8cm (active area) long (other dimension not measured).

• 450 grams Lead Nitrate
• 6 grams Copper Nitrate
• Nitric acid to put pH to approx. one (a few ml's of 60%)
All dissolved in 1 liter of water
The actual bath size used was 800ml. Plating current was a steady 315mA. A current density of approx. 15mA per square cm on the ATO'ed Ti was used at the start. At the end of plating, due to the increased size of anode, the current density was 7.7mA per square cm. The temperature was 55C. Stirring was used with approx. 12 grams of Aluminium Oxide grit (abrasive grit, sieve size 300 to 400) added in order to keep any bubbles that formed on the anode wiped off. A quantity of this grit actually got incorporated into the coating.

Some Notes on making the anode:
Set up you bath first using water to see if stirring will successfully keep ceramic particles in suspension.
Use a larger size of grit to help stop it being incorporated into coating. A less dense grit may be needed if this is done.
The bath must be deep enough to accommodate the anode and cathodes + allow room for stirring bar (if using a magnetic stirrer).
Keep additions of water as small as possible to keep bath temp. steady or better to add water preheated to the bath temperature.
Evaporation from Alpha bath can be bothersome. Floating some plastic material (Polystyrene?) on the surface may help to slow it down.
Keep an eye on Lead deposition on cathodes in Beta bath. If it should start add more Copper Nitrate. Using Copper cathodes will also cure the problem.
Connect both cathodes to power source.
A thicker coating of Lead Dioxide than above should be used.
A larger plating current density should be used.
A bigger bath and/or addition of Lead Compound should be used. The Nitric acid formed when the 31 grams of Lead Dioxide was deposited was equal to 16.34 grams. This represents an acid concentration increase of 20.42 grams per liter (800ml tank used) which gives a total acid concentration of approx. 24 grams per liter at the end of the plating session. This is too high. The 31 grams of LD deposited represents a plating current efficiency of 63%. The acid concentration may have been higher than the 24 grams per liter as Nitrites being oxidized at the Anode causes more acid to form.

Using the anode

First 'Holy Grail' cell run

The Anode was used in a Na (Per)Chlorate cell that was let run from Chloride all the way to Perchlorate with no pH control. The cell was 2.25 liters containing saturated salt solution, approximately 760 grams or 13 moles NaCl. NaF (4.2g) and Sodium Persulphate (4.2g) was added to the cell. Anode current density was from 200 to 300mA per square cm with an average current into cell of 9.5 amps. Cathodes were Titanium. The Chlorate conversion current efficiency (when Chloride concentration was high) was poor at 20%. The temperature was in the region of 52C. Lowering the temperature to 32C helped somewhat, CE increased to 26%. Lowering the current density to 100mA per square cm (4 amps) did not help, in fact the CE decreased further. The cell was run for 10 weeks using the 5V output of a computer power supply with the cell at approx. 40C. A resistor was used at the start of the cell run to keep current at around 10 amps as it was inclined to get high. The Chlorate level at the end of the run was very low at less that a few grams per liter and the Chloride level was approx. 6 grams per liter. A quantity of Lead (I presume) collected on the cathodes and had to be removed during weeks 7/8, see picture. This Lead weighed 6.7 grams when washed, dried and weighed. A total of 0.3 mm was wore off the anode surface. A quantity of brown ppt (probably Lead Dioxide) was sitting on the cell bottom with the Perchlorate containing liquid clear. The brown sediment at the cell bottom was 6.3 grams when washed, dried and weighed. Aluminum Oxide abrasive could be seen in the sediment. The Aluminium Oxide was used when the anode was being made in order to keep bubbles formed sweped off the anode. The abrasive had been incorporated into the coating as the anode plated with Lead Dioxide. The overall current efficiency for the conversion of the Chloride to Perchlorate was 17% (industry gets 50% to 62% for this type of run with pH control). There was a smell of Ozone coming from the cell for the last 3 or 4 weeks of its run. Cathode area was large. The backs of the Cathodes were exposed and although the Cathodes were made from Titanium the actual active surface area of the Cathodes was Lead. This may have had an undesirable effect on CE even though additives were added to hinder reduction (conversion of Perchlorate back into Chlorate) at the Cathode.

Pure Perchlorate cell

The anode was tested in a cell for making Na Perchlorate from Na Chlorate. The cell was 880ml in volume containing 520 grams (~5 moles) Na Chlorate + approx. 17 grams Chloride as the Chlorate was home produced. Three grams NaF was added to cell. The cell was placed into a bucket containing some water to keep the temperature at 40 to 50C.
The 5v output of a computer power supply was used to drive the cell with a current of approx. 8.1 amps (average over run) going into cell. Ten Moles of electrons ( 26.8 x 10 = 268Ah) would be required to convert the 5 Moles Chlorate to Perchlorate giving the cell a run time of 33 hours @ 100% CE (current efficiency). The diagram below shows Chlorate destruction per hour.

CE on day one was 47%. The CE was strangely low on day two at 7%. Day three 16%, day four 28%. The cell was run for approx. 4 more days with a CE of approx. 7%. The final Chlorate concentration was 11 grams per liter. The pH of the cell always drifted to a value of approx. 10.8. HCl was added now and then to reduct pH to neutral but no serious attempt was made to keep pH neutral. According to studies pH is not relevant to CE, perhaps it is relevant when the concentration of Chlorate is low, which may account for the CE's obtained as a number of additions of HCl were made on day three as opposed to just one additon on day two?? According to Schumacher, 'The Perchlorates', all commercial Perchlorate cells are pH controlled at around neutral.
After 32 hours of operation a 'yougart ptt' was observed when KCl solution was added to a cell sample.
The Anode was eroded from the beginning of the run with brown LD deposited on the bottom of the cell. There was some Lead metal deposited on the Cathodes too. Anode wear was greatest at the bottom, perhaps stirring the cell would have helped. Anode wear can be seen in the picture with exposed Ti at the arrow. The exposed Ti still had a coating of Tin Oxide that was active ie. bubbles when observed coming from the Tin Oxide when the Anode was in the cell. This may have kept the CE low as Tin Oxide is a bad Perchlorate making Anode. It seems to just make Oxygen.
Cathode area was large. The backs of the Cathodes were exposed and although the Cathodes were made from Titanium the actual active surface area of the Cathodes was Lead. This may have had an undesirable effect on CE even though additives were added to hinder reduction (conversion of Perchlorate back into Chlorate) at the Cathode.

Second 'Holy Grail' cell run

Another cell run was performed with pH control, using the same Anode and Cathode set up as pictured above. No additives (NaF, Persulphate) were added to the cell. It should be noted that the Anode at this stage had approximately 50% of the Titanium substrate exposed as depicted in the picture. The Anode system still performed OK as the Titanium did not passivate under the Lead Dioxide.
The graph depicts what happened.