Home
 
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
SEARCH🔍
the Site
no_pop_no_spam2

World's top finishing resource since 1989
Chime right in - No login req'd

topic 2480

Which substitute for hard chromium plating?

Current question and answers:

Ed. note: No abstract questions
Please, please, pretty please!!

February 2, 2021

Q. Hi
I wonder what process can replace technical chrome plating.
Workpiece: cylinders, pistons

Aukasz Potocki
- Bydgoszcz Kujawsko pomorskie
^-- Answer or Comment on this question --^
none
adv.
this text gets replaced with bannerText
spacer gets replaced with bannerImages




Previous closely related Q&A's starting in:

1998

Q. We need either assistance or at least some guidance. We are a metal finishing machinery manufacturer. From time to time, we need to have machinery driveshafts chrome plated. This is done primarily for abrasion resistance purpose. Once chromed, the shaft is ground for smoothness (one surface contacts a rubber grease seal, so it must be very smooth). The process produces a reliable driveshaft component. The problem is that it has been difficult to find good chrome plating service and once found, it is (or soon becomes) very expensive. Quantity is around 25 shafts/year, each one being about 10-12" long with approximately a 2" O.D. shaft connected to a 6-10" flange.

The question is this - for our application, is chrome plating really the best approach? If so, great - we'll just have to keep finding ways to reduce costs. If not, what else should we consider?

Dan Regan
mechanical prep specialist. - Cinnaminson, New Jersey
^-- Answer or Comment on this question --^


1998

A. Dan,

A. You might want to consider some of the PVD hard coating options.

Donald M. Mattox
Society of Vacuum Coaters
Albuquerque, New Mexico

Ed. note: Mr. Mattox is
               the author of -->



A. Dan: While you might want to look for a substitute on the environmental basis of trying to minimize chrome plating when possible, I strongly doubt that you will find PVD less expensive. And as long as you already have found chrome plating to be highly suitable for this function, I don't think you'll find anything that functions as well (or better).

When it comes to machinery with lubricated rubber seals, it's not solely a question of smoothness and coefficient of friction, but of oil-retention properties--and due to the "dried must-flat" topography of hard chrome plating, it excels at all of these.

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


1998

A. Some thoughts,
Electroless nickel has many of the same properties that you are looking for and probably would be cheaper in the ones and twos quantities. Another plus is you would only have to pre grind, post grind would not be required. Drawback is thickness. The practical maximum thickness for EN is 0.0015". This probably will not have the length of service that the chrome will.

Also, you can regrind and rechrome the shaft a great number of times.

What probably is killing you is the minimum lot charge. You could very probably have two or possible even three shafts done for the price of one. This would mean that you would have to keep inventory longer than you might like because of several size shafts used.

Your shaft is about the easiest size and shape that there is to chrome plate if your plater is using conforming electrodes. A good plater, after a learning curve of a few parts, could cut your "for grind" thickness to one or two thousandths which would save you several dollars per part on the grinding operation.

If you had parts on the shelf, you could find an excellent plater and afford to ship anywhere in the USA, in lots of say 5, and have significantly cheaper per part plate and grind cost. My nickel says that you would have higher quality product also.

James Watts
- Navarre, Florida



To minimize search efforts and to offer multiple viewpoints, we combined previously separate threads onto this page. Please forgive any resultant repetition, failures of chronological order, or what may look like readers disrespecting previous responses -- those other responses may not have been on the page at the time :-)



Non-porous Alternative to Hard Chrome Plating

2002

Q. I am working on an improvement to a spool valve that has a sealing issue when controlling the flow of RTV silicone. The spool is 17-4PH with a .0008"-.001" hard chrome plating that is then centerless ground down to the finished diameter. I believe the porous chrome is absorbing some water from the atmosphere, dragging it through the seal into the valve body and allowing some RTV to cure (the RTV is moisture accelerated) on the surface of the valve stem. This cured RTV is being dragged through the seal causing its eventual failure. What is a very non-porous, hard, smooth finish that I could use on the valve stem to keep moisture from being carried through the seal into the valve body?

Mike Vidal
- Lincoln, Rhode Island
^-- Answer or Comment on this question --^

simultaneous 2002

A. Hi Mike. I'd suggest looking into Electroless Nickel Plating.

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


2002

A. You did not say how hard, nor what the stress variables might be, however,

Sulfamate Nickel can be plated to any thickness and ground back PORE free. It can be hardened with an organic additive however with this method of hardening you cannot stand much high temperature as the occluded organic will out gas. It can be hardened by co-depositing cobalt with the nickel, and then you can grind back and go as hot as you desire.

