How does vacuum coating produce thin metallic surface layers?

Vacuum coating is a physical process used to create thin, bright, and attractive metallic layers on a surface by evaporating and depositing a coating metal within a high-vacuum environment.1

In the context of physical deposition methods, this process typically involves two primary techniques:

• Evaporation Deposition: A metal source is heated inside a vacuum chamber—often using an electron beam or by passing an electric current through a container. The metal turns into a vapor, which then travels and condenses onto the cooler surface of the substrate to form a thin film.2
• Sputtering: A metal source and the substrate are placed in a vacuum chamber with an inert gas like argon. An electric field ionizes the gas, accelerating ions toward the metal source. The impact of these high-energy ions knocks metal atoms loose, creating a vapor that condenses on the substrate to form the desired layer.2

Unlike chemical methods, these physical processes are often performed at lower temperatures, reducing the risk of thermal damage to the substrate.2