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Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Electroless nickel plating on titanium alloy
Q. I have a requirement to build up an internal bore of a part made from 6AL 4V. I need to add approximately .0002-.0005 per side in a .250 diameter hole. The bore needs to be hard for good wear resistance. I was told that hard chrome is not advisable, but to consider electroless nickel. Is this possible?
Regards,
- Newbury, Massachusetts
2005
A. You may want to consider brush plated hard nickel. It has outstanding adhesion to hard-to-plate materials such as titanium, is very hard (around 50 Rc) and is indicated when only a certain part or small area needs plating.
Guillermo MarrufoMonterrey, NL, Mexico
2005
Multiple threads merged: please forgive chronology errors :-)
January 20, 2008
Q. Hi, I would appreciate it if someone directs me to a procedure, location, person or company, so I can find how to electroless nickel coat a 1 inch width X 4inch length piece of Ti6Al4V titanium alloy (thickness of 2 mm).
I have tried this method and failed to achieve proper adhesion..
1. Grit blasting - aluminum oxide
2. Immerse in a bath of NaOH solution
3. Rinse with distilled water at
4. Immerse in a bath of HCl solution
5. Rinse with distilled water
6. Immerse in a mixture of acetic acid
⇦this on
eBay
or
Amazon [affil links] and fluoboric acid
7. Rinse with distilled water
8. Immerse in a mixture containing dimethylformamide, 150 water, HF at room temperature. Evolution of gases is expected. Immersion until gaseous evolution ceases.
9. Woods strike at room temperature
10. Electroless Nickel plating step
Thanks.
Ricky
student - hamilton, Ontario, Canada
January 31, 2008
A. Plating on titanium is not easy and adhesion is always a challenge. For electrolytic plating one author recommends:
1- Pickle HF 33%, H2NO3 67% room temp until red fumes.
2- Rinse
3- Etch Na dichromate 250 g/L, HF 180g/L, 90-95 °C, 20 min.
4- Nickel plate (also Cr6+ or Acid Cu)
5- Bake in inert gas at 350-650 °C.
Alternatively, for many years, brush (selective) plating has been regarded as an excellent method for plating small areas and simple geometries with outstanding adhesion.
I wouldn't recommend other methods like blasting and immediately follow with plating.
Good luck,
Monterrey, NL, Mexico
February 20, 2008
A. Hi
Try this:
CLEAN
PICKLE
ACTIVATE
BRASS PLATE
COPPER PLATE
ELECTROLESS NICKEL
LONG WAY ROUND - BUT WE PLATE THOUSANDS OF COMPONENTS THIS WAY AND IT WORKS BRILLIANTLY.
GOOD LUCK
WARREN
- South Africa
Thanks Warren. What does "Activate" entail in this process -- is it an acid, a proprietary solution, a Wood's nickel strike, etc.?
A. Here are some additional thoughts --
Anders Sundman offers a good bibliography on the subject in letter 13456, "Blistering problems in Nickel Plating on Titanium" as well as in letter 278, "Plating Nickel onto Titanium".
But best adhesion seems to involve a high temperature process where nickel plating is diffused into the titanium, and excluding oxygen helps too. Back to letter 13456 again, Anders notes terrific adhesion of 300MPa by selective brush plating in an argon tent, then baking at 450 °C. And, in addition to Guillermo Marrufo's helpful insights above, in letter 40558, "Poor adhesion of plating onto titanium", he offers the anecdote of creating an outstanding bond when a titanium heater in an electroless nickel tank ran dry to 500 °C for a short time.
If readers have the time, they will find dozens of suggestions and reports by searching this website.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 28, 2013
Q. Dear sir,
We have been interested in plating electroless Nickel onto Titanium alloy.
We have tried many different pretreatment methods such as HF& HNO3, ammonium bifluoride and H2SO4, HCl & TiCl4, Dimethyl chloride and HCl and strike with Wurtz Nickel followed by EN.
But still the adhesion of the coating to the substrate is questionable.
It forms blisters and peels off with respect to increasing coating duration.
Please advise us a suitable solution to solve this problem.
Thank you,
With best regards,
M.GANESH
National Aerospace Laboratories - Bangalore, Karnataka, India
A. Hi Ganesh. You refer to Wurtz Nickel (Adolph Wurtz is credited by some as the inventor of electroless nickel), but from context I think you meant Wood's Nickel (Donald Wood invented the Wood's nickel strike).
We appended your inquiry to a previous thread which offers some good hints, but I think the main thrust is that getting really good adhesion onto titanium cannot be done by plating EN directly onto the titanium, but will involve extensive activation and the deposition of a layer of a different layer of plating first. I think Anders suggestion of brush plating of nickel in an inert atmosphere followed by diffusion baking is the ultimate answer for near-perfect adhesion.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 2013
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