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Nickel Plating Failing 96 Hour Salt Spray Test


Q. I am having a problem with obtaining a nickel plating thickness of 15 microns on a security collar for a lock. (3 cm diameter, 1 cm wide and 0.3 cm thick) I have been told by a plating shop that it is impossible to increase the thickness beyond 8 microns because the base metal is free cast iron. I do not believe this to be true, am I wrong? The part is only lasting 48 hour in a salt spray test and I am aiming for it to last 96 hours. Could the problem be relating to the pre-plating cleaning?



Paul O'Driscoll
- Taipei, Taiwan


A. Please try with following combination

Base material+Copper (4 to 5 microns)+ Ni (15 microns)+chrome flash.

We have carried the salt spray test on the base material steel with combination and our part is passed for 96 hours.

Best of luck.

Bahadur Singh
- Udaipur, India


A. I don't think there's a problem if you can cyanide copper plate first to a thickness of 15 microns before nickel plating. It will also give you better corrosion resistance.

Khozem Vahaanwala
Khozem Vahaanwala
Saify Ind supporting advertiser
Bangalore, Karnataka, India

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"Nickel and Chromium Plating"
by Dennis & Such

from Abe Books
info on Amazon


A. Please try the following :

Critical is the duplex nickel with a potential difference of approx. 100mV.

Jason Wu
- Hong Kong SAR

March 20, 2011 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Nickel chrome plated parts are failing salt spray test.
Sir we are doing nickel chrome plated 12 microns & chrome 3 min, but in salt spray it is staying only 24 hrs but customer needs 75 hrs what should I do?
Please help me.

Ahmed Ahmed
plating shop - Bangalore, Karnataka, India

March 22, 2011

A. Hi, Ahmed.

We've appended your inquiry to a thread that may help answer it (see also letter 53155 "To Pass 24 hours of Neutral Salt Spray Test in Nickel and Chrome Plating"). It strikes me that the fact that you are able to get 24 hours from your current process is good, and serves as evidence that your process is under control -- but that a single layer of nickel 12 microns thick is not up to the task, and you must use a copper undercoat, or duplex nickel, or substantially thicker nickel. Good luck.


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

March 22, 2011

A. 3 min in a chrome tank is barely enough to get color. You will get zero corrosion resistance from that amount. So, You are looking at nickel having to do the job and 12 micron will rarely do the job, even with electroless nickel.

James Watts
- Navarre, Florida

February 15, 2013

Q. Sir I need 8 hrs salt spray for bright nickel job; my job is hollow and is failing after 6 hrs showing red rust,after giving 10-15 microns copper and 18-22 micron nickel.

Sir please give me the opinion for the issue.

Anup Vichare
electroplating - Pune, Maharshtra, India

March 4, 2013

A. Hi,

Read what chemical you have and try to understand why your deposit will corrode. After that I will explain for you why the deposit will corrode.


anders sundman
Anders Sundman
3rd Generation in Plating
Consultant - Arvika, Sweden

April 17, 2013

Q. Hi,

I am using bright nickel plating (Electro plating) mechanical boxes for RF & Microwave components 1 to 18 Ghz frequencies.
These mechanical boxes having small pockets and we found uniformity of plating is not coming in few pockets and, due to this reason, power transistors/modules are getting failed. These are meant for defense and aerospace applications and salt spray test should be withstand minimum 168 hours. Base material for this plating is Aluminum 6061-T6 and copper undercoat 3-5 microns.

So based on above parameters please guide me whether can I use nickel plating for our applications or can I go ahead with trivalent chrome passivation (TCP).

Please let me know the comparison of both (Nickel plating & TCP)

Thank you,

Pavan Kumar
- Hyderabad, Andhra pradesh, India

November 2013

A. Hi Pavan. Yes, Mil-DTL-5541 [link is to free spec at Defense Logistics Agency,] "TCP", properly done on type 6061 aluminum, can pass 168 hour salt spray test. But I have no idea whether doing this process on the boxes will suit the needs of the power transistor modules.

