Monel® is a registered trademark of the International Nickel Company. First developed in 1905, Monel® alloys are nickel-base alloys that contain between 29 and 33% copper. There are 6 types of Monel® depending on the amounts of iron, manganese, carbon, and silicon added. Monel® alloys are stronger than pure nickel, and are resistant to corrosion, although they can become pitted if exposed to salt water. It develops a grey-green patina similar to copper that is chosen for its attractive finish in various applications. They can be fabricated readily by hot and cold working and can also be easily welded, soldered, and brazed. Up to the 1940s Monel® was one of the most popular metals on the market, only replaced by Stainless Steel in the 1950s. Monel® is available in different forms including sheets, plates, rods, bars, and tubes. The presence of Monel® can lead to galvanic corrosion. In other words, if aluminium, zinc, or iron are used as fasteners for Monel® and then exposed to certain conditions, the metal fasteners will quickly corrode.