Rare metal in the clank iron bone
Rare elements are the natural elements of reserves, sparsely distributed and human less commonly used, often used to create special metal materials, in the aircraft, rockets, atomic energy and other industrial areas is a key material.
In the rare metal family, there are many stubborn "tough guy." They seem to have clank iron, not only high melting point, but also a very strong anti-corrosion ability. Even exposed to the air, it is not easy to be oxidized.