Powder coating is the most popular process in finishing non highly polished metal. There are two options for powder coating:
Thermoset – the most common of the two processes uses powder polymer that, when baked in a coating oven, makes the powder react with other chemical groups, increases the molecular weight and improves the surfaces performance properties.
Thermoplastic – most commonly used for external environments where coating thicknesses of 30 mils is desirable. Typical of this would be a coastal location where salt spray protection is required and/or life expectancy of 10 years plus of exposure to UV light.