Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Teflon coating of stainless steel
Current question and answers:
Q. Lately, I've been searching for methods of how to coat a metal sheet with a material that has non-stick properties and a good abrasion resistance.
Thinking about this, I came up with the idea of coating the metal with Teflon (PTFE), or another similar fluoropolymer. Maybe through an electrostatic spraying process, or a fluidized bed coating.
Someone could help me with this? Help me with ideas of how can I do this, and what equipment I need to accomplish this objective.
The metal sheet does not suffer mechanical effort, the temperature of work is about 40 °C.
Student of Mechanical Engineering - Morro da Fumaça / SC / Brazil
July 22, 2021
A. Hi Pedro.
• If it's one sheet for personal use, you probably want to search for a jobshop which offers this service, although high temperature silicone can be bought in a spray can, and just might be good enough for your needs.
• If your interest is a mass production factory, either for real or theoretically as a student project, I think you will find the following pages interesting because they quickly & simply explain the 3 steps that are always involved, as well as introduce some variations in those steps based on whether the teflon will come from a water based liquid, a solvent based liquid, or powder coating:
https://www.coatings.co.in/teflon-coating-process-india/
https://www.coatingsolutions.com/dupont-teflon-coating-process/
I have seen nylon coatings applied via fluidized bed but I don't personally know whether Teflon, with it's higher temperature requirement, is amenable to that process. In fluidized bed coating, air is blown up from the bottom into an open topped tank full of powder, making the powder act like a liquid or quicksand; then heated metal parts are dipped into it and the powder melts onto them. It's generally used for things like wire goods where full coverage with electrostatic spray is difficult; sheets are usually done with electrostatic spray.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 2021
Q. Hello Mooney,
I appreciate your response to my question, but since I posted on this topic, I've been working 6 hours a day on this subject, as my internship job.
I've found out that in all cases of PTFE or PFA coating, it uses a first layer of primer, in some cases even other layer or compounds that are unknown to me.
So now, I'm looking for a light on what primers are used, for each corresponding top coating.
As a personal wish, I would like to make contact with you, I've found out that you are a flawless professional, especially on this matter.
:)
Student of Mechanical Engineering - Morro da Fumaça / SC / Brazil
July 26, 2021
A. Hi Pedro. Thank you for the vote of confidence, but actually I have no personal knowledge of Teflon coating -- and as part of my agreement with the suppliers and consultants who make finishing.com possible by advertising here, I have committed to making no private comments at all; anything I have to say must be said in public.
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 2021
⇩ Related postings, oldest first ⇩
Q. I work in a watch company and we are having a problem with one of our straps. The strap is made of 316L stainless steel and is sandblasted with a special blend of coloured sand to achieve a matte and grayish finish. The sandblasted pieces were coated with a very thin layer of PU (polyurethane) coating.
The problem with this finish is scratches show up very easily, which our customers don't like. One solution from our vendor is to coating the pieces with a thicker PU coating but the straps are shinier than before. I'm not sure whether the coating really helps to reduce scratches, or the scratches are just less obvious on such finish. What are the advantages and disadvantages in such an application?
- Hong Kong
2000
A. You can put a water based Teflon coating instead of a thick PU coating for your application. Water based Teflon coating is very easy to use. It produces a very thin layer of coating that has good wear resistance, non-scratchable, good chemical resistance and heat resistance.
S. Y. Yuen- Hong Kong, China
2000
Q. I work in a portable measuring instruments company, and we need to put PU coating on stainless steel, is there some special requirements for the part surface, and how about the process of PU coating and equipment? Thanks in advance!
Fei Peng- Shenzhen, Guangdong, China
2002
A. Hi Fei. In general terms, surface preparation is probably the same as for paint or powder coatings (cleaning, surface activation, and phosphatizing of some sort). But what is the objective of this coating please -- electrical insulation, appearance, tarnish prevention, chemical resistance? And what type of measuring equipment is it -- micrometers (probably only very mild corrosion resistance needed), transits (moderate environmental exposure), weather recording (very severe exposure), etc? Please try to give us as targeted a starting point as practical. Thanks!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2002
Q. I'd like to manufacture a product in SS306 and I want to coat it with Teflon coating.
My condition is: The SS tube with OD 4.6 mm and length 310 mm. I'd like to coat Teflon coating thickness of 20 microns on OD throughout length.
Purpose: Anti corrosion, non conductivity of heat and non conductivity of electric current.
Area of application: Pharmaceutical / Surgical.
Questions:
1. Please let me know the best method of Teflon coating considering my area of application.?
2. Is there any specification for Teflon coating, surface finish, hardness, etc.? If so, what purpose it will be used?
With regards,
- Coimbatore, Tamil Nadu, INDIA
A. Coating the OD is absolutely no problem. Typical two coat Teflon coating is 35 microns ± 10 microns. Lower thickness can be archived with good coating practices.
It will serve the purpose of anti-corrosion, heat transfer and electrical insulation (to some extent only).
