Reactive evaporation :

Metal atoms are evaporated from an evaporant source with a partial pressure of a reactive gas present in the chamber.

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Reactive evaporation is preferred to direct evaporation

1. During the evaporation, partial dissociation of the alloys, compounds.
   For example,
   • AL2O3 coatings prepared by direct evaporation are oxygen-deficient.
   • TiC coatings are carbon-deficient
2. Reactive evaporation can form stoichiometric oxides, alloys
   • AL2O3 : evaporation in the presence of oxygen or a postdeposition anneal in oxygen
   • TiC : evaporation in the presence of a partial pressure of acetylene.

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