High efficiency surface roughness measuring system for hard thin films deposited by cathodic arc evaporation

Zirconium carbon nitride (ZrCN) hard films own lower friction coefficient, high hardness, higher wear and corrosion resistance. Investigations on the surface roughness of ZrCN hard thin films become an important issue because the surface roughness of ZrCN hard thin films is widely believed to be related to its characteristics of wear and corrosion resistances. A new optical measuring system is developed to measure surface roughness of ZrCN hard thin films deposited by cathodic arc evaporation. A fixture of photodetector is designed and implemented for reducing the modulation time during optical measurements. The incident angle of 20° is found to be a good candidate for predicting the surface roughness of ZrCN hard thin films. Surface roughness of ZrCN hard thin films can be determined rapidly from the average value of the reflected direct current voltage recorded by the optical measuring system using the trend equation. The maximum measurement error of the optical measuring system developed is less than 12.37%. The savings in measurement time of the surface roughness of ZrCN hard thin films is up to 93.33%.