However, if the application is surgical, then Dupont specifically restricts use of Teflon®. Prior clearance will be necessary from Dupont on selection of grades and the application process.
Hope this helps you.
Mohali, Punjab, India
2003
Q. I want to coat teflon on stainless steel. What are the different factors to be considered while coating. How can I analyse the coating is good or bad. You can send as many followups as you want. I want to go into details and will pursue this topic for more than one year.
Rag [surname deleted for privacy by Editor]Anurag - Pune, Maharashtra, India
2006
A. Hello, Rag. The first detail to provide, please, is what you are trying to accomplish and with what kind of parts. If you are trying to teflon coat stainless steel powder for chemical resistance, that might have little in common with trying to coat stainless steel tank cars with teflon to eliminate the need for polishing. So let's start those followups.
Since you are seeking general education, and have more than a year for the investigation, you might also browse through these specialty books on the topic.
Luck and Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 18, 2008
Q. Hello,
I need to coat a SS-316 rod (currently coated with epoxy powder coating) of 60 cm length & 6 mm dia with Teflon, over the powder coating.
I need to use it for a prototype design.
It should meet the following demands
- Environment of application is oil & salt water
- Need to get electrical insulation
- Need to know how long it will last, if it is used in a water flow region?
- What should be the coating thickness to withstand such a rough condition?
student - India
|
A. Try PEEK Coating instead. William Maghen- Bayan Lepas, Penang, Malaysia November 10, 2009 Thanks William, but your 4-word response is too brief :-) Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey June 27, 2010 |
Q. I am interested in a thin coating of a low coefficient of friction material for stainless steel sheet metal, to prevent metal to metal contact and act as a smooth surface when components are slid against each other.
Minimal load bearing on the surface.
- West Berlin, New Jersey
June 1, 2012
A. Depending if it has to be permanent and very long lasting or is only for occasional contact and short periods the possibilities are so vast and range from the cheapest special greases to mid-cost treatments like Teflon spray, to more expensive platings to the most expensive and exotic composites deposited by PVD, CVD, Thermospray, Plasma, etc.
Guillermo MarrufoMonterrey, NL, Mexico
June 25, 2012
A. Teflon adhesion to stainless steel is a problem. However, it was sorted out when Gillette introduced their Teflon coated razor blades and put down an interlayer of Pt-Cr onto their stainless steel blades. This is well patented and documented, but in essence, the process involved vacuum deposition of the Pt-Cr followed by spray coating and sinter polymerisation of PTFE. The adhesion mechanism is believed to go through a Cr-F complex structure, although I am not sure of its details.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
June 30, 2012
Q. Can we coat Teflon coating of 70 microns on SS304 material? If so what is temperature that needs to be maintained for curing?
R.Ramakrishnan- INDIA
January 31, 2013
Thin Opaque Dip-able coating for stainless steel
Q. A handful of years ago I was shown a thin, dip-able coating applied to a stainless steel bicycle spoke which was opaque, had very good color, and was so thin that cleanly coated the fine threads of the spoke allowing the nipple to thread on without issue. Even white was very bright with no stainless showing through, on a coating that seemed to be microns thick. We chose to go another direction and I've not thought about it again until recently as I need a thin disable coating for a part with threads.
Supposedly the finish was 'sol-gel' and was being performed in Taiwan and was commonly used in manufacturing electronics, that is really all I remember about it.
Now, I've been involved in composites manufacture for a long time and am familiar with sol-gel processing for aluminum (Boegel, AC-130), but this is clearly something completely different.
Essentially, I need a very thin, dip-able cosmetic coating and can't for the life of me seem to figure out what what I'm actually looking for!
Many thanks in advance for your help
Product Engineer - Indianapolis, Indiana
March 3, 2014
A. Hi Josh. My understanding is that sol-gel coatings were most used for thin films on electronics in the beginning, but that they are now applied to glass, plastics, and metal as functional coatings. Although I have no real experience with them, it would not surprise me if you had seen TiO2 sol-gel coatings, as I'd expect them to be both white, and useful as a metal protector.
Although they are dip-able, I don't think I'd categorize them as low technology ... by which I suggest that competitive thin coatings that are not "simple dip coatings", like electrophoretic lacquering, PVD coatings, or anodizing may sound more complex but may actually be just as "simple" and inexpensive :-)
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 2014
Q. I would like to know how to give a teflon coating of 2-3 mm thickness outside a 40NB schedule 40 ss pipe, flanged at one end. Kindly advice if any enterprise is supplying the same for service as dip pipe for feeding 98% H2SO4 to treatment tank (many other chemicals are being added to tank, pH variation till 9 will occur during the process (maximum operating temperature 90 °C ).
I would have used just teflon, but there is a high speed agitator in the tank and I assume using just teflon pipe won't survive that turbulence for so long.
Thanks in advance
chemical industry - kerala, India
April 28, 2015
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. I work in a Gas control system company, and I need to put teflon coating on stainless steel 430F material , for avoiding corrosion as the part/assembly has to work on open environment and also it faces more than 250 °C temperature, hence the part gets easily corroded. and is there any alternate way to avoid corrosion please suggest if possible.
