Iron, Physical and Chemical Properties

Iron is an ancient metal that became the basis of our civilization. It is usually used in the form of steel which contains 0.5% and 1% carbon. World steel production in 1 year equals the production of all other metals combined in 10 years. It is a transition metal, that is, it is less reactive than the typical metals but more reactive than the less-typical metals. It occurs as an alloy with nickel in meteorites.

Physical Properties

Iron exists in several allotropic forms:

• α-Iron: Magnetic and stable to 768°C, crystallizes in a body-centered cubic. It dissolves very little carbon (0.025% at 721°C).

• β-Iron: It is a form stable between 768°C and 910°C. It is alpha iron that has lost its magnetism. It does not dissolve carbon.

• γ-Iron: This form is stable between 910°C and 1,390°C, crystallizes in face-centered cubic. It is nonmagnetic and dissolves 2% carbon at 1,102°C. Carbon in solution forms a hard carbide.

• δ-Iron: It is nonmagnetic and stable between 1,391°C and the melting point...