Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ

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Electroless nickel-boron plating

Tip: Readers want to learn from your situation,
often just skipping abstract questions.

Q. Why do we need to have Nickel phosphorus coating on Aluminum alloy before we apply Nickel Boron onto it?

Patil Sandip P
Hobbyist - Pune, India
August 9, 2022

A. Hi Patil. Who said you need to do that? Maybe you do, maybe you don't.

Or did you learn from experience that you need to do that? If so, what happened without nickel phosphorous?

Maybe your masking material won't/didn't hold up to the high pH if you're talking about nickel borohydride baths. Or maybe your zincate or zincate replacement chemical dissolved rather than holding up to nickel borohydride. Then again, maybe it will.

Abstract questions are at best impractical to answer, and often impossible. Please provide details about your situation. Thanks.

Luck & Regards,

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

⇩ Related postings, oldest first ⇩

RFQ: Where can I get Ni-Boron Electroless Coating Supplier?

Can I get a data sheet?

Thanks.

ILAN ZOHAR
1997

Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)

Q. Dear Sirs, I wish to know about nickel boron electroless plating. My nearby institution tells that they can provide me with electroless plating of nickel and they are not sure about nickel-boron plating. My end use requires hardness of 730 Hv whereas nickel can go only up to 500 Hv.

If I take the technology of electroless nickel plating, can it be used for nickel-boron plating also with any modifications. Please help regards Sukumar

r.sukumar
- coimbatore, Tamilnadu, India
2003

A. Nickel-boron plating solutions are available from several plating chemical suppliers, Macdermid, Uyemura, Shipley and others. The as plated hardness is from 730-750 knoop 100 gr load.

Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [on Amazon or AbeBooks affil links]
and "Plating ABS Plastics" [on Amazon or eBay or AbeBooks affil links])

A. Yes, you can plate nickel-boron with any type of electroless plant under condition of solution suppliers, e.g., Mr. Baudrand said.

Vahid Hosseyni
- Tehran, Iran

Thin Electroless Nickel low stress films

Q. I am plating with Boron Electroless nickel on semiconductor wafers. The problem is two fold:

1) To much stress, Question How do I get the lowest possible stress, an additive to the bath?

2) Plating too fast, Question How to lower the plating rate to 500 Ang/min. (I only want to plate 1500 Ang ± 150 Ang, this means that I need a 3 to 5 min process for controllability.)? I suspect that the answer to #1 will also answer #2.

Thank You for your help.

Hector E. Celis
Semiconductor Engineer. Thin films - Lee's Summit, Missouri, USA
2003

A. The internal stress of Ni-B deposits is naturally quite high, Mallory ("Electroless Plating" by Mallory & Hajdu [on eBay , Amazon, or AbeBooks affil links] ) reported stress values of 69K psi for coatings containing 0.23%B and 44K psi for 1.2%B. Slowing the bath down (by lowering the temperature and pH to manufacturer's minimums) will allow better control of thickness and will also directionally reduce stress. However, it will probably also increase the coating's boron content and reduce solderability.

I have not personally tried this, but several years ago I was told that the addition of several ppm of thiourea ⇦this on eBay or Amazon [affil links] would reduce stress and hardness of DMAB reduced coatings.

Ron Duncan [deceased]
- LaVergne, Tennessee
It is our sad duty to note Ron's passing on Dec. 15, 2006. A brief obituary opens Episode 13 of our Podcast.

A. I agree with Ron Duncan. However, be careful adding thiourea ⇦this on eBay or Amazon [affil links] because at low bath loading thiourea will poison the reaction and stop plating. If you add it use 1 ppm to start, maximize the bath loading (sq ft/gallons of solution 0,25 sq. ft./gal is minimum) Lower the pH to the low limit recommended in the suppliers data sheet. The stress will be slightly less and the plating rate will be slower. (in addition to lowering the temperature)

A. Hi, all.

Two good books covering the topic are:
Chemical (Electroless) Nickel Plating by G.G. Gawrilov and
"Electroless Plating: Fundamentals & Applications" by Mallory & Hajdu [on eBay , Amazon, or AbeBooks affil links]

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Chemical composition of B-Ni electroless Plating Bath

Q. Anybody can help me? I have a problem when starting to do electroless Ni Plating with Boron Nickel Autocatalytic Process. I want to know How many grams of Sodium Borohydride (NaBH4), NiCl2, EDA and other chemicals are required for 1 liter solution to get an optimal process. My specimen is a toroidal aluminium Di=100mm Do=150mm.

Thanks a lot for your answer.

Arif Indra Sultoni
engineer - Surabaya, East Java, Indonesia
2004

A. Here in the USA plating shops buy the electroless nickel chemistry from suppliers who specialize in it rather than having hundreds of individual plating shop repeating the same development work of trying to design a good process themselves. So I'd suggest you consider goin to a supplier and buying a nickel boron proprietary process.

