Technologies
Hot Air
Heating in normal atmosphere. This method is low cost, high throughput and well controlled, also larger pieces can be made.
Controlled atmosphere
Heating in controlled atmosphere, can be in inert gas including Ar, He and Xe, as well as reactive gas including Methane, Benzene and Hydrogen.

Induction
Very rapid heating by inducing electric eddy currents in the metal. Usually used in continuous production.

Vacuum
Heating in high vac or ultra high vac ensures no atmosphere interaction. This method makes sputter cleaning and deposition possible.