It's possible to coat many materials on the surfaces with PVD. Most common hard coatings in this field are:
TiN , AlTiN , DLC , CrN , TiCN , ZrN
They are hard coatings. But it's possible for other reasons and goals to coat other materials.
For example an electrical conductive metal or semi-conductive material can be coated on a non-conductive material for electrical purpose.
Many of special coatings is used for reflex glasses, UV glasses, self cleaning materials and etc. Almost every materials can be coated in PVD, If there is a proper way to vaporize the material.
Ways to Vaporize
It's necessary to an evaporation supply to vaporize materials for PVD coatings. There are some known ways to vaporize the materials.
These ways are used in GSCo:
• Resistive Evaporation
• Arc Evaporation (Cathodic Arc)
• Magnetron Sputtering
Also complemental processes like Ion Beam, Sputtering, Bias Voltage and … are used to achieve the best result.