You're welcome to do it your way, of course, but our problem becomes that if someone responds -- considering the anonymity of the internet -- we have no way of knowing that the responder came upon the knowledge legitimately, or they are who they say they are, and are not blowing a trade secret.

So we'd prefer for people to offer a reference (book title or journal article) where you may look up this information.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Borohydride reduced nickel boron coatings were developed in the 1960's by BASF in Germany and by DuPont in the USA. The plating solutions were historically made by the platers locally. There were no proprietary suppliers of BH4 reduced solutions until recently. Today, there is one supplier in Florida who will sell solutions. (DMAB reduced nickel boron is different and is supplied as proprietary solutions by several companies.)

The formula for the operating bath has been published many times by BASF and others. It is listed in the AESF's Electroless Plating text by Mallory and Hajdu. The bath is only nickel chloride, complexed with ethylene diamine, neutralized with caustic, reduced with sodium borohydride, and stabilized with thallium sulphate.

Ron Duncan [deceased]
- LaVergne, Tennessee
It is our sad duty to note Ron's passing on Dec. 15, 2006. A brief obituary opens Episode 13 of our Podcast.

Thanks Ron. I yield to your far deeper knowledge of the subject and cheerfully stand corrected.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004

A. Life is not so easy. It is true that this particular formulation you can find in books but yet, Ted is right. Someone has to give you the process because maintaining such a bath is not simple.

Sara Michaeli
Tel-Aviv-Yafo, Israel

Boron content in electroless Nickel-Boron bath chemistry

Q. I've been looking for a particular EN bath composition that gives a non-magnetic Ni-B deposit, by solely tinkering with the Boron (DMAB) content. At what percentages of Boron content in bath and in deposit give me the non-magnetic property I am looking for? What particular bath make-up (proprietary brands?) should I use?

Bob Rudes
- Santa Clara, California, USA
2005

A. A Ni-B deposit will should become non-magnetic at 6 or 7 percent boron content. There are no commercial Ni-B plating solutions that will deposit this much boron. DMAB solutions are limited to about 2 or 3 percent boron. Borohydride reduced baths will deposit about 5 percent boron.

Ron Duncan [deceased]
- LaVergne, Tennessee
It is our sad duty to note Ron's passing on Dec. 15, 2006. A brief obituary opens Episode 13 of our Podcast.

A. I agree with Ron Duncan that it is very difficult to prepare Ni-B deposits with 6-7 wt% boron using DMAB bath. We have prepared EL Ni-B coatings with about 6-7 wt% boron using an alkaline borohydride reduced electroless bath. In as-deposited condition it is non-magnetic.

you can refer the details of our work in

Formation and characterization of borohydride reduced
electroless nickel deposits
Journal of Alloys and Compounds 365 (2004) 197-205
Published by Elsevier Science Publishers.

T.S.N. Sankara Narayanan
- Chennai, Tamilnadu, India
(ed.note: The good doctor offers a fascinating blog, "Advancement in Science" )

Q. Thanks Ron.

To Dr. Narayanan: If alkaline borohydride-reduced EL Ni-B gives me a non-magnetic deposit, I would just like to ask for, say, a simple 5 gal bath make-up recommendation to play around with. I have neither the time nor the resources to look for and wade through what could be a very comprehensive published paper of yours on the subject. I'm conducting a very simple experiment under time constraints for "up-and-down" results....

Thanks again to Ron Duncan and Dr. Narayanan.

Bob Rudes
- Santa Clara, California, USA
2005

A. I achieved 10% by Wt. boron using a DMAB plating solution by adding powdered boron to the bath that co-deposited. The deposit was heat-treated to alloy the boron and nickel. Note: About 10% is the eutectic alloy (lowest melting point) and non-magnetic.

Multiple threads merged: please forgive chronology errors :-)

Electroless Nickel Boron coating

Q. Hello! I am a student doing a university project on "Electroless Nickel Boron coating" on mild steel substrate.
My electroless bath is alkaline and I am using the following chemicals for the bath :-

Nickel Chloride - Nickel source
Sodium Borohydride - reducing agent
Sodium potassium tartrate ⇦this on eBay or Amazon [affil links] - complexing agent
Sodium hydroxide
ammonia ⇦this on eBay or Amazon [affil links] solution - To get the pH > 12

The problem faced by me is regarding stabilisation of the bath. Above 65 °C the bath turns blackish and also I am unable to deposit for more than 20 min.

So I want advice regarding a suitable stabilizer which can be used and would go perfectly with the rest of the bath chemicals. Also any other tips regarding the stabilisation is also welcome. Thanks in advance.

