Need New Industrial Seals? Consider Using Phosphor Bronze - An Ancient Alloy With A Modern Twist
If your company is in the market for industrial seals, you might consider ordering some made from phosphor bronze. The following is a brief history of bronze and an outline of the advantages gained by adding phosphorous to this ancient alloy.
The Original Bronze Age Bronze
During the Bronze Age, bronze was the go-to material for tools, weapons, armor, jewelry and decorative items. Originally it was made by combining arsenic with copper to add strength to the soft metal. By the late 3rd millennium BCE, the potentially deadly arsenic was replaced by tin, a reprieve no doubt for those smelters and bronze artists that were continually handling the material.
The Iron Age brought about the popularity of wrought iron, a material that was easier to find. The iron wasn't as strong as the bronze, but it was less expensive. Later, when different cultures started making steel, bronze became a decorative metal. Steel was stronger and could hold a sharper edge longer.
Types of Modern Bronze
Most modern bronze is made of 88 percent copper and 12 percent tin, but there are variations.
- Alpha bronze is a softer version, using only about 4 to 5 percent tin, making it more malleable. Bronze coins are usually made of alpha bronze because it creates a more distinct impression. Other items made from alpha bronze include springs, which by nature must be flexible, turbines and blades.
- Commercial bronze, usually used for statues and other works of art, contains 90 percent copper and 10 percent tin.
- Architectural bronze, a mix of 57 percent copper, 3 percent lead and 40 percent zinc is less malleable, suitable for use in building applications. It's more properly called a brass alloy.
- Bismuth bronze is made of 52 percent copper, 30 percent nickel, 12 percent zinc, 5 percent lead and 1 percent bismuth. Another alloy, this combination of minerals polishes up well and is often used in mirrors and in light reflectors.
- Plastic bronze, a mixture of copper and lead, was invented by the Greeks for ship-building. Together, the two soft metals can be formed into almost any shape, just like plastic.
Industrial-Friendly Properties of Phosphor Bronze
Phosphor bronze is a mixture of copper with between 3.5 percent and 10 percent tin and up to 1 percent phosphorus. The phosphorous is a deoxidizing agent, efficiently removing oxygen from the copper alloy and giving it the following properties.
- The removal of the oxygen makes phosphor bronze resistant to corrosion and oxidation. Regular bronze, as seen on a vintage building, turns green with age.
- Phosphor bronze is especially useful on marine applications because it is resistant to salt water.
- Phosphor bronze is able to withstand high temperatures, friction and heavy wear and tear.
- The alloy is easy to craft into different shapes and can usually be welded.
Using Phosphor Bronze in Seals
The above properties make phosphor bronze the ideal material for seals. While the phosphorous does increase the stiffness of the metal, the material still has enough give to provide a tighter "seal" between one fitting and another. Bronze seals are also used for sleeve bearings, thrust washers and cam followers.
Copper is also an excellent conductor of electricity. This expands the uses of phosphor bronze seals to energy companies. Phosphor bronze alloys are already being used in the production and connection of some solar panel arrays.
In addition to being heat tolerant, bronze seals also perform well under freezing temperatures, making them perfect for use in space and for cryogenic applications. The anti-corrosion factor also makes them ideal for sealing up spent nuclear fuel before disposal. For the latter, sometimes entire canisters are custom made out of phosphor bronze.
For more information about bronze and other metal seals, check out websites like http://www.phoenixspecialty.com/.
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