Bimetallisk

Bimetallisk, or bimetallic in English, describes materials or systems composed of two distinct metals. In metallurgy, bimetallic structures exploit the complementary properties of two metals—such as hardness, strength, wear resistance, or corrosion resistance—by bonding them into a single component.

Common forms include laminated plates, rings, or coins with a central layer of one metal and an outer layer of another. Production methods include cladding (hot or cold rolling to fuse layers), diffusion bonding (high temperature and pressure), explosion welding, and roll bonding. The quality of the bond and the compatibility of thermal expansion are important considerations.

Applications include coinage (many countries produce bimetallic coins with a core of one metal and an outer ring of another, used to deter counterfeiting and extend life), electrical contacts, corrosion-resistant piping and fittings, wear-resistant bearings, and jewelry.

Economics: Bimetallism is a historical monetary system in which a country's standard unit is defined in terms of both gold and silver at a fixed ratio. It competed with monometallic gold or silver standards and largely disappeared in the 20th century with the move to fiat money or gold standard regimes.

Etymology: from Latin bi- meaning two + metallum meaning metal.