DLC Coatings for Knife Blades?

A. DLC coatings cover a broad spectrum of coatings with a very wide range of properties and applications. DLC coatings range from less hard to very hard. Those that are less hard have a hardness similar to titanium nitride or less. These are generally deposited by sputtering or PaCVD and are chosen for their low coefficient of friction for sliding applications.

On the very hard site we find CVD diamond coatings and non-hydrogenated cathodic arc deposited DLC (TETRABOND®). PaCVD deposited DLC coatings are deposited at under 200 °C and have a rather low oxidation temperature (300 °C or less). Sputtered DLC coatings have the broadest range of hardness and are generally deposited at 200-400 °C. Oxidation temperature is 300-600 °C. CVD diamond coatings are very hard, but are deposited at temperatures over 900 °C. TETRABOND is deposited at under 150 °C and has an oxidation temperature of 500-800 °C. Deposition times vary with door to door times ranging from around 3 hours for PaCVD and TETRABOND to 4-6 hours for sputtering to over 8 hours for CVD.

In terms of your application, TETRABOND is likely an ideal choice. It is currently used in numerous blade and cutting tool applications, from razors to drills and end mills.