Non stick metal coating comes with unique properties
Non stick is a property needed in many applications from moulds and other fasteners to pots and pans. A non stick coating for metal is usually a fluoropolymer compound which provides the substrate with the following properties:
- Low coefficient of friction: range of 0.05 to 0.20
- Temperature resistance: from 370 °C to -270 °C
- Chemical resistance: to all chemicals except molten alkali metals and reactive fluorinating agents
- High dielectric strength, low dissipation factor and high surface resistivity
Non stick coating is also known as release coating due to its anti stick properties. Non stick metal coatings are suitable for guaranteeing sufficient lubrication in machine parts; but it is also applied on consumer goods such as sauce pans.
The 3 types of non stick coating
1. Fluoropolymer coatings – the most durable non stick effect
The most common types of non stick coatings for metal surfaces are fluoropolymers. Many of the different compounds have been registered and are now better known by the tradenames. Example of such are Teflon, Xylan and Greblon.
- PTFE (polytetrafluoroethylene) coating: the world’s most popular non stick coating for metal, also the one with the most resistance to high temperatures (370 °C)
- FEP (fluorinated ethylene propylene) coating: similar to PTFE, but has lower melting point
Suitable uses: consumer goods (eg. cookware) and industrial applications such as machine parts.
2. Silicone coatings – non toxic and inexpensive
Silicone coatings are a more environmentally friendly option than fluoropolymers. Unfortunately, they are not nearly as durable as fluoropolymers. However, the silicone coatings are clearly the cheapest option to create a non stick surface. Therefore, they are used in applications that do not require a long life expectancy.
Suitable uses: bakeware and low end cookware
3. Ceramic coatings – for cookware
Ceramic coatings have already been long in the market.However, their use as a non stick coating is a rather new thing. Especially in the are of cookware. Ceramic non stick coatings are more durable than silicone coatings but also non toxic.
Suitable uses: bakeware and cookware, industrial applications.
Choose the best non stick metal coating
Due to the fact that each of the different types of non stick coatings have unique characteristics, the application defines the best coating. For example, when the environment involves high temperature, PTFE coating is the most suitable. On the other hand, when a cheaper option is sought and long term durability not required, a silicone coating is more suitable.
In general, when applying non stick coatings, it is important that the substrate is prepared appropriately. This includes roughening the surface to guarantee good adhesion. Sometimes the performance of non stick metal coatings can be improved by plasma coating an additional layer of metal, which the anti stick coating is applied on.
Top 3 myths about non stick coating
- All nonstick coatings are the same
Nope, each composition of non stick coating has its own unique properties. A PTFE coating is not an FEP coating.
- Non stick coating for metal are not durable
It used to be true in the 70’s but not anymore. Some non stick coatings are guaranteed a life long warranty when applied on metal surfaces. However, keep in mind that for example silicone coatings lose their non stick properties sooner than fluoropolymers.
- Non stick coating contains PFOA
Not anymore. Perfluorooctanoid acid (PFOA) is carcinogenic, and was used PTFE coatings. However, nowadays it is very rare in coatings: even if it were used, it would be destroyed during baking the coating.