Aluminium foil Aluminium foil Aluminium foil (or aluminum foil), often referred to with the misnomer tin foil, is aluminium prepared in thin metal leaves with a thickness less than ; thinner gauges down to are also commonly used. In the United States, foils are commonly gauged in thousandths of an inch or mils. Standard household foil is typically thick, and heavy duty household foil is typically . The foil is pliable, and can be readily bent or wrapped around objects. Thin foils are fragile and are sometimes laminated to other materials such as plastics or paper to make them more useful. Aluminium
Foil bearing Foil bearing Foil bearings, also known as foil-air bearings, are a type of air bearing. A shaft is supported by a compliant, spring-loaded foil journal lining. Once the shaft is spinning fast enough, the working fluid (usually air) pushes the foil away from the shaft so that no contact occurs. The shaft and foil are separated by the air's high pressure, which is generated by the rotation that pulls gas into the bearing via viscosity effects. A high speed of the shaft with respect to the foil is required to initiate the air gap, and once this has been achieved,