Fluorine-based coatings 2017-11-28T09:25:33+00:00

Fluorine-based coatings

The surface treatment of a part consists in reinforcing and protecting it to enhance its basic properties and its adaptation to a certain environment. When we wish to reduce rubbing between parts in contact, it makes sense to first turn towards materials that have the lowest friction coefficient : fluororesins.

Properties :

Fluororesins display a combination of outstanding properties :

  • High temperature resistance

  • Anti-adhesion

  • Friction resistance

  • Resistance to severe abrasion due to chemical attacks

  • Tenue à la corrosion ambiante

  • Fretting corrosion

  • Tenue à la charge

  • Excellentes isolations électriques

  • Parfaite stabilité dimensionnelle pour des épaisseurs inférieures à 50 µ

Coatings :

PTFE, FEP, PFA, PEEK / Revêtement ECTFE HALAR, Fluorimid®, Fluoref®, Deltaflon®, Microflon®

Fluorotechnique has an extensive range of products to solve adhesion, clogging, friction, chemical resistance and food contact problems :

XYLAN, TEFLON

PTFE (polytetrafluoroethylene), which is better known under the brand name Teflon®, is often used as a reference for antiadhesives.

Friction :

Fluorimid®, Fluoref® and Microflon® processes associate fluororesins with fillers aimed at reinforcing the basic resins. They allow metal/metal frictions without galling, without wear and with considerable friction coefficient decrease (down to 0.02).

Anti-adhesion :

The surface tension of fluororesins prevents all adhesion from: glues, food products, limescale, frost, rubber, epoxy, polyester, diverse melted thermoplastics, thermosettings, fertilizers, etc.

Implementation :

In general, these coatings require operating temperatures between 120 and 400°C. Depending on the substrates and methods, we can obtain diffusions in the metal substrates implying penetrations that can reach 5 to 20 µ.

Fluorotechnique developed original processes ensuring perfect adhesion to metal and high thickness uniformity. Depending on the technical problems, it is possible to reinforce thin layers in order to optimize a particular property, namely :

  • Obtaining strict tolerances on series parts

  • Wear resistance

  • Fretting – corrosion

  • Thermal resistance, etc..

  • Conductivity

In order to answer problems such as dry lubrication or extrusion moulding, our fluoropolymer coatings may be reinforced with resistant and hard layers : for example, the EXCALIBUR metal deposit.

Characteristics

Nature : PTFE, PFA, FEP, ETFE – Thickness : from 2 µm to a few millimeters
• Processing temperature : About 350 °C –Operating temperature: -220°C to +260°C

Available technical solutions


Food, stationery, moulds, automotive tools, inks, paints, glues.

Fluoropolymer coatings (Teflon®) are well-known, especially in household products, and their anti-adhesive property is greatly appreciated. Industrial processes have allowed a significant improvement in their performances, and led to their use many industrial cases as part of our range of products Microflon®, Fluoref®, Fluorimid®.

The surface tension of fluororesins (FEP, PFA, MFA, PTFE) prevents all adhesion from: glues, food products, limescale, frost, rubber, epoxy, polyester, diverse melted thermoplastics, thermosettings, fertilizers, cements…

Depending on the case, the chosen coatings have characteristics that can be modified depending on whether we simultaneously encounter bonding & corrosion, bonding & wear, bonding & high temperature. Our experience allows us to make the best choice among possible variations.

Here are some cases of anti-adhesion :

  • No bonding of elastomer seals with limescale
  • Anti-adhesion on moulds for plastic materials that allows easy de-moulding, prevents distortion of the parts, and increases production capacity
  • No clogging of sticky powdered products for parts used in the food sector
  • Non-adhesion on tools on which liquid paint or powder settles, eventually forming a thick, hard-to-clean crust. Works as a replacement for thermal and chemical stripping on tool parts, in all industries using paints or glues
  • Food-grade coatings, FDA & European standards

 

Cookie-cutter                Multiple moulds                Hopper

Aéronautics, packaging

As thin coatings, fluoropolymers can resist temperatures from -180°C to 280°C. They can reach a 350°C peak ; PTFE fluororesins have a degradation rate in the range of 0.0006% an hour, in terms of weight. However, at such temperatures, their mechanical resistance is obviously weak.

We treat other types of coatings (especially MOS² based ones) that have a much higher temperature resistance (in the range of 450°C continuously).

For any other temperature above 450°C, do not hesitate to contact us. We are able to provide you with different coating solutions.

Nuclear valve

Resistance to salt fog up to 900 hours

Corrosion problems of metallic parts can be generally divided into 3 groups.

Resistance to very aggressive chemical agents (bases or acids) at high temperatures (150°C). It is almost essential to consider using thick coatings like ECTFE, ETFE or PFA.

