Alloying Metal

  • Metals are sometimes used in their pure form; however more often than not, they are alloyed with other metals (or carbon) to give the metal more desirable properties (depending upon role).
  • Transition metals form a wide range of alloys with each other.
  • Their atoms are of a similar size and behaviour and so the lattice structure of the metal won’t alter greatly as a result of substituting one atom for another.
  • Even so, alloying metals modifies the properties of the metal and usually makes it harder and less malleable.

The effect of alloying on metal properties

  • Metallic bonds are strong but directed between particular atoms.
  • When a force is applied to a metal crystal, the layers can slide past each other (slipping). After slipping has occurred, the atoms will stay in their new regular close-packed structure.
  • This is the reason why metals are malleable and ductile.
  • When an alloy is added to the metal, the orderly arrangement of the lattice is disrupted; this prevents the metal layers from sliding past each other.
  • Smaller atoms can also be added into the metal lattice (often non-metals such as carbon or nitrogen); these fit into the holes between the atoms.
  • This has the same effect of distorting the regular structure, thus making slip between the layers more difficult.

Useful books for revision

Revise A2 Chemistry for Salters (OCR A Level Chemistry B)
Salters (OCR) Revise A2 Chemistry