finishing.com -- The Home Page of the Finishing Industry
no_pop_no_spam
HomeFAQsBooksHelpWantedsForum  letter 27089

Serious Education ... plus the most fun you can have in metal finishing.

Electroplating Hard Material -- Tungsten?


(2004)

Q. I am a researcher in Microsystems and am looking for a material which is hard and conductive which can be electroplated. Particularly I would be interested in tungsten if it is possible. Can anyone offer any input on this?

Also if anyone knows how to increase the stress in nickel electroplating the info would be gratefully received.

Michael Cooke
R&D - Durham, UK


(2003)

A. Hi Michael. Tungsten cannot be electroplated from a conventional aqueous bath, but that is not the only coating technology available. Chromium is probably one of the hardest electroplateable materials but maybe you already considered that one. Composite plating with diamond or other particles may be useful to you. Rhodium is hard, but extraordinarily expensive and perhaps not thick enough.

Chlorides should drive the stress in nickel electroplating through the roof.

Please tell us what you are trying to do. Thanks!

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


(2004)

A. Stress in nickel can be induced by almost anything, but one surefire way of doing it is to add chloride. Sulphamate nickel has been designed to offer low stress deposits, but you can always use high sulphate and/or high chloride baths.

For hard materials, probably the hardest is hard chromium, although you can also get hard electroless nickel with a high phosphorus content. You certainly cannot electrodeposit pure tungsten, (although there are some claims you can) but you can deposit binary systems using tungsten and (say) chromium or other metals. If you want to deposit pure tungsten, try vacuum technology; this will also let you put down tungsten nitride, which has a hardness well in excess of 2,000 Hv. Perhaps you would like to tell a bit more about what you are doing?

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK


(2004)

A. I think that he is looking for sodium tungstannate, which is added to nickel plating solutions to increase the hardness. Twenty years ago, there were several articles and formulas in print. I am fairly sure that it is still being used in some brush plating solutions, with a very limited build up possible -- i.e., a cap coat.

James Watts
- Navarre, Florida


sidebar









sidebar









sidebar
September 13, 2013

A. Electroplating of Tungsten is quite simple actually. Ideally, the material should be bead blasted.

1. Reverse electroclean, periodic- 3 seconds at a time 5x @ 5 volts.
2. rinse
3. reverse sulphuric acid (Type II anodize tank may be used) for 5 seconds at 8 volts
6. rinse
7. Nickel chloride strike (live entry) @ 5 volts for 20 seconds (periodic- 5 seconds at a time).
rinse
8. EN plate or copper or whatever you need to do.

Jeff Mills
- New Gloucester, Maine USA

September 2013

thumbs up signHi Jeff. Thanks. Someone is going to have to invent some new vocabulary for the electroplating industry. We are back to different interpretations of the phrase "can be electroplated" . . .

Trevor, James, and myself assumed that Michael was inquiring about electroplating of tungsten onto a substrate of something else, whereas you have assumed he was inquiring about electroplating of something else onto a tungsten substrate :-)

Regards,

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


September 15, 2013

A. Ok Ted. My mistake. Sorry. ;-)

Jeff Mills
- New Gloucester, Maine, USA

September 20, 2013

A. Hi,
I am new student to this fascinating science.
I believe the correct term is electrodeposit, e.g., "I want to electrodeposit W".
Cheers,
Adib

ADIB KASHANI
- Perth, WA Australia

September 26, 2013

thumbs up signThanks Adib, you're absolutely correct! Consistently using "electrodeposition of" and "plating onto" would fix that confusion.

Regards,

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


September 23, 2013

A. Tungsten can be plated from a melt of sodium tungstate with a small addition of sodium pyrosulfate. Temperature 1650 °F

Bill Zweig
- Vancouver, BC, Canada



January 30, 2014

Q. Hi All

I have a problem that would be solved if I could electrodeposit W on Copper.

But perhaps someone could guide me to an alternative solution please?

I need to have a small bead of mercury spinning in a channel made of copper with a coating of some metal that won't form an amalgam or degrade the mercury and have similar electrical properties to Tungsten and Copper.

Any ideas perhaps?

Kind Regards

Trenton Carr
- Pretoria, Gauteng, South Africa


January 30, 2014

A. The electrical properties of nickel are not too far from tungsten. Nickel can be easily plated on copper, and, I believe, will not amalgamate with mercury at ambient temperatures.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg,
      South Carolina



Would an electrodeposit of Ni-P-W on Cu prevent the formation of an amalgam if in permanent contact with Mercury?

February 10, 2014

Q. Hi All

I need to have a bead of Hg spinning in a Cu channel plated with some material that has similar electrical resistivity to Cu [ (20 °C) 16.78 (ed. note: units unintelligible) ] but that will not form an amalgam with, or degrade the Mercury.