Suman Das
student - Kolkata, West Bengal, India
August 14, 2008

A. See if a library can get a copy of the electroless plating book (Electroless Plating - Fundamentals & Applications) by Mallory and Hajdu. You can get the full name and other information at the books portion of the home page of this site. In the USA, we could get a copy on an inter library loan.
Also, "Modern Electroplating" [on AbeBooks, eBay, or Amazon affil links] has a couple of pages on it. This book should be easier to get, but nowhere near as complete.

James Watts
- Navarre, Florida

A. Dear Suman Das,

You can add mercapto benzothiazole as a stabilizer for the bath.

if you want higher plating rate and better bath stability then you can add thallium acetate as the stabilizer.

Please remember that thallium salts are highly toxic. Please read the Material Safety Data Sheet before using such chemicals.

T.S.N. Sankara Narayanan
- Chennai, Tamilnadu, India
(ed.note: The good doctor offers a fascinating blog, "Advancement in Science" )

Q. Thank you Mr. Narayanan and Mr. Watts for your response.

May I know if I could use Lead nitrate or lead acetate as the stabilizers instead of the thallium nitrate with more or less same effectiveness ?

Suman Das [returning]
- Kolkata, Wets Begal, India
August 19, 2008

A. You can use lead nitrate as the stabilizer. But the rate of deposition will be of the order of 6-8 microns per hour. If that will suit your application, then you can use lead nitrate instead of thallium salt as a stabilizer.

Please remember that lead is also toxic.

T.S.N. Sankara Narayanan
- Chennai, Tamilnadu, India
(ed.note: The good doctor offers a fascinating blog, "Advancement in Science" )

Q. Dear sir

1. I am working in aeronautics and located in Karnataka state. 2. Presently we are using 10-13 % phosphorus content Electroless nickel plating and the process chemistry is from a major USA supplier.

3. Our material Tempering temperature is designed up to 150 °C only. It cannot be increased as per the chemistry to control distortion of splines of the component.

4. We require wear resistant property, hardness of 700 to 800 vickers only

5. After plating in the present chemistry bath we are getting hardness of 450-500 vickers and what so ever increasing baking temp or time we are getting limited hardness only up to 60 vickers as tempering temp is restricted to 150 deg and as per the chemistry of high phosphorus EN chemistry if tempering temp is up to 450 deg then baking at 400 deg for some time (established by trials) micro hardness can be easily established for the part.

Our design criteria:
-- 16 NCD13 is fixed and No alternative material can be now changed
-- Tempering temp is fixed up to 150 deg only to prevent distortion of splines
-- We require micro hardness of 700 to 800 vickers and I have heard that there is either high temp or room temp Electroless NICKEL BORON where we get directly as PLATED HARDNESS IN THE BATH WITHOUT POST HEAT TREATMENT OR BAKING

BUT I still have doubt that even in case of low phosphorus content also baking temperature is restricted only to tempering temperature of base material and hence adopting this chemistry is affecting my decision.

I am facing a dilemma.
Can you suggest suitable EN - Nickel Boron Room Temp or low temp process which can be established with minimum time and capital investment

Send me the technical details like:
Technical details of Electroless NICKEL BORON plating (containing 1-3% Boron) chemistry to meet my process requirements
TDS, MSDS and Minimum order quantity details
Budgetary quotation for related chemicals involved in the entire process stages
Send me the contact distributor or dealer in India or ASIA PACIFIC region for easy accessibility

Megha Shyam
process designer in aerospace industry - Karnataka, India
June 4, 2009

Pitting problem in electroless nickel-boron plating?

Q. I am working on plating Electroless Ni-B on sphero cast iron products. But after every coating try, I have the same problem. On the surface of the final coating I have pits. And I can see the formation of this pits during the deposition process.. Because during the deposition, some bubbles settle on some areas of the surface.. Therefore coating can not take place on that bubbles and in the end I have pits on that regions. I couldn't have any smooth and clean surface so far.

I've tried different pre-treatment methods, including pickling... without pickling.. nothing changed. I couldn't understand why that bubbles occur.. I tried agitation also but it was not a solution neither.

How can I stop that pits formation...

Should I try a nickel or copper strike? If I should, which one would be proper?

Thanks already,

Sincerely yours...

Sinem Eraslan
- Istanbul, Turkey
October 21, 2009

A. Your vendor of chemicals must be able to solve the problem. If you have a home brew chemistry you are in trouble. You may want to try adding different surfactants in different concentrations to small amounts of solution in a beaker [beakers on eBay or Amazon [affil links] and put them to work. Eventually, you may find one that works without appreciable long term effect on the reactions or deposit properties.