Migration of thin molecules through any polymer becomes negligible for thicknesses over 600µ and up to 1000µ depending on the resins. These resins are applied using electrostatic powder coating on hot parts, and thicknesses  from 600µ to 1mm can be applied. They are designed especially for the production of anti-corrosive coatings in the chemistry sector : containers, stirrers. Furthermore, we are able to bring you solutions in terms of cold polymerizable coatings for parts requiring repair.

Resistance to environmental corrosion which is unanimously quantified by the number of hours of resistance to salt fog.

It is rare that we use polymers alone to solve an oxidation problem. We ask for other performances in the same time, such as a low friction coefficient, noice-cancelling function, temperature resistance, electrical friction or insulation. Many solutions combined with our fluororesin solutions can be provided: zinc flake, nickel plating, hard anodizing, phosphating…

Resistance to fretting corrosion and galvanic couple.

Mechanical parts in a relative movement of low amplitude but high frequency sometimes show signs of significant corrosion and wear. Our Fluoref®, Fluorimid® or Microflon® coatings offer high-performance solutions, the thin deposits penetrating the part behave as dry lubricants welded to the metal. A comprehensive study on the choice of materials in contact must be made in each case.

 Chemistry valve                                                                  Offshore project           

Scratch resistance : stationery, industrial tooling

Just like any coating, fluororesins wear too.

That is why we are able to find compromises in our coatings, by conserving the initial properties we desire (anti adhesion, temperature resistance) and by granting them others, either by fillers associated to our fluororesins, either by preparation of adequate surfaces (hard underlays), or by different thicknesses that allow us to significantly increase the lifespan of our coatings.

Some typical examples : paper industry, industrial equipment, moulders…

  

Clamp Technip      Textile/composite industry roll

High-accuracy adjustment of mechanical parts : aeronautics, armaments, nuclear

Fretting corrosion concerns damage caused by corrosion at the level of contact between two metallic surfaces in a relative movement with each other. This phenomenon can be emphasized  by a galvanic couple depending on the setting, when the compared metals are of different material.

It especially happens when the interface is subjected to vibrations (repeated relative movement of two touching surfaces) and to compressive loads. This relative movement can be very small (small oscillation around some µ). In the presence of a continuous friction movement in a corrosive environment, we will preferably use the word « tribocorrosion ».

Our means to reduce this corrosion are the use of auto-lubricating coatings ; the friction is thus limited and oxygen is excluded from the surface. Our PTFE-based treatments or others (FEP ; Mos²) are used in the sector of fine mechanics. For some sectors (aeronautics, armaments, space, nuclear…), we are capable of coating pieces in very strict tolerances (3µ+/-1µ) for which a 100% dimensional control can be executed before and after treatment (Microflon® range).

        

Kerosene regulation bushel   Air compressor piston   Helicopter engine gear ring

Up to friction coefficients <0.02: aeronautics, automotive supply industry

It is also possible to benefit from the excellent friction properties of fluororesins on rubbing mechanical parts. Many types of fluororesins display qualities and have other characteristics, not as well-known as the ones previously mentioned :

  • Excellent adhesion on metal, light alloys, ceramics, cast iron
  • Coating accuracy: we have the possibility to handle extremely strict tolerances for fine mechanics. Thicknesses of 3µ +/-1µ can be reached. For thicker treatments, we can for example obtain 10µ +/-3µ. It is even possible to adjust treated materials with a zero clearance fitting (bushel of a cylindrical valve for aeronautics industry).
  • Under heavy loads, the friction coefficient can reach 0.02. Many applications result from the low static friction coefficient: bonding problems, either metal-metal, or rubber-metal in aeronautics and hydraulics are solved.

Fluorimid®, Fluoref® and Microflon® processes associate fluororesins with fillers aimed at reinforcing the basic resins. They allow metal/metal frictions without galling, without wear and with considerable friction coefficient decrease (down to 0.02). Any mechanical bonding effect is eliminated. Elastomers do not stick on a coated part. The stick slip effect is suppressed.

We generally treat only one part out of two : preferably the male part. The counterpart must have the best possible quality as to its roughness, hardness and geometry. Thermal stabilizations of the parts to be treated have to be considered if geometrical deformations are likely to occur.

      

Pistons

Electrical Insulation

PTFE is a great insulator and possesses outstanding dielectric properties. It is also resistant to Corona discharge and electric arcs.

However, filled PTFE can be electrically conductive :

As a matter of fact, Fluorotechnique can help customers enchance the properties of PTFE by making a powder mixture in order to maintain the electrical flow of the coated part.

High insulating properties combined with heat and aging resistance make polymer coatings a first choice material for electrical and electronics industries (cable sleeving, insulators…)

Noise-cancelling function

Noise and vibrations can be quite invasive in different industries or even in daily life. Some coatings are made to reduce the noise caused by friction or metal on metal rubbing. These solutions prevent using lubricant, which avoids all risk of noise nuisance and reduces maintenance intervals.

 

Water savings

Our diverse coatings can be used in the sector of drinking water distribution systems, and allows substantial savings. Indeed, processed parts can be easily and quickly cleaned, with less water.