Tungsten is a candidate (52.8 [ed. note: units unintelligible]) but it's difficult to deposit on its own in a complicated molten salt process beyond my cost target. Therefore co-deposit appears the only viable option, but I'm worried about the Ni in the alloy being amalgamated over time.

If so, would the P-W keep its structure? If it does, would it be possible to "pickle" the Ni-P-W and then use fresh Hg for the rest of the application?

The Hg and plated Cu channel can be operated in an inert gas environment if needed and I'm looking for a 10 year operational life.

Possible answers are pay-walled to me.

Thanks

Trenton Carr [returning]
- Pretoria, Gauteng, South Africa


Electroless Plating
Mallory & Hajdu

February 2014

A. Hi Trenton. Access to Finishing.com is free, but if you have found papers on another site which require payment to view, we can't help with that.

You can do an electroless deposit of Ni-P-W alloy with up to 20% tungsten according to Mallory & Hajdu =>
Gawrilov's "Chemical (Electroless) Nickel Plating" [link is to product info at Amazon] very briefly mentions electroless Ni-P-W alloys. Brenner's "Electrodeposition of Alloys" has a whole chapter on tungsten alloys, but that 1400-page tome is so exhaustive that I don't have the necessary several hours to study it and summarize :-(

Iron is notable for not forming amalgams with mercury. Could the copper be plated with iron, kept in an inert gas environment, and maintain low enough resistance to convey the electricity to the copper channel?

Regards,

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


February 11, 2014

thumbs up signHi Jeffrey

I've been advised that only Iron and Tungsten are not amalgamated, thank you for your reply.

Hi Ted

Paywalled not by finishing.com but by other technical paper repositories, and I'm not asking for help to circumvent that, but perhaps for a solution to my problem from someone with that knowledge.

I'm going to try Ni-P-W on Cu and pickle that in Hg to see if the Ni is amalgamated out the alloy. The process is cheap. Might also try some Moly.

The resistivity of Iron is too high.

Another option for me (and by the look of things, the best) is to try CVD Graphene on Cu, but once more, I cannot find any info on the interaction between the two.

Thank you for your reply.

Kind Regards

Trenton Carr [returning]
- Pretoria, Gauteng, South Africa



Electroless plating of tungsten onto alumina

July 22, 2015 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Can tungsten be plated on alumina? Electroless or other means.

Thank you!

Jean Bedard
- Montreal, Qc, Canada


July 2015

A. Hi Jean. I think a PVD vacuum process would be necessary. I'm not aware of electroless tungsten and strongly doubt that it is possible (but see the earlier entries about alloys). Good luck.

Regards,

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



December 30, 2016

Q. We have a China supplier who is plating 4140 steel with tungsten. They seem to struggle with achieving hardness levels (750) we desire. Please comment on the process.

jerry priest
b.k. thorpe co - long beach, California


December 2016

? Hi Jerry. Can you tell us anything about what they are doing -- like thickness, purity, method of application? What the component is so we can visualize whether line of sight methods are useable, the criticality of thickness distribution, etc.? Maybe it would be ideal if the shop doing the work described the problem? Thanks.

Regards,

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


simultaneous January 1, 2017

A. Hi Jerry
Tungsten coatings are unusual whereas tungsten carbide or tungsten nitride are common. Both are used as wear resistant coatings which is related to hardness but not directly equivalent. These coatings are only a few microns thick and hardness is impossible to measure by standard methods. In effect, you are measuring the hardness of the base metal.
So my question is - why and on what basis do you specify hardness.
And 750 what? I guess VPN but guessing is not a good quality tool.

geoff smith
Geoff Smith
Hampshire,
       England



January 1, 2017

A. Jean,
W can be painted onto alumina, it's quite common.
Jerry,
How is the coating thickness? Thin coating can be a cause and one may wish to test parts that have been sitting out building up an oxide layer as opposed to parts fresh out of a cleaning solution or oven, etc.

blake kneedler
Blake Kneedler
Feather Hollow Eng.
Stockton, California



December 30, 2016

Q. As comment this is our second supplier of tungsten coated rods. First supplier is limited on size range hence we move to a new supplier. You do not get "straight" answers from the Chinese suppliers. Perhaps language or simply they figure you do not need the detail or information. They struggle with achieving thickness and tensile. Previous supplier polished the tungsten surface and this seemed to work harden the material to acceptable level.

27089

jerry priest [returning]
b.k. thorpe co - long beach, California

ADD a Q or A to THIS thread START a NEW THREADView This Week's HOT TOPICS

Disclaimer: It is not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & DevicesUsed & Surplus


©1995-2017 finishing.com     -    Privacy Policy
How Google uses data when you visit this site.