Tools, zinc plating

Zinc plating Tools made of steel are often covered with a layer of zinc to prevent corrosion. Zinc is more reactive than the lead in steel. During zinc plating, the zinc replaces some of the surface lead, coating the steel. 

The zinc-base dic-casting alloys are the mast widely used. A typical composition is 1.0% copper. 3.9% aluminum, 0.06% magnesium, balance zinc. This alloy has a strength of about 43.000 psi (3.061 atmospheres) with 3% elongaliun in 2 inches (3 centimeters). Typical applications are carburetors, fuel pumps, tools, typewriter frames, instrument cases, and hardware often finished by chromium plating. 

Two special copper alloys, beryllium copper and nickel silver, although only used on a small scale, contribute valuable metal properties for special uses. Two percent beryllium added to copper gives greater fatigue resistance to the metal and confers a nonsparking (on impact) quality to tools made of this alloy, important for impact tools in flammable or explosive atmospheres. Nickel silver, a copper/nickel/zinc alloy with an appearance very like silver, is important as the strong base metal for silver-plated tableware. 

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