Coatings are primarily used to protect the surface of a material and as a decorative layer. Decorative coatings are predominantly paints that are protective in nature and are specially formulated for a specific use. Coatings date back to the early 19th century where linseed oil and limestone were used.

In outdoor applications, a primer coating is applied first, to seal and protect a surface. These primers have matte finishes that create a base coat for the decorative topcoat to adhere to. Primers are used to cover and seal concrete, wrought iron and wood. Topcoats that are designed for outdoor use are fade-resistant, waterproof and can withstand varying temperatures and humidity.

Protective coatings are also designed for specific purposes and are used in industrial processes for mass production. Most construction materials are built to last and need to be coated to protect them from nature’s elements. Metal, concrete, and even glass, all have protective coatings. Coating industrial machines helps improve their performance and in resisting wear and tear. Industrial cutting, polishing and grinding tools are coated with carbides. Anti-skid coatings are also applied to floors and bathroom tiles. Seawater is corrosive in nature, therefore, ships need to be coated and painted to withstand harsh outdoor conditions over a long period of time. Medical equipment is also coated with transparent sealants having anti-microbial properties, essential to hospital environments.

The process and materials used for coating flexible materials are far more complex than primers and paints. New bonding techniques have been developed to coat graphite frames of lightweight aircraft parts. One example of this is that newer turbofan jets have titanium coated graphite engine blades. Process of bonding titanium to graphite requires variable temperature application techniques which are still being perfected.

There are entire industries dedicated to the formulation and application of coatings. They are essential to the maintenance of our modern industrial society.