The main characteristics of DLC coating

Characteristics Description

The hardness can reach 20 - 80 GPa (close to that of natural diamonds), with extremely strong scratch resistance. Low friction coefficient,Smooth surface, with a low friction coefficient (0.1 - 0.2), suitable for moving components Chemical inertness, Resistant to corrosion by acids, alkalis and salts, suitable for harsh environments Infrared high transmittance / It still maintains a high transmittance in the 8-14 μm band (over 88%).it Can be used in medical devices such as endoscopes and surgical instruments

Why does the DLC coating still maintain a high transmittance in the 8-14μm wavelength range?

In infrared optics (such as thermal imaging, laser transmission), 8-14 μm is an important wavelength band. However, many materials have strong absorption in this wavelength range. The key to maintaining high transmittance with DLC coating lies in its low absorption rate (the carbon bond structure of DLC makes its absorption extremely low in the mid-to-long infrared wavelength range), the controllable refractive index (by adjusting the deposition process (such as PECVD), the refractive index of DLC can be matched with the substrate material, reducing reflection loss), and ultra-thin uniformity (DLC coatings are usually only a few hundred nanometers thick, which will not significantly affect the penetration of infrared light).

Typical data:

The single-layer DLC coating has a transmittance of over 88% in the 8-14 μm wavelength range.

Combining AR coating (such as one layer of AR and one layer of DLC), the transmittance can be further increased to over 90%.