Come back with some more data and let's talk again.

robert probert



Robert H Probert
Robert H Probert Technical Services
supporting advertiser
Garner, North Carolina
probertbanner


2002

A. I agree with the previous responses. Indeed, EN or sulphamate Ni are less porous than chrome, although your problem might go beyond this and not be solved by switching to a different plating. Can you keep the stem dry by means of drying its surroundings? Can either be hot lamp, hot air, etc. This will be better approached using some sort of a jacket or sleeve. Then you might want to consider teflon (plain or impregnated in a plating) to cope with the possibility of problems due to lack of lubrication.

Guillermo Marrufo
Monterrey, NL, Mexico


2002

A. Mike,

A good deposit for this is electroless nickel as stated above; it is as deposited glass-like (amorphous), and can be baked to almost as hard as Hard Chrome.

Chris Snyder
plater - Charlotte, North Carolina



Properties of Hard Chrome

2002

Q. Can you quote some typical hardness levels and adhesion strengths for hard chrome. The applications that I am interested in is the use of this process for build up bearing seats of internal gears.

Paul Leslie
coal - Moranbah Qld Australia
^-- Answer or Comment on this question --^

2002

A. When properly applied, adhesion of hard chrome to most low and mid alloy steels is around 20,000 psi or more. Vickers Hardness will be around 900-1100 HV (approx. 67-72 Rc). But if the gears are surface treated, specially nitrided, getting a good bond can be challenging even for most experienced platers. Remember that chrome is also brittle (less than 2% elongation). You can also consider nickel as an alternative.

Guillermo Marrufo
Monterrey, NL, Mexico



To minimize search efforts and to offer multiple viewpoints, we combined previously separate threads onto this page. Please forgive any resultant repetition, failures of chronological order, or what may look like readers disrespecting previous responses -- those other responses may not have been on the page at the time :-)



Alternate coating for molds

2006

Q. I would like to know any possible alternatives to hard chrome plating for plastic injection moulding dies. As one might agree hard chrome has problems like low throw, no plate in extremely low current density areas and high current density burning or overgrowth. Any suggestions regarding latest practices/trends will be appreciated. Will nickel/cobalt, teflon imp.electroless nickel perform equally good as hard chrome. PLEASE ADVISE.

Thanks in advance,

vikram dogra
Vikram Dogra
Irusha India - Chandigarh, India
^-- Answer or Comment on this question --^

balesmss banner


2006

A. Electroless Ni-P or Ni-B based composite coatings will be a useful alternative to hard chrome for plastic injection moulding dies. The performance of these coatings will be equally good as that of hard chrome.

According to some published literature, a 50 micron thick electroless Ni-P-SiC coating could improve the life of molds (usually last for 10000 moldings) for plastics, rubber etc., by 15 times. Electroless Ni-P-SiC coatings could prevent accelerated corrosion of abrasion molds in the plastics industry and in this respect it is superior to chrome plating. In foundries, electroless Ni-P-SiC coating enables an easy release of sand cores without breakage from core boxes.

Electroless Ni-P-PTFE coatings offer non-stick, non-galling, higher dry lubricity, low friction, good wear and corrosion resistant surfaces. Electroless Ni-P-PTFE composite coatings could also be used for molds for rubber and plastic components. The coatings can be used under a wide range of temperatures from cryogenic to 290 °C.

T.S.N. Sankara Narayanan
T.S.N. Sankara Narayanan
- Chennai, Tamilnadu, India
(ed.note Nov. 2017: The good doctor has a fascinating blog at https://advancementinscience.wordpress.com)


2006

A. Vikram,

You should use electroless process. Then you do not have to worry about low throw, low & high current density areas, etc.

High Phos (9-12%) Electroless Nickel with post plating bake is what you should do.

Thanks

Ken Katakia
- Ontario, Canada


2006

A. Very well answered by the other two respondents, I couldn't agree more. Only to add that electroless nickel, either composite with particles or heat treated, will require some special pre-plating techniques with some mold materials (like high alloy, stainless and copper alloys). Also special chemicals to strip it when required for modifications, repairs, etc. Chrome has been around for much longer, so it will be easier to find. Electroless nickel is a specialty that only found wide commercial use during the past 30 years in developed countries, composite EN maybe 20. So it will be harder to find in emerging regions.

Guillermo Marrufo
Monterrey, NL, Mexico



To minimize search efforts and to offer multiple viewpoints, we combined previously separate threads onto this page. Please forgive any resultant repetition, failures of chronological order, or what may look like readers disrespecting previous responses -- those other responses may not have been on the page at the time :-)



Hard Chrome Replacement Technologies

2007

Q. One of our customers has enquired about specific hard chrome replacement technologies. I was just wondering if anybody out there has had experience with, or has commercially available either "Amplate" Nickel-Tungsten-Boron alloy plating or "Takada" Nickel-Tungsten-Silicon Carbide plating.

