Properties of Deposited Materials

Vacuum arc deposited coatings tend to have compressive stress that is due to the impact energy of ions on the part being coated. Titanium nitride can be deposited on cutting tools at relatively low temperatures and still maintain excellent adhesion and cutting characteristics.

The deposition of carbon films by the cathode arc presents a particularly interesting example. The carbon films produced by the deposition of ions of roughly 20 eV energy have a hardness of 40 to 100 GPa (6 to 15 x 106 psi), a modulus of 300 to 500 GPa (45 to 75 x 106 psi), and an optical transmission of 0.5 to 50 pm. The coating is amorphous, with primarily sp3 bonding characteristic of crystalline diamond. It has a low coefficient of friction, 0.02 to 0.1, and a hydrogen content of less than 0.1%. This is an example of a material that can only be produced by the condensation of energetic ions.

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