Silver - Silver is quite soft and malleable (easily shaped).. With the exception of gold, it is the most malleable and ductile (able to be drawn into very thin wire) of all metals. Silver is harder than gold but softer than copper. It is quite resistant to corrosion and does not oxidize easily. Of all the metals, it is the best conductor of electricity. When silver is plated over copper there can be an accelerated corrosion of the copper at pinholes or breaks in the silver plating. It is then susceptible to the formation of cuprous oxide when stored or used in a moist or high humidity environment. The corrosion is known as "red plague" and is identifiable by the presence of a brown-red powder deposit on the exposed copper. Due to this possible corrosion, it may be wise to consider an insulation over the silver-plated copper wire, such as Teflon. Silver plated copper has applications in the medical field. Silver plating over oxygen-free copper reduces the resistance of the copper, thus enhancing audio and video cables and wires.Gold - Gold is soft and wears easily, so it is often mixed with harder metals. Gold is un-reactive, which means it is resistant to corrosion and tarnishing, at high or low temperatures. Gold is also malleable and ductile. Gold is a very good conductor of electricity and, since it can be drawn into very thin wires, has many applications in electronics. Gold plating on contacts for switches, relays and connectors accounts for most of the gold required each year by the electronics industry. Gold is used in satellites as part of their electronic circuits and as a heat shield. Copper with gold or silver plating can be used in the ultra flexible and ultra miniature wire needed in instrumentation used in the medical industry. Tin - The properties of tin make it ideal for use as a coating. Tin has a low melting point and readily alloys with most other metals, so tin coatings can be easily produced by immersing a suitable prepared metal object in a bath of molten tin. Hot-dipped tin coatings present a good appearance and are tightly adherent. When coated sheets are severely drawn and worked, the coating actually acts as a lubricant. Tin coatings may also be produced by electroplating the metal from an aqueous solution of its salts. Copper tin alloys or tin bronzes are known for their corrosion resistance. Tin bronzes are stronger and more ductile than red and semi-red brasses. They have high wear resistance and low friction coefficient against steel. Tin-nickel is highly resistant to corrosion and tarnish, and is therefore used in electrical equipment and scientific instruments.Copper and nickel may both be used as plating over other metals.Plating for Aluminum:Copper clad aluminum has applications in the medical, electronics, and communications industries, as well as being used in RFI (radio frequency interference) shielding.Plating for Steel:Tin - plated copper clad - This has applications in the electronics and communications industries, and is also used in RFI (radio frequency interference) shielding.Silver - plated copper clad - used in the communications industry.
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