Nickel plating is more reflective than conversion coated aluminum, but it is a barrier layer plating on a more active substrate (the reverse of providing cathodic protection, the aluminum will corrode to protect the nickel plating if the aluminum is exposed by porosity or pinholes). If you choose to nickel plate aluminum, you must choose to plate it really good.


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

July 25, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Sir,
3 microns nickel plated un-annealed CRCA Strip; width =18 mm & thickness= 0.1 mm can withstand how many hours of salt spray test?
Suppose if the same is annealed, how many hours can it withstand?

Chandrasekhar MV

July 26, 2013

A. Hi Chandrasekhar. Unfortunately: zero hours un-annealed, zero hours annealed :-(

Nickel plating is cathodic to steel, which means it is solely a barrier layer which is only capable of protecting steel if it is non-porous and free of pinholes. If there is porosity or pinholes, nickel plating will accelerate the corrosion of the underlying steel, rather than retard it. And there probably will be porosity and pinholes in a 3 micron coating.

Is there a reason this narrow and very thin strip can't be stainless steel instead?


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

July 27, 2013

Q. Sir,
The strip mentioned is used in Ni-Cd Pocket plate Battery electrodes.
I understand that porosity of plating is an important factor in resistance against rust / corrosion.
But then CORUS SPECIAL STEEL (CSS Germany) is making battery grade strip with just 2 microns nickel plating on cold rolled steel adding diffusion annealing to the plating process.

"Hilumin is an electrolytically nickel-plated, diffusion annealed cold-rolled steel strip whose benefits are appreciated by many international manufacturers"

Whereas we are doing 3 microns nickel plating without annealing and we have the problem of rust catching frequently.
How then is it possible?

Chandrasekhar MV

July 29, 2013

A. Thanks for explaining the situation Chandrasekhar! I thought you were talking about annealing the metal before plating; I didn't realize that you were speaking about a diffusion baking process after the plating.

This baking process diffuses the porous cathodic coating of nickel on steel, forming instead a nickel-iron alloy which can presumably be free of pinholes & porosity, while offering an electrochemical potential which is closer to steel and not as galvanically aggressive towards it as pure nickel plating. So again, wheres 3 microns unannealed will not be enough to be non-porous and pinhole-free, 2 microns annealed may form a reliable nickel-iron alloy.

But, sorry, I have no experience with its salt spray resistance. Hopefully another reader is familiar with it.


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

November 11, 2013

Q. The plating shop that I am dealing with said the best they can give me is a 75 hour salt spray test. We have small steel machine parts that are for automotive use in an outdoor environment; I would like to see the parts hit about a five-year longevity. Would 75 hours be enough? The parts would be copper nickel chrome?

Kelly Motherwell
- Ferndale, Washington, United States

A. Hi Kelly. Top quality copper-nickel-chrome plating will easily last 5 years in the worst environments. 15 years or more is possible. But salt spray testing may not be appropriate. Look into CASS or Corrodkote testing as they were designed to be better indicators of the quality of nickel-chrome plating. Good luck.


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

August 6, 2014

Q. Dear all, we are facing the issue in NICKEL plating in salt spray test; we did 12 micron NICKEL plating and it's failed in 20 hours but, customer needs 96 hours. This part's Base Material is EN-9 (Hardened Material).
Please suggest what is the improvement need on this.

S.Jeya Prakash
- Mumbai, India

August 10, 2014

A. Do you do passivation after plating?
If you just want to meet 96H salt spray test, I suggest to add passivation process.

Tony sun
- Xiamen, China

December 16, 2015

Q. Dear Sir ,

I am manufacturing ball pen clips of material spring steel (EN-9 unhardened). After manufacturing we do hardening procedure. But we are finding some difficulty in nickel plating them.

Please suggest how polishing can be performed.

utkarsh gupta
- delhi , india

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