Alloy are relatively similar in size, the atom exchange method usually happens, where some of the atoms composing the metallic crystals are substituted with atoms of the other constituent. This is called a "substitutional alloy". Examples of substitutional alloys include bronze and brass, in which some of the copper atoms are substituted with either tin or zinc atoms respectively. In the case of the interstitial mechanism, one atom is usually much smaller than the other and can not successfully substitute for the other type of atom in the crystals of the base metal. Instead, the smaller atoms become trapped in the
Antimicrobial copper-alloy touch surfaces hospital-borne pathogens such as "S. aureus," "P. aeruginosa" and "A.baumanii". In a 30-week clinical trial at the Hospital del Cobre ("Copper Hospital"), extensive microbial analyses were implemented at the facility's intensive care unit (ICU). Nine hundred ninety copper surfaces from 90 rooms containing 6 different copper objects were studied against an equivalent number of rooms and surfaces containing non-copper objects. Over-the-bed tables were made from copper alloy C70600. Bedrails were clad with copper alloy C11000 foils. Visitor chairs were fitted with copper alloy C70600 armrests. Copper alloy C71000 intravenous poles were provided. Writing pens used to input data on a