Basic need:
1)should avoid corrosion
2)coating thickness should be 5-10 micron (as part is too small)
GAS CONTROL SYSTEMS - PUNE, MAHARASHTRA, India
July 23, 2015
Teflon coatings on formed metal strips
Q. Hi All,
I want to add a teflon coating to a formed metal strip for a medical device, the strip comes in contact with the body. Can the teflon be added after^before the strip is formed, or will it crack?
Thank you in advance.
Wayne.
Engineer - Manchester, UK
April 27, 2016
A. It would be best to coat this after forming masking can be used. Also you need to be more specific than Teflon this is just a trade name for a range of products but I suspect you will be wanting the P.F.A powder over a primer.
Paul RennisonSurface technology - Leeds, Yorkshire, United kingdom
June 21, 2016
Q. I have a requirement of teflon coating (~40 microns or more) a SS304 cylinder of 11 mm outer diameter, 9 mm inner diameter, length 11 mm. Any schemes please ?
srinivasan Ranganathan- Hyderabad, India
November 5, 2016
Teflon Coating of Sintered Metal
Q. Hi,
Is PTFE coating possible in a sinter metal (mostly steel) part? I have a requirement like a housing made of SM processing needs teflon/PTFE coating.
- Tamilnadu, India
December 19, 2017
A. Hi,
The suggested process should not be a problem but keep in mind line-of-sight restrictions in terms of i.d. or cavity coverage, if applicable.
Blake Kneedler
Feather Hollow Eng. - Stockton, California
December 26, 2017
Q. I have to do PTFE coating on a 200 dia roller; my required thickness is 8 to 10 mm. Later it has to be milled for cavities used as a rotary moulding die. Is this technically possible and which is the best method?
Ajith ParakkuthB tech project - Chennai India
December 29, 2017
Q. I work with a company that manufactures and transports Oleum. We use carbon-steel for our storage thank; this normally produces hydrogen gas due to reaction with the iron. In order to prevent this, I suggested that we coat the carbon steel with PTFE (polytetrafluoroethylene).
Can you please suggest a very easy & effective method to coat the carbon steel and to what thickness? Thanks in anticipation.
Applied chemist - ibadan, oyo state, Nigeria
June 23, 2019
Q. Good Day
- Look forward to hear what is the best roller material in roll-to-roll flexible manufacturing to avoid the scratches (Polyimide side scratches). Customer is very concerned.
What type roller material is suitable for Chem at Higher pH (KMnO4+KOH)
EMS - Penang, Malaysia
April 2, 2020
A. Hi Prasad. Teflon coating would be resistant to those chemicals at reasonable temperatures and concentrations, but I'm not quite seeing the connection. Are you talking about cleaning the rolls with these chemicals, or are these additives present in the polyimide, or are you saying that this is a flexible manufacturing" installation that will also handle materials other than polyimide?
Please provide enough information so that those who are familiar with similar installations don't have to guess what roll materials & coatings you've tried and what weaknesses they have exhibited. If someone reads your posting hen takes the time to suggest something you already tried, it will waste both your time and theirs :-)
Plus, people less familiar with this technology like myself would like to learn from your posting. So details please! Thanks.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 2020
Q. As per one design application, I have a Block & Slider (both have to be metal based on the stresses they face). The slider rides over the block and gets locked. I'm exploring providing a PTFE/Teflon coating over the block to reduce friction.
Also this application exposes the block to certain hospital cleaning solutions. Kindly comment on the wear resistance (10 times sliding per day) of the coating and the longevity of the same.
- BENGALURU, Karnataka, India
April 14, 2020
Q. I am a Chemistry professor who is developing a new tube-based reactor. Stainless steel is too reactive to some of the very sensitive reagents that we are exploring.
I am interested in coating with PTFE the inner surface of stainless steel capillary tubing with dimensions of 1mm ID x 1/16" OD. About 50ft of tubing needs to be coated. If needed the OD can be coated as well. We seek a coating thickness of about 10 microns.
Is it feasible to use a standard PTFE aqueous dispersion such as Chemours Dispersion 30 and slowly pump the dispersion solution through the tubing followed by air drying (by pumping air slowly through the tubing). We can heat the tubing after coating to better fix the coating and could apply in multiple cycles.
Beyond feasibility, I would like to know what dispersion solution is recommended for this application.
- Madison, Wisconsin
December 22, 2020
A. Tubing made from various fluorinated polymers is readily available. Is there a reason why this would not function in your application?
Tom Rochester
CTO - Jackson, Michigan, USA
Plating Systems & Technologies, Inc.
January 1, 2021
In response to the suggestion that we use teflon tubing -- alas, our reactor must operate at temperatures as high as 150 °C and pressures of 50 bar. Thus we need stainless steel (or Titanium, hastelloy, nickel, etc.) that has a teflon-lined inner surface for chemical inertness.
Thank you for your response!
- Madison, Wisconsin
January 2, 2021
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