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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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Watts vs Woods Nickel Strike
2000
Q. My name is John Sartor and I am a process manager for a medium to large plating facility in northwest Ohio. I started out with this company as a racker 7 years ago and worked my way up. The things I know about plating are based only on my experiences in this company. That's just to let you know that I am not a rocket scientist in this industry and my technical expertise is limited to my experiences. My company is contemplating a process change and I would like some comments as to the pros and cons of this change. We do most of our plating for the automotive industry (fuel rails, brake lines, steering components, etc.) The processes our particular plant use are the alkaline zinc and alkaline zinc nickel alloy. Some parts we plate (fuel senders for one) are a combination of low carbon steel and stainless steel tubing. Consequently we have to use a nickel strike before plating for adhesion purposes. We have always used the Wood's nickel strike for this purpose. We have had success using this strike but occasionally experience problems. The ability to manipulate this bath as we experience these problems is limited. One of our other plants which plates chrome and electroless nickel use the Watts' nickel strike. The ability to control it with buffers I am told makes it easier to use. I am told it has better throwing also. We have contemplated going to a Watts' strike some time ago but was dissuaded when my plant chemist was under the impression that the drag-ins of sulphates to our plater would be poisonous. One day my plant manager was talking to our chemical salesman from Macdermid and asked him about the sulphates being poisonous to the platers. He called his company's chemists and asked them about that and they said it was nonsense and as a matter of fact that one of the additives we put in our bath contains sulphates. To make a long story short I would like some comments about the pros and cons of switching to a Watts' strike. The strike we are contemplating is a modified (I'm told) Watt's strike consisting of
- NiSO4 @ 15oz/gal
- NiCl2 @ 15 oz/gal
- H2S04 @ 5%
- HBO3 @ 1 oz/gal
- Temp: 105 degrees
Sincerely,
John Sartor- Toledo, Ohio
A. On stainless steel, Wood's nickel is the strike of choice for the best adhesion, for most platers. It is not idiot-proof and requires some carbon filtration and some dummy to keep it optimal. Because of the very low pH and very high chloride content is will attack the steel more than the modified Watts strike will. This is not a problem with most, repeat, most parts.
Consider going to a Sulfamate strike. It is very close to your Watts strike but uses sulfamate nickel vs. nickel sulphate. The pH must be controlled! Since it is several orders of magnitude less acid than the Wood's strike, it lays down the metal considerably faster. You will have to pay more attention to the etch cycle than you do with the Wood's strike because it is nowhere near as self activating on the SS. It is also a room temp or very slightly elevated bath temp.
The Wood's strike is a more hazardous bath than the other two from the standpoint of acid.
James Watts- Navarre, Florida
2000
Q. What would be a typical Wood's nickel bath composition?
Robert Sachs- Morrisburg, Ontario, Canada
2002
A. Hi, Robert. You'll find the formulation for Wood's Nickel and the operating conditions in the Preparation article by Steve Rudy in the Metal Finishing Guidebook, but it's basically 2 pounds per gallon nickel chloride and 1 quart per gallon Hydrochloric Acid. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2002
Q. Wood's Strike is highly acidic and Iron build up is faster. We have checked that iron also get co-deposited in thin nickel strike deposit. Can anybody suggest the method for removal of Iron impurities. What should be the maximum permissible limit for such impurities.
Bath being highly acidic, it appears impractical to eliminate Iron by raising pH after oxidation.
- Mumbai, India
2007
Q. How does Wood's nickel and Watts' nickel react on SS parts?
Archana elangovan- India
April 12, 2012
A. Hi, Archana.
Please invest at least a few sentences on your question because I don't know what you are asking. But as James noted, Wood's nickel strike is the standard (and usually the best) strike for stainless steel. John seemed to be looking for something that wouldn't attack steel as rapidly.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 14, 2012
Q. May I ask with the formula of Woods Nickel Strike,
2 pounds per gallon of nickel chloride & 1 pound per gallon of hydrochloric acid; my question: is that a gallon of distilled water for the formula please?
- COOROY QLD AUSTRALIA
March 16, 2015
A. Yes, cousin Geoff, but always proceed from authoritative sources like the one referenced, not directly from the internet where people may not even write a complete sentence in reply -- let alone offer a proper tutorial introduction to the subject, complete with the necessary safety instructions :-)
You certainly don't want to build a chlorine gas generation facility while trying to set up a Wood's Nickel Strike tank :-)
Luck and Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 2015
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