Argon (Ar) is a noble gas that comprises 0.93 percent of the earth's atmosphere. (Noble gases are a group of rare gases that include argon, helium, krypton, neon, xenon and sometimes radon. They exhibit great stability and extremely low reaction rates. Also called inert gases.)

Colorless, odorless, tasteless and nontoxic, argon forms no known chemical compounds. A specific gravity of 1.38 makes argon 25 percent heavier than air. At atmospheric pressure, it becomes a liquid at -302°F (-186°C). Noncorrosive and non-flammable, argon also exhibits low thermal conductivity and slight solubility in water.

A co-product of oxygen and nitrogen production, argon is manufactured commercially by means of air separation technology. In a cryogenic process, atmospheric air is compressed and cooled. Following liquefaction, the air is fractionally distilled based on the different boiling points of each component. (The boiling point of argon is between those of nitrogen and oxygen.)

During distillation, liquid nitrogen is the first product extracted from the high-pressure column. Next, a stream containing oxygen and argon (plus other gases) is withdrawn. The crude stream, containing approximately 10 percent argon, is refined in a separate distillation column to produce argon with 98 percent purity.

Manufacturers can further refine the stream by mixing the argon with hydrogen, catalytically burning the trace oxygen to water, drying and, finally, distilling the stream to remove remaining hydrogen and nitrogen. Using this process, producers can achieve an argon product with 99.9995 percent purity.

	»	Aluminum To replace air or nitrogen, creating an inert atmosphere conducive to manufacturing aluminum; to assist in the removal of unwanted soluble gases during degasification; and to remove dissolved hydrogen and particulates from molten aluminum.
	»	Electronics To provide a protective atmosphere and heat-transfer medium for growing germanium and silicon crystals for ultra-pure semiconductors.
	»	Glass Because of its low thermal conductivity, argon provides window manufacturers with the gas barrier they need to produce double-pane insulated windows. During the production process, argon gas is injected between two window panes. This insulation barrier greatly improves the window's energy efficiency.
	»	Lighting To fill incandescent and fluorescent light bulbs; to create a blue light in neon-type lamps.
	»	Metal Fabrication To create an inert gas shield during welding; to provide an oxygen- and nitrogen- free environment for annealing and rolling metals and alloys; and to flush molten metals to eliminate porosity in castings.
	»	Steel To displace gas or vapors and prevent oxidation during processing; to obtain temperature consistency and homogenous composition by stirring molten steel; to assist in the removal of unwanted soluble gases during degasification; as a carrier gas, to determine the composition of a sample through gas chromatography; and to flush out carbon monoxide and reduce chromium losses in the Argon-Oxygen Decarburization (AOD) used during stainless steel refining.