Bauxite is most commonly found in sub-tropical places like Africa, the West Indies, South America, and Australia — although there are some small deposits in other places like Europe. This bauxite is then processed into aluminum oxide, which just consists of atoms of aluminum and oxygen bonded together.
The aluminum oxide then has an electrical current run through it, which separates the different components from each other. Oxygen bubbles form at one end, and pure molten aluminum droplets collect at the other end. About tons of bauxite is processed into 2 tons of aluminum oxide, which creates 1 ton of pure aluminum. Aluminum corrodes much more slowly than other metals like iron. Normally, when water comes into contact with metal it encourages the metal to give up its electrons even faster to the oxygen around it.
Aluminum has a special reaction to water though. When water touches aluminum, the aluminum and the oxygen atoms contained in the metal — not the oxygen in the air surrounding it move further apart from each other. Rust is a naturally occurring chemical reaction. There are many ways you can prevent your metals from rusting, such as metal paints and coatings , sacrificial barriers, barrier films as well as numerous anti-rust solutions and tin plating. Each method utilizes different compounds and materials to create a protective barrier between the metal and the elements that cause rust and corrosion.
Our trained staff can help you choose the best metal for your next project. Contact us today for all of your steel needs. What is Rust? What is Corrosion? What is Reduction? In general, corrosion is the deterioration of a metal by oxidation or other chemical action. Rust is a term used to describe the actual corrosion of iron and iron alloys. However, like all metals, Aluminum is susceptible to corrosion. But the fact is that pure aluminum reacts so readily with water that, according to the laws of chemistry, the aluminum shell of an airplane should actually dissolve in the rain.
Brass does not rust for the same reason as aluminum. It has a negligible amount of iron in it. Therefore, no iron oxide, or rust, can form. However, copper can form a blue-green patina on its surface when exposed to oxygen over time. Bronze does not rust for the same reason as aluminum. It has a negligible amount of iron.
Copper does not rust; however, it can corrode. Copper is naturally brown and turns a shade of bright green as it corrodes. The alloys form a protective rust patina which reduces the corrosion rate with time. Galvanizing is a method of rust prevention. This is accomplished through hot-dip galvanizing or electroplating. The iron or steel object is coated in a thin layer of zinc.
This stops oxygen and water reaching the metal underneath but the zinc also acts as a sacrificial metal. Zinc is more reactive than iron, so it oxidizes in preference to the iron object.
This is due to its light weight, but also to its resistance to corrosion. When the alloy is exposed to water, a film of aluminum oxide forms quickly on the surface. The hard oxide layer is quite resistant to further corrosion and protects the underlying metal. These three metals contain little or no iron, and so do not rust, but they can react with oxygen.
Copper oxidizes over time to form a green patina, which actually protects the metal from further corrosion. Bronze is a mixture of copper and tin, along with small amounts of other elements, and is naturally much more resistant to corrosion than copper.
Brass is an alloy of copper, zinc, and other elements, which also resists corrosion. Galvanized steel takes a long time to rust, but it will eventually rust. This type is carbon steel that has been galvanized, or coated, with a thin layer of zinc. The zinc acts as a barrier preventing oxygen and water from reaching the steel, so that it is corrosion protected.
Even if the zinc coating is scratched off, it continues to protect nearby areas of the underlying steel through cathodic protection, as well as by forming a protective coating of zinc oxide. Like aluminum , zinc is highly reactive to oxygen in the presence of moisture, and the coating prevents the iron in the steel from further oxidation.
0コメント