I have read several articles on the internet about the coatings, including the patents, all of which look favorable, but nothing beats people's actual experience.

This is an Aerospace enquiry, we are notoriously slow to change so don't expect any work in the near future! At this moment we are in the design stage and are looking at various available technologies, but obviously if the process is not commercially viable then there is no point taking the query any further.

Thanks for any help or advice.

Brian Terry
Aerospace - Yeovil, Somerset, UK
^-- Answer or Comment on this question --^

2007

A. These finishes have received "preliminary evaluation" as feasible alternatives by some US firms that have multiyear government contracts to investigate chromium alternatives for the military. But as I attend the presentations on chromium replacement technologies year after year I am reminded of a notepad block my brother-in-law gave me for Christmas a few years ago "Consulting: if you're not part of the solution there is good money to be made in prolonging the problem" :-)

They're probably actually trying, but I hope you find someone who is actually using these because I think we'll make little real progress until private enterprise starts widely applying these coatings to some non-military parts and getting some service history.

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


2007

A. In certain applications and according to some specific and controlled testing, electroless nickel composite with diamond or other super hard particles with a subsequent heat treatment for maximum matrix hardness has demonstrated to be even superior to hard chrome. Being a plating process, makes it a promising candidate as opposed to other techniques that have limited adhesion and require a different surface preparation, such as HVOF. Only problem is that it is much more expensive and also in the line of fire of EPA.

Guillermo Marrufo
Monterrey, NL, Mexico


2007

Q. Thanks Ted and Gullermo,

Our current contract calls for the company to look at specific coatings but there is certainly no harm in suggesting other potential coatings.

As always Ted you are on the money with availability of these coatings. Unless commercial manufacturers can be persuaded to use these novel solutions then we have little hope other than to pay ridiculous premiums for coatings without a proven history.

Guillermo, is the electroless nickel diamond composite commercially available? A quick search doesn't reveal too much. As I said above we cannot afford to get caught in a situation with limited supply and ridiculous costs.

Thanks again for your help.

Brian Terry
Aerospace - Yeovil, Somerset, UK
^-- Answer or Comment on this question --^

2007

A. Electroless nickel + synthetic round diamond is a more accurate description of this hard chrome competitor and, to my knowledge, is a proprietary process only offered by Surface Technology, Inc. in NJ. Maybe you could find platers doing EN with other types of hard particles. Fully hardened plain EN (preferably boron reduced) could modestly compete in some environments.

Guillermo Marrufo
Monterrey, NL, Mexico


To minimize search efforts and to offer multiple viewpoints, we combined previously separate threads onto this page. Please forgive any resultant repetition, failures of chronological order, or what may look like readers disrespecting previous responses -- those other responses may not have been on the page at the time :-)



Need Wear Resistant Coating for Aluminum - Preferably Hard Chrome

2007

Q. Hello,

I work for a small company near Vancouver BC Canada and we would like to use aluminum in a plain bearing application. We are looking at getting a very wear resistant surface treatment for the bearing surface. I had hard chrome suggested as "the best" surface treatment for the application. I am unable to find a company that perform such treatments as well as differing answers as to why it is not a common practice (from attack of alloying elements by the chromic acid to "just because" and numerous things in between).

If anyone could suggest any or all of the below:

1)Local company we can build a relationship with to do the work
2)Comparable alternatives to hard chrome
3)Technical Resource on the subject
4)Explanation on why hard chroming is not performed on aluminum

Thank you and best regards,

David Coles
Product Designer - Surrey, BC, Canada
^-- Answer or Comment on this question --^

affil. link
"Hard Chromium Plating"
by Guffie
from Abe Books
or

or
see our review

September 2013

A. Hi David.

4). Hard chrome plating is rarely done on aluminum because aluminum is not hard. Surface hardening procedures like chrome plating are of limited value on soft substrates because the plating may simply crack like an eggshell under heavy loads when there is no hard support under it. But it can be done.
3). For a quick intro, please see our on-line FAQ, "Introduction to Chrome Plating". For greater depth, Guffie's "Hard Chromium Plating" is good =>
2). Aluminum is probably not a good bearing material because it galls badly, and aluminum on aluminum would be a horrible bearing. Aluminum is frequently electroless nickel plated, which is a hard coating which might possibly suffice for certain bearing applications, but the electroless nickel plating can be infused with teflon particles, which would probably make it a good bearing material.
1). Sorry, I don't know which is any local shops offer hard chromium plating on aluminum.

Good luck!

Regards,

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

Q, A, or Comment on THIS thread SEARCH for Threads about ... My Topic Not Found: Start NEW Thread

Disclaimer: It's not possible to fully 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 & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact    -    Privacy Policy    -    ©1995-2021 finishing.com, Pine Beach, New Jersey, USA