PVD is a process, DLC is one of the coatings applied using that process. PVD= physical vapor deposition, basically using plasma to vaporize the coating material, and electrostatic charge to plate that vapor to the material surface. edit: little mistake, it's not exactly electrostatic charge, rather the coating is vaporized via plasma and then somehow they "bombard" the part to be coated with the vapor. Titanium nitride, DLC, Boron Carbide, are all PVD coatings. DLC = diamond like carbon, which is a pretty accurate description, it's not quite diamond but is made primarily of carbon and has similar molecular structure/hardness. Most of the time I see DLC referred to as Tungsten DLC, so I assume tungsten is part of the process somewhere but haven't found out whether it's a pre-coating plating, or if it's actually part of the DLC itself. DLC and boron carbide are probably the hardest of the PVD coatings you'll see on a regular basis.