Hard Chrome Plating vs. Plasma, HVOF, Flame Spray

A. Hi Muragendra. We discuss technology in this forum rather than brands & sources and their claims ( huh? why?). SureCoat is a proprietary coating, but MTS says it's a flame spray coating, so we can at least discuss flame spray coating.

On their actuators, yes, it replaces hard chrome plating. You can google 'flame spray' or search for flame spray videos on youtube. In many cases these days flame spray coatings can successfully replace hard chrome, especially when the coating is required on an outside diameter: the adhesion is not "perfect" like chrome plating can be, but it is good enough, and the porosity is very low so the corrosion resistance is good, and the wear resistance (in general) is quite a bit better than hard chrome.

It generally requires a robot to apply which, along with some other factors like machining cost, can make it quite expensive. But for a captive shop processing enough parts to justify a robot, and of a limited enough range that machining setups and programming costs for the robot are not a major factor, it could be that it's not significantly more expensive than hard chrome plating.

Luck & Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 2021

Thank You very much sir

Muragendra Magadum [returning]
- Pune, India
November 15, 2021

A. Since I am not an expert in chrome plating in any manner, I can only repeat what I have heard from people who have done some work in plasma spray and HVOF. There are several issues with plasma-spray methods: inconsistent or poor adhesion, high temperature application leading to tempering of steels, high cost of set up, applications to limited shapes like shafts, low throughput. Plasma-sprays are probably more suited to applications of other hard coatings like carbides on heavy duty, large shafts and similar heavy but less complex-shaped items. Refurbishing/repairing of worn parts remains the main application. Requires post machining. Consequently, it is not favored as a replacement for hard chrome electroplating. Anyone else has more info or corrections to add?

Mandar Sunthankar
- Fort Collins, Colorado
1998

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A. Dear Mr. Lalit Shaunak,

I have worked with Atotech India and they have an excellent product for your particular concern.

HEEF 25 or HEEF 40 is specially for wear resistance and corrosion protection in commercial practices and it is world wide success.

you may contact their Haryana works or Delhi sales office and also they have some technical executive placed at Mumbai and Pune.

Yours,

Hemant Kumar
- Florida, USA
1998

A. Hi Gupta. Not exactly the kind of technical, non-commercial reply I asked for :-)
Surely you can refer me to a technical article supporting that claim.

Luck & Regards,

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

A. Hi Mohammed. The AESF (www.nasf.org) has an annual Airline & Aerospace Conference that often has papers comparing these two finishes. Contact the AESF bookstore about buying copies of the proceedings.

Some newer finishes have great wear resistance and fewer environmental concerns than hard chrome plating, but currently they are more expensive and line-of-sight only.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2001

A. Hello Mohammed!

In addition to the AESF, you'll also want to check out the Hard Chrome Alternatives Team. HCAT is a joint US-Canadian Defense services project, looking to replace chromium electroplating with HVOF thermal spray, and they've done a lot on coating and testing.

Good luck!

Lee Gearhart
metallurgist - E. Aurora, New York
2001

A. You may get the information straight from the guy heading the effort for the U.S. Defense Dept. He is at the Naval Research Lab and he could e-mail the papers or refer to a website.

Mandar Sunthankar
- Fort Collins, Colorado
2001

 Both sides fail to tell the complete truth and hide behind poor or bad science and draw conclusions that are some far reaches. Consider them to be used car salesmen with law degrees that are now scientists. Both chrome and HVOF have some things that they do better than the other. Reality is that plasma is generally better than flame spray and HVOF is generally better than plasma. Dual arc can beat HVOF for a few applications. It all depends what your requirements are. NO magic solutions.

James Watts
- Navarre, Florida
2001

A. SHAH,

DO YOURSELF A FAVOR. CONSIDER ELECTROLESS NICKEL IN THIS APPLICATION. WE DID HARD CHROME PLATING AND VERY SUCCESSFULLY SWITCHED THOSE CUSTOMERS OVER.

Ray Delorey
-Cambridge, Ontario
1998

A. I don't understand why there is so much discussion about HEEF and electroless nickel when the question was about HVOF's possibility as a chrome alternative.

Regardless, I'm no expert on HVOF, but I am aware that at least in the aerospace industry the HVOF technology is getting quite a bit of money spent researching its applicability. It appears to be the most promising hard chrome alternative at this time.

As was this year, at next year's AESF Aerospace Finishing Forum, a Hard Chrome Alternative Team (HCAT) will meet in conjunction with the forum, and HVOF promises to probably be the highlight. If you are seriously interested in the latest HVOF research, I would make plans to attend. It will be in April 1999 in Jacksonville, Florida.

sandi geheb
- Navy.mil
1998

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1998

A. Dear Mr. Lalit Raunak Shah

Processes such as HVOF are used to apply coatings that can outperform chrome plating .

