Problems Coating Ni on Ti-6Al-4V
Hello - I found your website on the internet.
We are having trouble with our current vendor who is plating nickel onto our hydraulic actuator cylinder bores.
The coatings have poor adhesion, blistering, pits in substrate, excessive mud-cracking...etc.
Can you please send or fax me any information you have on plating titanium, or call me to discuss this process at your earliest convenience.
Best Regards,Terence Savas
I am no electro plater but I have some knowledge of titanium.I have a solution to your problem of Nickel plating on Ti-6Al4V.
You are unable to achieve Ni plating on Ti possibly due to process limitation in the presence of a tenacious oxide film which inhibits plating adherence. Here is a step by step procedure which will solve your problem
1)Scour with pumice powder and alkaline solution containing 50 g/l of Sodium hydroxide and 50 g/l sodium carbonate
2) rinse with water
3) Etch in hydrochloric acid solution containing .05 g/l choloroplatinic acid at 30 °C.Immersion time required varies with the alloy.Eg:2 Hours for IMI 314 and 10 minutes for IMI 680
4)Transfer the etched titanium to a solution containing 50 g/l Rochelle salt at room temperature. Gentle agitation is required.
5)Transfer rapidly to a copper tartrate plating solution containing 50 g/l copper sulphate ,160 g/l Rochelle salt ,50 g/l Sodium Hydroxide.Load live and plate for 5 minutes at 0.4 A-(dm square)
6)Rinse in water containing 1 v/o sulphuric acid
7)plate with nickel
8)Rinse and dry
9)Heat treat if necessary
Refer ASTM B481 [link by ed. to spec at TechStreet]-68 "Recommended practice for preparation of titanium and titanium alloys for electro plating". I hope this will solve your problem.
With warm regardsNG Krishnan
hindustan aeronautics limited - bangalore .karnataka .india
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