Atomic Number	82
Atomic Weight	207.2
Melting Point	600.61 K (327.46°C or 621.43°F)
Boiling Point	2022 K (1749°C or 3180°F)
Density	11.342 grams per cubic centimeter
Phase at Room Temperature	Solid

Lead alloy has been known since ancient times. It is sometimes found free in nature, but is usually obtained from the ores galena (PbS), anglesite (PbSO4), cerussite (PbCO3) and minum (Pb3O4). Although lead makes up only about 0.0013% of the earth's crust, it is not considered to be a rare element since it is easily mined and refined. Most lead is obtained by roasting galena in hot air, although nearly one third of the lead used in the United States is obtained through recycling efforts.

Lead is a soft, malleable and corrosion resistant material. The ancient Romans used lead to make water pipes, some of which are still in use today. Unfortunately for the ancient Romans, lead is a cumulative poison and the decline of the Roman empire has been blamed, in part, on lead in the water supply. Lead is used to line tanks that store corrosive liquids, such as sulfuric acid (H2SO4). Lead's high density makes it useful as a shield against X-ray and gamma-ray radiation and is used in X-ray machines and nuclear reactors. Lead is also used as a covering on some wires and cables to protect them from corrosion, as a material to absorb vibrations and sounds and in the manufacture of ammunition. Most of the lead used today is used in the production on lead-acid storage batteries, such as the batteries found in automobiles.


Lead Use by End Consumption

Several lead alloy are widely used. Solder, an alloy that is nearly half lead and half tin, is a material with a relatively low melting point that is used to join electrical components, pipes and other metallic items. Type metal, an alloy of lead, tin and antimony, is a material used to make the type used in printing presses and plates. Babbit metal, another lead alloy, is used to reduce friction in bearings.

Lead forms many useful compounds. Lead monoxide (PbO), also known as litharge, is a yellow solid that is used to make some types of glass, such as lead crystal and flint glass, in the vulcanizing of rubber and as a paint pigment. Lead dioxide (PbO2) is a brown material that is used in lead-acid storage batteries. Trilead tetraoxide (Pb3O4), also known as red lead, is used to make a reddish-brown paint that prevents rust on outdoor steel structures. Lead arsenate (Pb3(AsO4)2) has been used as an insecticide although other, less harmful, substances have now largely replaced it.

Lead carbonate (PbCO3), also known as cerussite, is a white, poisonous substance that was once widely used as a pigment for white paint. Use of lead carbonate in paints has largely been stopped in favor of titanium oxide (TiO2). Lead sulfate (PbSO4), also known as anglesite, is used in a paint pigment known as sublimed white lead. Lead chromate (PbCrO4), also known as crocoite, is used to produce chrome yellow paint. Lead nitrate (Pb(NO3)2) is used to make fireworks and other pyrotechnics. Lead silicate (PbSiO3) is used to make some types of glass and in the production of rubber and paints.

Because Lead is very soft and ductile, it is normally used commercially as Lead Alloys. Antimony, tin, arsenic, and calcium are the most common alloying elements. Antimony generally is used to give greater hardness and strength, as in storage battery grids, sheet, pipe, and castings. Antimony contents of Lead-antimony alloys can range from 0.5 to 25%, but they are usually 2 to 5%.

Lead-Calcium Alloys have replaced Lead-antimony alloys in a number of applications, in particular, storage battery grids and casting applications. These alloys contain 0.03 to 0.15% Ca. More recently, aluminum has been added to calcium-Lead and calcium-tin-Lead alloys as a stabilizer for calcium. Adding tin to Lead or Lead alloys increases hardness and strength, but Lead-tin alloys are more commonly used for their good melting, casting, and wetting properties, as in type metals and solders. Tin gives the alloy the ability to wet and bond with metals such as steel and copper; unalloyed Lead has poor wetting characteristics. Tin combined with Lead and bismuth or cadmium forms the principal ingredient of many low-melting alloys.

Arsenical Lead (UNS L50310) is used for cable sheathing. Arsenic is often used to harden Lead-antimony alloys and is essential to the production of round dropped shot.

Lead-base bearing alloys, which are called Lead-base babbitt metals, vary widely in composition but can be categorized into two groups:

• Alloys of Lead, tin, antimony, and, in many instances, arsenic
• Alloys of Lead, calcium, tin, and one or more of the alkaline earth metals

Ammunition: Large quantities of Lead alloy are used in ammunition for both military and sporting purposes. Alloys used for shot contain up to 8% Sb and 2% As; those used for bullet cores contain up to 2% Sb.

Terne Coatings: Long terne steel sheet is carbon steel sheet that has been continuously coated by various hot dip processes with terne metal (Lead with 3 to 15% Sn). Its excellent solder ability and special corrosion resistance make the product well-suited for this application.

Lead Foil, generally known as composition metal foil, is usually made by rolling a sandwich of Lead between two sheets of tin, producing a tight union of the metals.

Fusible Alloys: Lead alloyed with tin, bismuth, cadmium, indium, or other elements, either alone or in combination, forms alloys with particularly low melting points. Some of these alloys, which melt at temperatures even lower than the boiling point of water, are referred to as fusible alloys.

Anodes made of Lead Alloys are used in the electro winning and plating of metals such as manganese, copper, nickel, and zinc. Rolled Lead-calcium-tin and Lead-silver alloys are the preferred anode materials in these applications, because of their high resistance to corrosion in the sulphuric acid used in electrolytic solutions. Lead anodes also have high resistance to corrosion by seawater, making them economical to use in systems for the cathodic protection of ships and offshore rigs.