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topic 56318

Voltage & timing for nickel strike on stainless belt buckles



A discussion started in 2010 but continuing through 2018

December 11, 2010

Q. Sir,
I am doing trouser buckles of 202 stainless steel.

56318

Nickel Strike solution - Ni chloride (225 gm/litre) and HCl (110 ml/litre)
please tell me the 1. Temperature 2. Voltage 3. Timings 4. Solution

Right now I am doing at 15 volts for half an hour at room temperature.

And what should be the voltage and temperature for bright nickel?

Ashish Jain
industrialist - Delhi, India


December 13, 2010

A. For a Wood's nickel strike, you should use 90 amps per sq ft for no more than 5 minutes. 3 would be OK and possibly even better as it is extremely compressive. I have a hard time believing that 15 volts is required. Add more anode area and space the anodes better, closer to the part would help.

Right now you are wasting a large amount of electricity generating hydrogen, oxygen and chlorine gas.

James Watts
- Navarre, Florida


December 14, 2010

A. Hi, Ashish.

As far as I know, all bright nickel plating baths operate at 140° F. We assume you're rack plating since you've not told us differently. You need 40 amps / sq. ft. for full brightness.

Please try to describe your situation, including what you've tried and what results you got. Without the particulars of your problems, all you can ask for is tabulated operating conditions which are faster, more easily, and more accurately found in a plating book :-)

Good luck, and regards,

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey

December 14, 2010

Q. Thanks a lot for your revert.
Sir,
Lets talk about the strike nickel first only :-
1. I am doing barrel plating (15 kg per lot)
2. I do the plating at room temperature.
3. Plating is done at 15 volts for half an hour.
4. Rectifier shows 100 amperes.

QUESTIONS ARE :-

1. Is my solution of nickel chloride and HCl is ok?
2. What should be the temperature of solution?
3. What should be the voltage and amperes at the time of plating?
4. How much time should be given to plating?

I am getting a problem like when I bend my product after plating - a layer of nickel breaks off the surface.

I am getting very good brightness and shining that I want, but the problem is nickel breakage.

Ashish Jain [returning]
- Delhi, India

December 14, 2010

Q. The actual name of the problem which I face is (NICKEL PEEL OFF)
This is the only problem I'm facing.

Ashish Jain
- Delhi

December 20, 2010

A. Hi, Ashish.

Letter 13745 discusses the composition of Wood's Nickel strike, quoting several formulations, which you can compare with Robert Probert's suggestion in Letter 30307 of 2 pounds per gallon nickel sulphate and one quart per gallon HCl. Your formulation sounds reasonable.

You must estimate the surface area of your plating load so that you can determine the amperage. Letter 38405 discusses the formulation in additional detail, says that ambient is the right temperature, and suggests a current of 30 amps / square foot for 6 minutes--which you can compare to Mr. Watts' suggestion above of 90 amps for 5 minutes and with Jack Dini's "Electrodeposition: The Materials Science of Coatings and Substrates" which mentions 25 ASF [actually written as 268 A/m2] for 5 minutes and says that under certain conditions an anodic pretreatment in 70% by weight H2SO4 at 1070 amps/ square meter may increase adhesion strength. I highly recommend scouring around to find a copy of Dini's book as it has an excellent scientific treatment of the Wood's nickel process.

But peeling of the plating may not be due to improper Wood's Nickel Strike. It can be poor cleaning, but is perhaps most likely to be too highly stressed and non-ductile bright nickel plating. Bending some bright nickel plated Hull Cell panels might be very informative. Best of luck.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey



May 17, 2018 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. What range can the ASF be in the Wood's nickel process. The procedure I am reading says that it shall be done for 60 seconds at 50 ASF prior to plating?

Stephen Page
- Leeds UK


May 2018

A. Hi Stephen. It probably depends on what substrate you are plating on, and what finish will follow the Wood's strike. As a generality 2-5 minutes of striking time sounds typical, so 60 seconds sounds light to me, but if it says 'shall' in a spec, that's what you must do.

Electrodeposition -- The Materials Science of Coatings and Substrates
from Abe Books

or

Jack Dini reported that it doesn't seem to matter whether you strike at 10 ASF or 100 ASF or in between if the next step is gold plating; but if the next step is nickel plating, adhesion got better on AM363 stainless steel with increase in ASF, 44% better at 100 ASF than at 50 ASF, and 9X better than at 15 ASF.

My personal opinion is that if the immersion times and ASF's that someone is using are working and is within the generally accepted range of say 2-5 minutes and 30-100 ASF, there's probably little point in tweaking them or debating them, but that for a new application it's worthwhile reviewing some actual numbers from sources such as Dini's "Electrodeposition" =>

Good luck.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
Striving to live "Aloha"



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