Because of its impurities, common zinc is easily attached by dilute acids, with generation of hydrogen and zinc salt. It precipitates more noble metals such as copper, lead, silver, etc.., from their saline solutions.
Zinc salts are colourless or white. Their solutions give a white hydroxide precipitate with alkali, soluble in an excess of reagent.
Applications. Because of its durability when exposed to air, zinc is used in plates or sheets for roofing; zinc plates or sheets are also used in the graphic arts and in dry batteries. As molten cast, it is used to manufacture various objects, which are then coated by electroplating with a special alloy that gives them the appearance of art bronzes. Zinc has an effective protective action on iron and steel exposed to certain environments, such as water, water vapour, organic compounds, benzene, or chlorinated solvents. Such protection is achieved by several processes.
Zinc alloys (zama)
Zinc is part of several copper alloys, brass, special bronze, maillechort. Zinc is the main constituent of Zama alloys, whose name is derived from Zinc, Aluminium, Magnesium. It is a group of alloys with a high zinc content, which must be 99.99% pure, as well as with variable proportions of aluminium, copper, and magnesium. They are used, after casting, for taps, door handles, pump bodies, and carburettors.
Galvanica Consonni Srl makes Zama chromium plating.