Platinum plated titanium

The always present dilemma... do I make a new thread or go off topic in an existing one

Already I am unhappy with my platinum electrode. It leaks from the bottom and initially released bromine into the confined space within the pipette. The platinum seems ok, but the tin/lead has gone white. It still conducts though. I have wax stuck at the bottom and that has stopped the leak for now but is slowly turning into crap in my solution, it floats at least. I'm not going to throw it out but I am looking for a new option and will decide if if needs to be resealed if and when I need pure platinum (It has been heated very hot 4 times now, and the platinum wire has gone as soft as solder). Anyhow.... about this new topic....

Recently Xenoid mentioned in the PbO2 thread that he had acquired one of these:

http://www.palloys.com.au/category7_1.htm

a platinum coated titanium anode.

Now obviously this wont stand up to as much abuse per unit area as pure Pt, but it has a lot more area.

Xenoid also mentioned that there was some corrosion starting near the edges. (@Xenoid- is that the non coated edges where they cut it off?)

I was thinking that if you got one of these it may be possible to expoxy, or otherwise seal the edges and the spot welded connection (and half of the rod). In this way it could be completely submerged and erosion would not occur.

Is this possible? More specifically, is there some hard, strong substance which is chemically unreactive which could be coated on to metal well?

I like the look of this anode on the basis that it is not as flexible or flimsy as anything else I had envisioned using. I could put it close to the cathode without fear that they would touch. Also, even if it is not as good as platinum it would still take many amp-hours to burn out.

Maybe because I have no titanium, several hundreds to a thousand dollars worth of platinum to dissolve to make a plating solution, a reliable temperature control unit to keep a constant temperature, any information of the current density, temperature, concentration or duration of electroplating, and finally I have never come close to making a cohesive coating when electroplating in the past. Just to name a few


You can bet your life it doesn't have a gram of platinum, if it did I would buy them and salvage it, making a slight profit.

This is all in AU$.... And WTF?????

Is the US sucking these days or is Australia unsucking? last time I checked it was more than AU$55/g. You are right, it is now only ~AU$47/g. And so yes I was exadurating (no I can't spell and that one is too far gone for the spellchecker) slightly before about making a profit. But as of a month ago, not by much.

I realise that the concentration of platinum must be low, but I almost certainly don't have a reaction vessel the right shape, so that means making a large excess of solution. I also will be hard pressed to weigh things that accurately when making the solution. I can always sneak into uni and use their tenth-milligram balances and as long as I only do the measuring there they wont be too pissed if I get caught. Also, don't you need a platinum anode unless you want to contaminate your solution? If you have data about this or can point me in the right direction then I will seriously consider it.

Unfortunately it is usually closely guarded trade secrets as to how to electroplate properly, my father found that out when he wanted to plate gold a decade or two ago. Fortunately we now have the internet with a good knowledge base of intelligent people (as well as oh so many more stupid ones, but we can ignore those).

Finally, pretending you don't need a platinum anode which I believe you should have, you need symmetry of anodes with respect to the cathode or it wont plate evenly. And you have trouble with large surfaces because of 'depletion' where the center of the cathode has a lower concentration because of the platinum being used up by deposition at the edges. I know the above two because my godmother's housemate is an electroplating operator, but only does silver and gold of the precious metals.

And sorry if I am waffling, I have been up for 48hrs, mostly not doing my assignment.

That is preciesly what concerned me about electroplating. A cohesive coating is very hard to achieve. I expect you don't want the titanium to be passive, rather you want it active as all hell. Maybe if you give it strong curry as an anode in HCl first and then make it the cathode in an electroplating solution without letting it see oxygen. Alternatively, you could just plate it with a full gram of platinum and let it etch as it may. Ive just decided to buy another Pt coin anyway. My electrode is shite but I know how to improve it. I can rebuild it... I can make it better than it was

From my aweful experience with the softening of my electrode + some lit I saw which mentioned this (annealing right?) I believe I can make it thinner and then cold work it to make it strong again. Perhaps heating and slow cooling ine the relatively cold range of 0-200*C could help, we shall see. When I have that I will dissolve my old one (I want some Pt compounds anyway) and maybe I will do a trial electroplate and see how it holds up. I'm going to do some serious reading first. I'm sure that making a cohesive layer can't be simple... it isn't for any other metal...

Antwain, do you rabbit on as much in real life as you do in these forums..

How the hell did lead get into the platinum?

Regards, Xenoid

I have a micrometer that does tenths. 0.0001" = 0.00254 mm = 2.54 um. Microns are actually kind of large, as small measures go.

I prefer to think my complete lack of data implies how foolproof this process is...

I could take measurements, but why bother? Science just slows down chemistry.

Tim

Quote:

Originally posted by Xenoid Antwain, do you rabbit on as much in real life as you do in these forums.. How the hell did lead get into the platinum? Regards, Xenoid

Yes, of course

soldering, followed by heating the Pt wire to red heat 1.5cm away. The solder disappeared into the wire and it went a dull grey, but not like lead on its own. I expect there may be tin there too.

Thanks! Think I'll put it in my sig then

Tim

Hello,

The 'suck it and see' just about sums it up.

I can't remember where I got the 80 micron figure from. I think I sort of plucked it out of mid air (to be honest) as reports of light coating (electroplating anode) were poor. Wearing out, but the users were probably using them in the Chlorate cell that was turning into a Perchlorate cell. Bad thing to do AFAIK. May have seen the 80 Micron in an artical. I am often sorry I do not put in refs. for statements like that.

I used an MMO for a while. It seemed to be wearing a bit. There are many many types of MMO.

Dann2