Letter 17007

Pretreatment and plating Ti6AL4V  

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Hi,
I'd like to have some help to discuss my suggestion for plating nickel on titanium Ti6Al4V.

1. Blasting with dry 120 grit aluminium oxide or with wet 500 grit aluminium sludge.
2. Rinse.
3. Electro cleaning for 1 minutes.
4. Rinse in citric water ( It's to complex binder the TiO2.)
5. Etch in HNO3-HF for 1 minute.( It's for the Alpha phase)
6. Rinse in citric water.
7. Etch in HCl-NaF-NaCl for 1 minute. ( It's for the Beta phase and also to activate the Vanadium which will be passivated in HNO3-HF.
8. Rinse in citric water.
9. Etch in Na2Cr2O7-HF for 5 minutes.( It's for the Alpha phase and also to clean the area from aluminium oxide from step No 7
10. Rinse in citric water.
11. Activation in Citric-HF for 1 minutes. The area should be light grey like a stainless steel surface at this step.
12. Rinse in citric water.
13. Nickel strike with a high CD for a few sec, and after that normal CD. ( It's to get a Titanium hydride at the surface.
14. Nickel plate.
15. Bake at 480 deg. Celcius.

All these pretreatment steps and plating are done in an argon air atmosphere. This pretreatment should give an adhesion about 150-300 Mpa. I hope people who enjoy this site here at finishing.com will discuss this operation so it could be better.

Best Regards,

Anders Sundman     surface finishing engineer Sweden

Have you attempted this yourself with sucess? I like the citric rinses makes a lot of sense. j

Jon Quirt
- Fridley, MN

Jon,
Yes this pretreatment step woork for me. The adhession I have got is from 58-80 Mpa. Next step for me is to se if the adhession will be better if the bake is 4 hour instead for 2 hour. The citric acid is to complex binding the titanium oxide.

Anders S

Anders Sundman     surface finishing engineer Sweden

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