Define substrate


Substrates can be divided into two groups when applying powder coatings: degassing substrates and non-degassing substrates.
When curing, the substrates that are prone to degassing can cause defects on the surface. For these substrates, you will need to use the adapted primer/powder.

The information below is a compact overview of the most used substrates. We strongly advise to discuss this with your job coater to ensure the correct substrate for your project. 

Degassing substrates

Cast Iron

Cast iron is a group of iron-carbon alloys containing a higher proportion of carbon than steel.

Properties:

  • Good resistance to abrasion and indentation
  • High tensile strength (resistance to breaking when under tension)
  • Prone to rusting
  • Heavy
  • Maintenance is easy
  • Common uses include structural components

Hot dip galvanised steel

Hot-dip galvanising (HDG) is the process of dipping fabricated steel into a big bath containing molten zinc. The zinc acts as a barrier preventing oxygen and water from reaching the steel, so that it is protected from corrosion. It provides a chemical protection.

The key difference between galvanisation and hot-dip galvanisation is that most galvanised materials have a smooth and sharp finish, whereas hot-dip galvanised structures have a rough finish.

Properties:

  • High life expectancy
  • Very good corrosion resistance
  • Rather complex technological process
  • Used to protect steel embedded in soil and/or concrete or submerged in water

Zn or ZnAl metallised steel

Metallising is a zinc-based or zinc-aluminium based spray-on protection option for structural steel. It provides a mechanically bonded protection.

Properties:

  • The spray coating provides a strong barrier between the environment and the steel surface
  • Reduced oxidation
  • Very good corrosion resistance
  • Slip resistance
  • Common uses include big, structural steel projects that are subjected to harsh environments (e.g. bridges)

Non-degassing substrates

Aluminium

Aluminium is a silvery-white, lightweight metal. The shape of aluminium parts is created by extrusion or plate cut.

Properties:

  • Strong, yet lightweight compared to other metals
  • Can be more easily dented and scratched than steel
  • Ductile and malleable metal
  • Common uses for aluminium include roofs, siding, translucent panes, window and doorframes, staircases, air conditioning systems, solar protection, heating systems, furniture and many other things

Mild steel

This is steel which contains only a small percentage of carbon and is strong and easily worked but not readily tempered or hardened.

Properties:

  • Does not have the chromium oxide protective layer and so the iron present reacts more with the moisture in the air to produce iron oxide or 'rust'
  • Good ductility and weldability
  • Mild steel is often used as a building frame material thanks to its incredibly high strength
  • Common uses for mild steel include automobile body parts, plates and wire products

Black steel

Black steel is made of steel that has not been galvanised. Its name comes from the scaly, dark-coloured iron oxide coating on its surface.

Properties:

  • Superior rust and corrosion resistance
  • Common uses for black steel include transport of natural and propane gas in residential applications

Magnelis®

Magnelis® is a metallic, steel-coated product that uses a metallic chemical composition of zinc with 3.5% aluminium and 3% magnesium and is applied in a hot-dip process.

Properties:

  • High corrosion resistance, particularly where there is exposure to ammonia and chloride
  • Able to withstand some of the harshest environments
  • Improved corrosion behaviour on cut edges
  • Lends itself to folding, bending and forming
  • Common uses for Magnelis® include buildings by the seaside, outdoor civil construction and industrial installations

Sendzimir

The Sendzimir process is a surface coating process where the workpiece is dipped into a bath of zinc and aluminium to form a surface. This process is used to galvanise a steel strip by using a small amount of aluminium in the zinc bath and producing a coating with essentially no iron-zinc alloy.

The coating produced using this method is somewhat more ductile than that created by conventional hot-dip galvanising because of the addition of aluminium.

Properties:

  • Guarantees high resistance and durability characteristics

Zinc electroplating

Electroplating uses the process of electrodeposition. The metal is dipped in a chemical bath containing dissolved zinc. When a direct current is applied, the zinc metal at the anode begins to dissolve, and the free metal ions reach the cathode to form a thin layer of coating on the metal. It is a process whereby zinc is applied by using an electric current.

Properties:

  • Protects metals from corrosion effects
  • Often used to improve the appearance of the surface of a metal which, in turn, makes the material become more attractive
  • Can be made in an enormous range of textures and structures