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Date: 2015-10-07; view: 604.

C. Compounds

B. Alloys

The most widely used alloy of zinc is brass, in which copper is alloyed with anywhere from 9% to 45% zinc, depending upon the type of brass, along with much smaller amounts of lead and tin. Alloys of 85–88% zinc, 4–10% copper, and 2–8% aluminum find limited use in certain types of machine bearings. Alloys of primarily zinc with small amounts of copper, aluminum, and magnesium are useful in die-casting. Similar alloys with the addition of a small amount of lead can be cold-rolled into sheets. An alloy of 96% zinc and 4% aluminum is used to make stamping dies for low production run applications where ferrous metal dies would be too expensive.

Zinc oxide is perhaps the best known and most widely used zinc compound, as it makes a good base for white pigments in paint. It also finds industrial use in the rubber industry, and is sold as opaque sunscreen. A variety of other zinc compounds find use industrially, such as zinc chloride (in deodorants), zinc sulfide (in luminescent paints), and zinc methyl or zinc diethyl in the organic laboratory. Roughly one quarter of all zinc output is consumed in the form of zinc compounds.

Uranium is a chemical element in the periodic table that has the symbol U and atomic number 92. Heavy, silvery metallic, naturally radioactive, uranium belongs to the actinide series. Its isotopes ²³⁵U and to a lesser degree ²³³U are used as the fuel for nuclear reactors and the explosive material for nuclear weapons. Depleted uranium (²³⁸U) is used in kinetic energy penetrators and armor plating.