Depending on the compositions selected and the process used the performance of the coatings will be as good as Chrome plating at similar cost to much better than chrome plating at higher costs but may offer better value.

The selection of the coating composition and process will of course be application specific.

Thanks
Anand

Dr. K. Anand-
- Bangalore, India

A. I have only a couple of things to add to this discussion. I have been involved in replacement of Cd and Cr coatings for a few years now. If fact, while serving as an active duty Air Force officer, I was a key founder and the first chair of the Hard Chrome Alternative Team (HCAT). While the team is currently looking primarily at HVOF, it is important to keep a fundamental approach in mind. Coating replacement is EXTREMELY application dependent. The reason HVOF is getting so much attention at the HCAT is because the teams primary application was aircraft landing gear. Many applications and industries do not require the performance of a HVOF coating and/or can't afford the process or the development. In many cases electroless nickel, trivalent chrome platings or nitrocarburizing makes more sense. So, the initial question should not be if HVOF is a viable alternative to hard chrome, it is. The question should be is it the "right" (in terms of cost, performance and requirements) alternative.

John Farraro
an aerospace company - Troy, Ohio
1998

A. Dear Mr. Lalit, We are very active in the marketing of Oilfield Services particularly hard chrome plating, specialized maint. & repair welding, electroless nickel, nickel, thermal spray (powder & wire), plasma transferred arc and the HP/HVOF.

My experience is that the HVOF is a relatively new process here in U.A.E. But the results are wonderful. I am a specialist in coatings and have found that HVOF scores fairly high over chrome plating. Still chrome plating has its charm and that is the price and dense quality coatings with high finish. However, with a diamond wheel HVOF also gives a equally top quality finish. Bond strengths are claimed to be in order of 10,000 psi. Same is still to be tested in this part of the world. My opinion is that HCP is not over yet but considering the alloy range in HVOF, the HVOF is going to be there for years to come and will be the leader in coatings.

K. Jaishankar
- Abu Dhabi, U.A.E.
1999

A. Mr. shah,

We offer the HVOF technology and consumables for suitable coating replacing Chrome Plating.

In fact, on 17th of Oct '03, we are launching the Pune Chapter of Indian Welding Society, where I am going to talk about replacement of chrome plating with HVOF coating methods. Already many users are shifting from chrome plating to HVOF coating methods because of the environmental factors and HVOF coating showing better anti-wear characteristics.

Shashi Bhushan
- Pune, Maharashtra, India
2003

A. HVOF tungsten carbide + Ni-Cr matrix properly sealed is the standard for applications where extreme abrasion, erosion and corrosion is found.
The disadvantages are expensive materials and sophisticated diamond grinding and/or lapping required to attain the required finish.

Guillermo Marrufo
- Monterrey Mexico
February 24, 2017

Q. Hi Mohammad,

The main benefit is that hard chrome plating uses a highly toxic chemical and Plasma spraying doesn't.

Chromic acid is also considered a Substance of Very High Concern (SVHC) in the European Union (EU) and its use is highly regulated, with most of the EU countries wanting a complete ban on its use.

So, what makes chromic acid so disliked? Well, not only is it toxic, it also causes cancer, can cause birth defects, can cause skin sensitisation, can ulcerate the skin (nasal septum perforation used to be common in chrome plating operatives, before it was understood what caused the problem) and on top of all of that, it is highly toxic to the environment.

With plasma spray, which I acknowledge, is considerably more expensive, all of that goes away!

Brian Terry
Aerospace - Yeovil, Somerset, UK
August 19, 2019

A. Dear Mr Mohammad

It is a national given mindset: the cheapest option is the only logic.

Safety, health, environment all are secondary in developing nations. We don't even begin to think about these aspects.

The economic maturity of nations is the seed for progress of thought and choice.

I wish we could reinvent our thinking from cheapest to safest.

4
Khozem Vahaanwala
Saify Ind

Bengaluru, India

December 6, 2019

A. There could be a misunderstanding in the last question of Mohammad Mushtaq.
The preferred replacement for hard chrome is HVOF Tungsten carbide. Besides the environmental and health issues mentioned, it is specified because it is at least three to four times more wear resistant. It requires a binder of either Cobalt or NiCr.
To my knowledge, there is no such thing as Plasma chrome around. There are chrome compounds such as chrome oxide or chrome carbide that are sprayed for special applications requiring hot hardness or a particular chemical property of chrome.

Guillermo MARRUFO
- Monterrey, Nuevo leon, Mexico
April 2, 2020

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Ed. note: Thanks Guillermo, your insight makes the thread a lot more understandable.