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Alternative to Electroless Nickel Plating

 April 21, 2010

We currently have a 100 kg pump body machined from a (carbon) steel casting. The media passing through the valve is drilling cuttings from oil exploration. The final stage of manufacture is for the part to have a 100 microns hi phos ENP coating to a tolerance of ±5 microns.

Is there a readily available alternative to ENP that would provide comparable wear resistance characteristics?

Geoff Hume
manufacturer - Stoke on Trent, England

Hi, Geoff. Although it's probably obvious to you, you haven't told us what property or characteristic of electroless nickel you find unsatisfying, so we have no way of proposing something that you might find more satisfying :-)

Chrome plating would provide equal or better abrasion resistance, but it is not as corrosion resistant as electroless nickel. It may be possible to heat treat, or even cryogenically treat the surface for greater abrasion resistance. Salt bath nitriding might be doable and would improve both the corrosion resistance and wear resistance compared to plain steel. PVD processes are probably not applicable because this is an internal surface. ENP is widely used in this sort of application because it is generally very well suited. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 21, 2010

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First of two simultaneous responses -- April 22, 2010

HI Geoff Hume,
For your Application Nylon based Powder coating will help, but the disadvantage is,
1) you will not get the nickel colour
2) Thickness not able to control ± 5 microns
3) You have not mentioned anything about the oil temperature, this type of coating will not withstand approx. more than 110 C

Kannan Boopathi
- Salem, Tamil Nadu, India

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Second of two simultaneous responses -- April 22, 2010

100 Kg pump body is fairly large and presumably has holes in it.
To obtain a tolerance of ±5 mu with any electroplating process would require extensive masking and auxiliary anodes - a highly skilled process for which you pay. Even then with chrome you would almost certainly require a grinding op to achieve the tolerance.
That is why EN is so widely used in the oil industry.
Why do you want to change?

Geoff Smith
Hampshire, England

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If you feel the wear resistance offered by the electroless nickel coatings are not good enough, then try electroless composite coatings incorporated with SiC.

T.S.N. Sankara Narayanan
- Chennai, Tamilnadu, India
(ed.note: The good doctor offers a fascinating blog, "Advancement in Science" )
April 27, 2010

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YOU CAN TRY ELECTROLESS NICKEL BORON OR ELECTROLESS NI WITH NANODIAMONDS
BOTH HAVE VERY HIGH HARDNESS AND WEAR RESISTANCE

Ricardo Burstein
Bnei Berak, Israel
May 1, 2010