Carbon-based Coatings					Nitrides
	Metal-doped DLC Me-DLC (WC-C:H)	Amorphous Hydrogenated DLC (a-C:H)	Silicon- doped DLC (a-C:H-Si)	Sputtered DLC (a-C)	Hydrogen- free DLC (ta-C)	Chrome- Nitride (CrN)
Method	PVD/PACVD	PACVD	PACVD	PVD	PVD	PVD
Hardness (HV 0.05)	800-2200	1500-3500	1500-2500	2000-4000	3000-7000	2000-2200
Coefficient of friction	0.1-0.2	0.05-0.15	0.05-0.1	0.05-0.1	0.02-0.1	0.4
Internal stress (Gpa/μm)	0.1-1.5	1-3	1-3	2-6	1-3	0.1-1
Thickness (μm)	1-10	1-3	1-3	1-3	1-3	1-40
Industrial use	+++	+++	+++	+++	++	+++
Mass production	+++	+++	+	+++	+	+++

A new tribological PVD coating is the Superhard-ULF coating. It is a nano-composite coating system designed to interact with the lubricant to form a lubricious tribological nano-layer on the contact surface. Please download the article to read more.