Guillermo Marrufo
Monterrey, NL, Mexico

A. Hi Sinem,

Gas bubbles generated during and EN process is very common. It is necessary to have agitation to improve the process, also the type of agitation is very important (rocking, shocking, vibrating and etc). From you info, I think you have not try vibration or shocking.

Changing chemical formulation is also another method but it will be very difficult to control, especially if you make your own EN.

Try adding a vibrator onto the Jig, it should help improve your problem.

Good Luck.

Robin Chua
- Singapore

A. Surfactant, agitation and filtration should solve the problem.

Sara Michaeli
Tel-Aviv-Yafo, Israel

Proper thickness for electroless nickel boron plating

Q. Hi, please give me indication of normal plating thickness (or limitation of max. thickness due to high stress) of electroless nickel boron. my substrate is high stress fine stainless wire with dia. 0.5 mm. Thanks.

Fengmin Liu
Plating shop - Singapore
July 14, 2010

A. Internal stress is an important aspect of plated films.

You have not mentioned your application area and thickness requirement to satisfy the functional properties.

Pre-treatment of the stainless steel wire using glass bead blasting/peening will induce compressive residual stress. This might help reduce the tensile residual stress in the electroless Ni-B coating.

T.S.N. Sankara Narayanan
- Chennai, Tamilnadu, India
(ed.note: The good doctor offers a fascinating blog, "Advancement in Science" )

Possible to achieve mirror finish on Nickel Boron (HRC 67) in a vibratory tumbler?

Q. Hi,
I am trying to achieve a "mirror" finish on some gun parts I had coated in Nickel Boron. The Nickel Boron has an HRC of 67 and has not had any finish after coated leaving it shiny but not reflective. I do not need to active a perfect mirror finish, just a consistent finish I can see myself in. The parts include several small parts like the hammer, trigger, small pins as well as the bolt (7" x 3/4" ID cylinder) of the rifle. Most of the small parts all have 90° angles . I would only have a 18 lb vibratory tumbler at my disposal. With all the various media and chemicals I have no idea what might be effective. Any advice would be high appreciated.
Thank you.

Richard Baker
Hobbyist - Nashville, Tennessee, United States
April 20, 2015

A. Richard,
A better way would have been to try tumbling the parts to achieve the desired finish prior to plating. ENB is usually a fairly thin coating and I do not think it would be a good idea to tumble after plating in order to achieve a mirror finish. Perhaps remove the ENB, tumble or polish and then re-plate.

Blake Kneedler
Feather Hollow Eng. - Stockton, California

Friction coefficient for Electroless Nickel-Boron Plating

Q. The friction coefficients for Electroless nickel-boron quoted by different suppliers are all over the map. I realize that the surface finish and substrate plays a role, but I still expect a tighter distribution of CoF. Can anyone shed some light on this?

My application involves a sliding motion of Stainless (actually 1095 spring steel) on tempered aluminum substrate (6061 and 7075). Finally, because the Aluminum is tempered, what is the max process temperature that will achieve sufficient adhesion without annealing the aluminum?

S Saba
- San Jose, California
June 17, 2015

A. Friction coef. for Boron plus thalium EN is 0.44.
I have no info as for Nickel Boron with no thalium.

Sara Michaeli
Tel-Aviv-Yafo, Israel

RFQ: Can you suggest an EN Boron company? From what I can google, there is so few companies that will electroless nickel boron plate.

Richard Johnson
Engineer - Calgary, Alberta, Canada
August 13, 2015

A. Hi Richard. We don't post sourcing recommendations in this forum (why?), but look near the bottom of the page, and you will see that we are running an ad for a well-known EN-Boron plating shop. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Boron Electroless Nickel Plating Blistering Issue

Q. My name is Ben Hartford, I am a plating Engineer in North America. I have and issue with blisters after sintering on MoMn metallized ceramics that have been plated in our Boron electroless solution. I am using MacDermid's Niklad 752 solution. We are using it at a different pH then recommended (5.0-5.5) because if we use it within the spec. range we get even more blisters. Since MoMn is not auto-catalytic, we use an electrical jump start to initiate the plating reaction. I'm a mechanical engineer by degree so a lot of what I do to solve problems like this is a lot of research, trail and error. One thing that I have tried is applying a Wood's Ni strike before electroless plating (makes the process auto-catalytic). This works on the small scale plating 1 by 1 with tweezers but, I have trouble when I try to scale up in a barrel ... I get no nickel after several runs at 30-50 ASF. I have a few other ideas such as slowing the ramp rate on our sintering profile and possibly trying a palladium chloride catalyst but other than that I am out of ideas. Any idea what could be causing the blisters and how to eliminate them?

Benjamin Hartford
Plating Engineer - Laurens, South Carolina United States
June 26, 2019

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