# Titanium platinum plating question



## Atto (Nov 19, 2014)

I'm working with rhodium plating baths and our supplier is having great difficulty importing those anodes. Since we have platinum baths (P salt) we want to know how to plate platinum in titanium (grade 2).

Does the commercial platinized titanium anode is made by plating platinum? Or other method?

I already tried some ways; 
*Degreasing, activating in HF and HNO3 then plating in the activated surface. 
*Degreasing, activating in HF and HNO3, anodizing (oxalic acid solution) and then plating in the anodized surface.

I tried 10V and 32V, but none of them was successful. In all tries the platinum layer came off just by rubbing my finger.

I know the dangers of HF, I'm taking all the necessary precautions.

Thank you all =)


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## Lou (Nov 19, 2014)

Anneal coating under hydrogen, dull red heat, then use.

shoot me a message if you're interested in any P salt.


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## Atto (Nov 20, 2014)

Hello Lou!

Thank you for the answer.

I'm asking myself why the method I described didn't work, I saw in many articles and old patents, people doing just what I did and reporting they were successful at creating an Pt/Ti anode.

I also saw on some patents that you could anneal to create a better anode for chlorine production, because the annealing creates a diffusion layer of Pt on Ti, but wouldn't be necessary for a anode used in less drastic conditions.

For the annealing process, could you describe the equipment normally used?

For how long should I anneal? Dull red heat is +- 700 °C (1300 °F)?

The solution I'm using for plating is made from platinum diamino dinitrite and sulfamic acid, it doesn't have any brightener, hardener, etc...

Articles:
http://www.maneyonline.com/doi/abs/10.1179/174329407X260582
http://link.springer.com/article/10.1361/105994903770343402

*If someone want the articles, I can send them, just PM me.


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## Lou (Nov 21, 2014)

I am happy to quote on Pt/Pd plating salts. We will make them on request for customers.

I always suggest annealing. Usually done in 5% H2/balance argon so that the Pt diffuses into the Ti.

If you're sonicating w/ detergent it to degrease, then HF or hot oxalic acid (even ammonium bifluoride with a bit of sulfuric works, 10g/L)....it should plate quite nicely. 

Just anneal in a box oven.


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## Atto (Nov 27, 2014)

Lou,

We are trying but not succeeding in plating the titanium, the plating metal doesn't adhere on the titanium.

We tried platinum, then we changed the plating bath to acid copper, because this is the bath that we have more experience.

Here are some of our several tries:



1) Degrease cathodically in a basic electrolytic bath 7,5V amb temp

Deionized water rinse

Acid pickle in a solution of nitric acid (400 g/L) and hydrofluoric acid (50g/L) amb temp

Deionized water rinse

Plating Bath - Platinum or Copper



2) Degrease cathodically in a basic electrolytic bath 7,5V amb temp

Deionized water rinse

Acid pickle in a solution of nitric acid (400 g/L) and hydrofluoric acid (50g/L) amb temp

Deionized water rinse

Boil in oxalic acid (100 g/L)

Deionized water rinse

Plating Bath - Platinum or Copper



3) Degrease cathodically in a basic electrolytic bath 7,5V amb temp

Deionized water rinse

Acid pickle in a solution of nitric acid (400 g/L) and hydrofluoric acid (50g/L) amb temp

Deionized water rinse

Boil in oxalic acid (100 g/L)

Deionized water rinse

Anodizing in amb temp oxalic acid (80 g/L) – *10 V* and another try *32 V*. Both of them at 20 mA/cm² - spaced 2 cm

Plating Bath - Platinum or Copper



4) Degrease cathodicaly in a basic electrolytic bath 7,5V amb temp

Deionized water rinse

Acid pickle in a solution of nitric acid (400 g/L) and hydrofluoric acid (50g/L) amb temp

Deionized water rinse

Boil in oxalic acid (100 g/L)

Deionized water rinse

Anodizing in amb temp oxalic acid (80 g/L) – *10 V* and another try *32 V*. Amps not limited – spaced 2 cm

Plating Bath - Platinum or Copper



5) Degrease cathodically in a basic electrolytic bath 7,5V amb temp

Deionized water rinse

Acid pickle in a solution of nitric acid (400 g/L) and hydrofluoric acid (50g/L) amb temp

Deionized water rinse

Etch in solution of sodium dichromate at 225-263 g/L and 4-5% v/v hydrofluoric acid for 15 min

Deionized water rinse

Plating Bath - Platinum or Copper



6) Degrease with ultrasonic cleaner and detergent

Deionized water rinse

Acid pickle in a solution of nitric acid (400 g/L) and hydrofluoric acid (50g/L) amb temp

Deionized water rinse

Plating Bath - Platinum or Copper



*acid copper bath = 1,2 V (~ 0,6 A and 0,1 A/cm²), anode with much greater surface area than titanium piece



Here are some photos of the #6 try, as you can see the titanium hook plates nicely, but it flakes off once twisted and the titanium piece doesn't plate at all. Before try number 6 I heated the piece with a torch until red hot, to eliminate possible titanium hydrides...

Titanium hook that hold the piece to be plated:




Titanium piece immediately after the copper plating:




Copper plating can be removed with a gentle touch:





Do you know how I can solve this problem!!?? Thank you for you help!


On the quotation of the Pt salts, do you have a minimum quantity? How much is for 10 g of Pt in the form of Pt(NH3)2(NO2)2? Thanks!


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## Lou (Dec 5, 2014)

See PM and also attached may be helpful review.


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