Hard Coatings on Tools

Hard coatings, formed by reactive Physical Vapor Deposition ( PVD) processes, based on plasma technology,are becoming widely used in the tool industries. 

The most common vaporization sources for the ion plating of hard coatings are unbalanced-magnetron- -sputtering sources, and cathodic-arc-vaporization sources. Bombardment during deposition is commonly achieved by applying a negative bias (-200 to -300 volts ) to the substrate and accelerating positive ions to the surface from a plasma. A high ratio of bombarding ions to depositing atoms is important for densifying the depositing material. In the unbalanced-magnetron-sputtering source, few of the sputtered atoms are ionized; but in the cathodic arc sources, a high percentage of the vaporized atoms are ionized. Because these “ film ions ” have a higher mass than do the gas ions, they are better able to sputter surfaces and densify films by “ atomic peening.” 

Industrial tool coatings are typically 1.5 to 4 microns in thickness.