Clad

Clad is a term used as an adjective and as the past participle of the verb to clad, meaning to cover or overlay with a layer of material. When an object is described as clad, its surface has been wrapped, coated, or bonded with another substance for protection, durability, or appearance.

In materials science and engineering, cladding refers to a layered structure in which a core substrate is joined to a distinct outer layer. The cladding layer provides properties not present in the core, such as corrosion resistance, wear resistance, improved electrical or thermal behavior, or aesthetic effects. Common examples include copper-clad steel and nickel-clad steel; aluminum or copper cladding on steels, and copper-clad aluminum used in conductors.

In construction, cladding is exterior or facade material applied to a building frame. It protects the structure from weather and contributes to its look. Materials include metal panels, brick, stone, wood, vinyl, and composite panels, typically fixed to a subframe and designed for durability and energy performance.

In optics and electronics, cladding denotes a surrounding layer with different properties from the core, most commonly a material with lower refractive index around an optical fiber core to confine light. The term also appears in electrical cables and printed circuit boards as a protective outer layer or outer conductor.

Cladding offers a way to combine properties of two materials but can pose challenges such as delamination or differential thermal expansion. Etymology traces to the verb clad, meaning to cover.