Alloying Metal
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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).
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Transition metals form a wide range of alloys with each other.
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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.
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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
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Metallic bonds are strong but directed between particular atoms.
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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.
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This is the reason why metals are malleable and ductile.
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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.
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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.
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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
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